SAGA2 UserGuide Cimmery 20070401

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User Guide for SAGA (version 2.0)

By Vern Cimmery

March, 2007


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User Guide for SAGA (version 2.0)

Copyright 2004 Vern Cimmery

Permission is granted to copy, distribute and/or modify this document In return, licensees may not use the

work for commercial purposes unless they get the licensors permission. The license applies to the entire

text of this book, plus all the illustrations that are by Vern Cimmery.

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TABLE OF CONTENT

Chapter 1 Introduction to SAGA Version 2.0 1

Organization of this User Guide 3

About the Examples 4

Chapter 2 The Graphic User Interface (GUI) and More 6

Overview 6Menu Bar 7

Menu Bar: File 8

Introduction to the SAGA project and spatial environment 8

File: Project 12File: Project: Load Project 14

File: Project: Save Project 16

File: Project: Save Project As 17File: Project: recent loads 18

File: Table - Overview 18File: Table: Load Table 19File: Shapes - Overview 20

File: Shapes: Load Shapes 20

File: Shapes: recent loads 21File: T.I.N. 22

File: Grid 22

File: Grid: Load Grid 22

File: Grid: recent loads 24File: Exit 24

Menu Bar: Modules 26

Modules: Load Module Library 26Menu Bar: Window 28

Window: Show Workspace 29

Window: Show Object Properties 39Window: Show Message Window 43

Window: Cascade 44

Window: Tile 45

Window: Arrange Icons 46Window: Next; Window: Previous 46

Window: Close; Window: Close All 46

Chapter 3 The Workspace Modules Tab Environment 48Load Module Library 49

Close 50The Menu Bar Modules Title 50

The Workspace Modules Tab 51The Module Function Parameter Settings Page 53

Module Libraries 59

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Chapter 4 The Workspace Data and Layers Tabs Environment 67

The Workspace Data Tab Area 67Object Properties Parameter Settings for a Grid Data Layer 72

General: Name 75

General: Show Legend 75

General: Unit 76General: Z-Factor 77

No Data 78

Display: Transparency [%] 79Display: Interpolation 83

Display: Visibility: Always Show 83

Display: Visibility: Scale Dependent 83Display: Color Classification: Type 83

Display: Color Classification: Value Range 93

Display: Color Classification: Mode and Logarithmic Stretch Factor 94

Memory 95

Memory: Buffer Size [MB] 97Display: Cell Values 99

Display: Cell Values: Show 99Display: Cell Values: Font 99

Display: Cell Values: Relative Font Size 99

Display: Cell Values: Decimals 99The Description Tab Area of the Object Properties Window 101

The Legend Tab Area of the Object Properties Window 104

The Attributes Tab Area of the Object Properties Window 106Object Properties Parameter Settings for Shapes Data Layers 106

General: Name 109General: Show Legend 109

Display: Chart 111

Display: Fill Style 114

Display: Outline 118Display: Outline Color 118

Display: Outline Size 119

Display: Symbol Type 120Display: Symbol Image 121

Display: Show Points 121

Display: Visibility: Always Show 122Display: Visibility: Scale Dependent 122

Display: Color Classification 123

Display: Color Classification for Point and Polygon Shapes Data Layers 126Graduated Color: Value Range 131

Display: Label 132

Display: Label: Attribute 132

Display: Label: Size relates to 135Display: Size for Point and Line Shapes Data Layers 140

The Object Properties Tabs: Description, Attributes, Legend and Info. 143

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The Description Tab Area of the Object Properties Window 144

The Attributes Tab Area of the Object Properties Window 147The Legend Tab Area of the Object Properties Window 149

Additional Tools Available in the Data and Layers Tab Areas of the Workspace

Window 152

Close 153Save Grid (or Save Shapes) 155

Save Grid As (or Save Shapes As) 155

Save Grid As Image 156Show Grid (and Show Shapes) 160

The Shapes Data Layer Create Lookup Table Command 160

Show Histogram 163Show Scatterplot 172

Create Normalised Classification 178

Edit Tools Available for Shapes Data Layers 180

Edit: Add Shape 181

Edit: Edit Selected Shape 185Edit: Delete Selected Shape(s) 188

Chapter 5 The Workspace Maps Tab 191

The Workspace Maps Tab Area 191

Menu Bar: Map 201Map: Save As Image 203

Map: Save As PDF 206

Map: Save as Interactive SVG 211Map: Zoom To Previous Extent ( ) 211

Map: Zoom To Full Extent ( )211Map: Zoom To Active Layer ( ) 212

Map: Zoom To Selection ( ) 213

Map: Zoom To Extent 214

Map: Synchronise Map Extents ( ) 215Map: Action ( ) 216

Map: Zoom ( ) 219

Map: Pan ( ) 219Map: Measure Distance ( ) 220

Map: Show 3D-View 220

3D-View: Properties [ ] 2263D-View: Rotation 227

3D-View: Rotation: Up [ ], 3D-View: Rotation: Down [ ] 228

3D-View: Rotation: Left [ ], 3D-View: Rotation: Right [ ] 229Rotation: Y 230

3D-View: Shift 231

3D-View: Shift: Left [ ], 3D-View: Shift: Right [ ] 231

3D-View: Shift: Down [ ], 3D-View: Shift: Up [ ] 2323D-View: Shift: Forward [ ], 3D-View: Shift: Backward [ ] 233

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3D-View: Decrease Exaggeration [F1] [ ], 3D-View: Increase Exaggeration [F2] [ ]

2343D-View: Central Projection 235

Projection: Projection 235

Projection: Perspectivic Distance 235

3D-View: Decrease Perspectivic Distance [ ], 3D-View: Increase Perspectivic Distance [] 235

Figure 236

Weight 2373D-View: Interpolated Colors [ ] 238

3D-View: Anaglyph [S] [ ] 239

3D-View: Decrease Eye Distance [F5], 3D-View: Increase Eye Distance [F6] 240Eye Distance [Degree] 240

3D-View: Interpolated 240

Background Color 240

Resolution 240

3D-View: Save As Image 2413D-View: Sequencer 243

Map: Show Print Layout 245Map-Layout: Fit Scale 247

Map-Layout: Page Setup ( ) 250

Map-Layout: Print Preview ( ) 251Map-Layout: Print ( ) 251

Chapter 6 Working with Tables in SAGA 252

Introduction To Tables 252

The Menu Bar File Table Option 252The Table Options on the Menu Bar and Toolbar 255

Add Field 257

Delete Fields 258

Add Record 259Insert Record 259

Delete Record 259

Delete All Records 259Fit Column Sizes 259

Sort Fields 260

Fit Row Sizes 261The Histogram Convert To Table Option 261

The Grid Data Layer Color Lookup Table 265

The Shapes Data Layer Color Lookup Table 270Using the Shapes Create Lookup Table Command 270

The Player Sequence Table 274

The Shapes Data Layer Attribute Table 275

Using the Table Calculator for Shapes Module 281

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Chapter 7 Some SAGA How tos 287

Introduction 287List of Data Layers, Tables and Maps In Work Session 287

Rename a Grid or Shapes Data Layer 291

The SAGA Grid Calculator 294

Using the Grid Calculator Module to Create a New Grid Data Layer from a DataCategory 299

Creating Slope and Aspect Maps From a DEM 302

Developing Terrain Form Data Layers 308Creating Shape Contour Data Layers 314

Preparing a DEM Data Layer for Hydrology Analysis 319

Calculating Catchment Area 324Defining Channel Networks 332

Defining Watershed Basins 338

Creating a Vector Layer of a Grid Data Layer 340

RECODE or Re-Classifying Grid Data Values 346

Using the Change Grid Values Module 346Using the Reclassify Grid Values Module 351

The Buffer Function in Action 361VIEW SHED Analysis 366

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LIST OF FIGURES

Figure 1 1 Location of Washington State, USA. 4Figure 1 2 Mason County, Washington State. 4

Figure 2-1. The SAGA display window. 6

Figure 2-2. The major parts of the SAGA GUI. 7

Figure 2-3. The File drop-down menu of options. 8Figure 2-4. The project object properties. 13

Figure 2-5. The Load Project dialog window. 15

Figure 2-6. The Close data sets message. 16Figure 2-7. The Save Project dialog window. 18

Figure 2-8. The Load Table dialog window. 19

Figure 2-9. A portion of the MCroadsAll.dbf attribute table file. 20Figure 2-10. The Load Shapes dialog window. 21

Figure 2-11. The Load Grid dialog window. 23

Figure 2-12. The Save Modified Data Objects dialog window. 24

Figure 2-13. Using the Save parameter in the Save Modified Data Objects dialog

window. 25Figure 2-14. Accessing File options from the Data and Grids sections in the Data

tab area of the Workspace window. 26Figure 2-15. The Load Module Library dialog window. 27

Figure 2-16. The Menu Bar Window drop-down menu of options. 28

Figure 2-17. The SAGA display with no windows showing. 29Figure 2-18. The SAGA Workspace window. 30

Figure 2-19. Options available in the Data tab area of the Workspace. 31

Figure 2-20. The Menu Bar with the Histogram title added. 32Figure 2-21. The parameter settings page for creating a scatter plot. 32

Figure 2-22. The menu bar with the Scatterplot title added. 32Figure 2-23. Pop-up menus available for vector data layers in the Data and Layers tab

areas of the Workspace. 33

Figure 2-24. The map view window for the MCdem30 DEM grid data layer. 34

Figure 2-25. The Map tab area of the Workspace window. 34Figure 2-26. The Add layer to selected dialog window. 35

Figure 2-27. The definition for map 1 with two data layers. 35

Figure 2-28. The definition for map 2 with one data layer. 36Figure 2-29. The map view windows for maps 1 and 2. 36

Figure 2-30. The list of options available from the Maps tab area of the Workspace.

37Figure 2-31. The list of options available from a map layer of a map. 37

Figure 2-32. The Map title on the Menu Bar. 38

Figure 2-33. The Menu Bar Map drop-down list of options. 38Figure 2-34. Additional options generated by Show 3D-View and Show Print

Layout. 39

Figure 2-35. The Object Properties window of the SAGA display. 40

Figure 2-36. The Settings tab area of the Object Properties window. 41Figure 2-37. The Description tab area of the Object Properties window. 42

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Figure 2-38. The Legend tab display in the Object Properties Window for a DEM grid

data layer and a railroad line vector data layer. 42Figure 2-39. A typical Show Message Window display. 43

Figure 2-40. Execution tab information in the Message window for the Calculator

module. 44

Figure 2-41. Using the Cascade command to organize map view windows. 45Figure 2-42. Using the Tile command to organize map view windows. 46

Figure 3-1. The Menu Bar Modules title drop-down menu of options. 48

Figure 3-2. The Load Module Library dialog window. 49Figure 3-3. The Delete dialog window. 50

Figure 3-4. Selecting the Grid Buffer function for execution. 51

Figure 3-5. The Workspace Modules tab list of options. 52Figure 3-6. Expanding the option list for Grid - Gridding. 52

Figure 3-7. An example parameter settings page. 53

Figure 3-8. The module function Grid Normalisation selected. 55

Figure 3-9. TheSettings tab area of the Object Properties window for the Grid

Normalisation module. 56Figure 3-10. The documentation for the Grid Normalisation module. 57

Figure 3-11. The Module Libraries text selected. 58Figure 3-12. The property for the Beep function. 59

Figure 4-1. Empty Data and Layers tab areas in the Workspace. 67

Figure 4-2. Menu Bar File options. 68Figure 4-3. The Data tab area of the Workspace with several data layers and tables

loaded. 69

Figure 4-4. The Layers tab area of the Workspace with several data layers loaded. 70

Figure 4-5. The Data tab area of the Workspace after loading the Mason project. 72

Figure 4-6. The properties for the MCschoolDist grid data layer in the Settings tab

area of the Object Properties window. 73

Figure 4-7. Two map layout windows one with a legend and one without. 75Figure 4-8. The Unit parameter and the Z display field. 76

Figure 4-9. Using the Unit parameter with the data layer legend display. 77

Figure 4-10. Using a Z-Factor to convert elevation feet to meters. 78Figure 4-11. Maps with the Transparency parameter set to 0%. 80

Figure 4-12. The effect of changing the transparency to 50% for the roads data layer.

81Figure 4-13. Combining a thematic grid data layer with a shaded-relief data layer. 82

Figure 4-14. The default Table for a grid data layer. 85

Figure 4-15. The color swatch table for assigning data class colors for grid data values. 86

Figure 4-16. The Table and legend for the census tract grid data layer. 86

Figure 4-17. A Lookup Table for displaying cell values in four data display classes.

87Figure 4-18. How the Lookup Table affects the appearance of a grid data layer. 88

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Figure 4-19. Comparing a grid data layer using two different color ramps for display.

88Figure 4-20. The Colors window used with color ramps. 89

Figure 4-21. The Input dialog window for changing the number of color ramp classes

using the Count button. 90

Figure 4-22. The Colors window using a value of 16 for the Count variable. 91Figure 4-23. List of pre-defined color ramps. 92

Figure 4-24. The Save Colors dialog window. 93

Figure 4-25. An example of using the Logarithmic (up) mode with a catchment areagrid data layer. 95

Figure 4-26. The Memory parameters. 96

Figure 4-27. The difference in the Description tab area of the Observation Propertieswindow between the Normal setting on the left and the RTL Compression setting on

the right. 96

Figure 4-28. The Description tab area of the Object Properties window for the

Memory Handling parameter set to File Cache. 97

Figure 4-29. Global parameters related to memory handling. 98Figure 4-30. Zoomed in to view grid cell data values. 100

Figure 4-31. Viewing different text parameter settings. 100Figure 4-32. The Description tab area for the MCaspect-deg grid data layer. 101

Figure 4-33. The Description tab area for the MCaspectClasses2 grid data layer.

103Figure 4-34. Display of the McaspectClasses2.hgrd file using Word. 104

Figure 4-35. The Object Properties window Legend tab area for the

MCslopeDegrees grid data layer. 105Figure 4-36. The Legend tab area for a discrete data set. 106

Figure 4-37. The properties page for a polygon shapes data layer. 108Figure 4-38. Viewing a grid data layer legend in a map layout view window. 109

Figure 4-39. Displaying the legend with the Legend tab at the bottom of the Object

Properties window. 110

Figure 4-40. The Mason County school district shapes data layer. 111Figure 4-41. The Chart Properties dialog window. 112

Figure 4-42. The attribute table for the Mason County school district data layer. 113

Figure 4-43. Using the Charts parameter with the MCwaters-Poly shapes data layer. 114

Figure 4-44. The Fill Style pop-up list of options. 114

Figure 4-45. The map view window for map 3 that includes two data layers. 115Figure 4-46. The grid data layer for Mason County census tracts. 116

Figure 4-47. Using the Transparent fill style for the waters polygon shapes data layer.

117Figure 4-48. Using the Backward diagonal fill style for the waters polygon shapes data

layer. 117

Figure 4-49. List of color options for polygon and symbol boundaries. 118

Figure 4-50. Defining a Custom color for polygon and symbol boundaries. 119Figure 4-51. Comparing two different Outline Size parameter settings for shapes data

layers. 119

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Figure 4-52. List of symbols for displaying point data. 120

Figure 4-53. Map 5 illustrating symbol options. 121Figure 4-54. Viewing line features on a shapes data layer with Show Points turned on.

122

Figure 4-55. The Description tab for the waters polygon shapes data layer. 124

Figure 4-56. The empty Attributes tab area for the waters polygon shapes data layer. 125

Figure 4-57. The red-outlined water polygon is selected and highlighted. 125

Figure 4-58. The attributes for the selected water polygon. 126Figure 4-59. The waters polygon shapes data layer with the Unique Symbol option

selected. 127

Figure 4-60. A DEM grid data layer and water polygons shapes data layer combined for amap. 127

Figure 4-61. An example of the school district shapes data layer with the Graduated

Color option selected. 128

Figure 4-62. The Table used with the Lookup Table option. 129

Figure 4-63. The color table for assigning data class colors for a map display. 130Figure 4-64. A color table modified for the LANDPOLY attribute for water features

shapes data layer. 131Figure 4-65. The Mason County school district shapes data layer. 132

Figure 4-66. The pop-up list for the Attribute value field. 133

Figure 4-67. The ID labels displayed using the defaults. 133Figure 4-68. The Font dialog window. 134

Figure 4-69. Using the Lucida Sans font, bold font style, and size 18. 135

Figure 4-70. Using Map Units option for Size relates to and a Default Size of100. 136

Figure 4-71. Using Map Units for Size relates to and a Default Size of 1500. 137

Figure 4-72. The Edit parameters for a shapes data layer. 137

Figure 4-73. Map 1 displaying the ObservLoc and MCroadsAll shapes data layers.

138Figure 4-74. The Snap to dialog window. 139

Figure 4-75. The updated ObservLoc point shapes data layer. 140

Figure 4-76. The Display: Size parameter section for a transportation shapes data layer. 141

Figure 4-77. A zoomed in portion of the Mason County drainage map. 141

Figure 4-78. Changing the Default Size parameter for Display Size to 4. 142Figure 4-79. Setting the Minimum and Maximum parameter values to 1 and 10.

143

Figure 4-80. The legend for drainage features based on the Minimum and Maximumparameter values to 1 and 10. 143

Figure 4-81. The Description tab area of a shapes data layer in the Object Properties

window. 144

Figure 4-82. A sample attribute table in the Description tab area of the ObjectProperties. 145

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Figure 4-83. The Description tab area for the MCaspectClasses2 grid data layer.

146Figure 4-84. Display of the McaspectClasses2.hgrd file using Word. 147

Figure 4-85. The empty Attributes section for a waters polygon shapes data layer.

148

Figure 4-86. The red-outlined water polygon is selected and highlighted. 148Figure 4-87. The attributes for the selected water polygon. 149

Figure 4-88. Comparing legends for the ID and LANDPOLY attributes for the

polygon shapes data layer. 149Figure 4-89. A shapes data layer legend with Type set to Unique Symbol. 150

Figure 4-90. A Lookup Table for use with the ID attribute for water polygons.

151Figure 4-91. A legend with Type set to Lookup Table using the table in Figure 4-90.

151

Figure 4-92. A legend with Type set to Graduated Color and a Count variable of

15. 152

Figure 4-93. Options available from the Data and Layer tab areas of the Workspacewindow for grid and shapes data layers. 152

Figure 4-94. The Delete dialog window. 153Figure 4-95. The Save Modified Data Objects dialog window. 153

Figure 4-96. The Save dialog window for identifying a storage path and file name.

154Figure 4-97. The Save Grid dialog window used with the Save Grid As command.

156

Figure 4-98. The dialog window for the Save As Image tool. 157Figure 4-99. The Save Grid as Image dialog window. 158

Figure 4-100. An image saved with the Save Grid As Image tool. 159Figure 4-101. The georeference file content. 159

Figure 4-102. The Add layer to selected map dialog window. 160

Figure 4-103. The Choose Attribute dialog window. 161

Figure 4-104. Pop-up list of attributes. 161Figure 4-105. The CensusPolygons legend displayed in the Legend tab area of the

Object Properties window. 162

Figure 4-106. A Lookup Table created from executing the Create Lookup Tablecommand. 163

Figure 4-107. A histogram for a DEM grid data layer. 164

Figure 4-108. The legend for a DEM grid data layer. 164Figure 4-109. Using the histogram to adjust a grid data layer color display. 165

Figure 4-110. The Histogram title on the Menu Bar. 165

Figure 4-111. Comparing the standard and cumulative histogram versions. 166Figure 4-112. The Tables area of the Data tab area of the Workspace. 167

Figure 4-113. The Table title in the Menu Bar. 168

Figure 4-115. The Menu Bar Table options. 169

Figure 4-116. Commands to use with tables. 169Figure 4-117. The diagram properties setting window. 170

Figure 4-118. A Diagram view window using the Show Diagram command. 171

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Figure 4-119. A Diagram view window for Mason County census tracts. 172

Figure 4-120. The Scatterplot: MCdem30.dgm parameter settings window. 173Figure 4-121. The Scatterplot: MCdem30.dgm parameter settings window using the

MCroadsAll2 grid data layer. 174

Figure 4-122. The MCdem30 versus MCroadsAll2 scatter plot. 174

Figure 4-123. The Properties window for the MCdem30 versus MCroadsAll2 scatterplot. 175

Figure 4-124. The Regression Details window display. 175

Figure 4-125. Font choices available for the scatter plot. 176Figure 4-126. The Colors dialog window used for selecting the scatter plot colors.

177

Figure 4-127. A scatter plot comparing a grid data layer (WSslope) and theWSwetnessIndex grid data layer. 178

Figure 4-128. DEM grid data layer histogram. 179

Figure 4-129. A normalized classification applied to a DEM with 100 classes set. 179

Figure 4-130. A normalized classification applied to a DEM with 255 classes set. 180

Figure 4-131. Edit tools available from a shapes data layer map view window. 181Figure 4-132. An enlarged portion of the Mason County road shapes line data layer.

181Figure 4-133. The shape feature Edit tool options. 182

Figure 4-134. The Edit options list after selecting the Add Shape tool. 182

Figure 4-135. A portion of the Settings tab area for the Mason County transportationshapes data layer. 183

Figure 4-136. A new road in the road shapes data layer. 184

Figure 4-137. The Edit Selected Shape command option. 184Figure 4-138. The Edit Shapes dialog window. 185

Figure 4-139. The Select icon on the Tool Bar is selected. 185Figure 4-140. A road segment selected (in red). 186

Figure 4-141. Edit tools available for use with a selected feature. 186

Figure 4-142. Using the Edit Selected Shape tool. 187

Figure 4-143. Edit tools for use with a selected feature point. 188Figure 4-144. The Delete Selected Part tool dialog. 188

Figure 4-145. Roads selected for deletion. 189

Figure 4-146. The Edit Shapes dialog window for the Delete Selected Shape(s) tool. 189

Figure 4-147. The roads are deleted. 190

Figure 5-1. List of grid data layers in the Data area of the Workspace. 192Figure 5-2. The map view window for displaying the MCcensustracts grid data layer.

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Figure 5-3. The Maps area of the workspace. 194Figure 5-4. Two map view windows displayed in the work area. 196

Figure 5-5. The Add layer to selected dialog window. 197

Figure 5-6. 01. Map with two data layers displayed. 198

Figure 5-7. Displaying channel network on a DEM. 199Figure 5-8. Map area pop-up menu of options. 200

Figure 5-9. Example of using Fit Grid Colors to Map Extent. 201

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Figure 5-10. The Map title on the Menu Bar. 201

Figure 5-11. The Map drop-down list of options. 202Figure 5-12. Map options added to the toolbar. 202

Figure 5-13. The Save As Image dialog window. 204

Figure 5-14. The Save Map as Image ... parameters page. 205

Figure 5-15. A JPEG file of the MCcensusPolys grid data layer created in SAGA. 206

Figure 5-16. The Save to PDF properties page. 207

Figure 5-17. A Save dialog window. 208Figure 5-18. The Save to PDF properties page for the sample PDF document. 209

Figure 5-19. Viewing the PDF file for the MCcensustracts map layout. 210

Figure 5-20. The Grapeview school district used to select a portion of the census tractgrid data layer. 211

Figure 5-21. Comparing Full Extent map view windows. 212

Figure 5-22. Using the Zoom To Selection tool. 213

Figure 5-23. A Map Extent properties window. 214

Figure 5-24. The Save Parameters dialog window. 215Figure 5-25. Using the Action tool with a grid data layer. 217

Figure 5-26. Using the Action tool with a shapes data layer. 218Figure 5-27. A three-dimensional or perspective view of a digital elevation grid data

layer. 221

Figure 5-28. Checking for data errors. 221Figure 5-29. Draping a data layer over a three dimensional display of elevation. 222

Figure 5-30. The 3D-View properties window. 223

Figure 5-31. The 3D-View view window. 224Figure 5-32. The 3D-View title on the Menu Bar. 224

Figure 5-33. 3D-View title drop-down menu of options. 225Figure 5-34. Adding 3D-View options to the toolbar. 225

Figure 5-35. The 3D-View properties window. 227

Figure 5-36. The rotation axes. 228

Figure 5-37. Using the Up rotation command. 229Figure 5-38. Using the Right rotation command. 230

Figure 5-39. Using the Y parameter on the 3D-View properties page. 231

Figure 5-40. Using the Shift Left tool. 232Figure 5-41. Using the Shift Up tool. 232

Figure 5-42. Using the Shift Backward tool. 233

Figure 5-43. The effect of the exaggeration factor. 234Figure 5-44. The effect of perspectivic distance. 236

Figure 5-45. The effects of the Figure parameter. 237

Figure 5-46. The effects of the Figure parameter using a Weight of .35. 238Figure 5-47. Comparing perspectives with and without interpolation operating. 239

Figure 5-48. Comparing Resolution values of 50 and 200. 241

Figure 5-49. The Save As Image dialog window. 242

Figure 5-50. A JPEG file of a perspective image created in SAGA. 243Figure 5-51. The Sequencer table of frames. 244

Figure 5-52. The Map Layout title on the Menu Bar. 245

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Figure 5-53. The Map Layout drop-down list of options. 245

Figure 5-54. Additional Map Layout commands added to the toolbar. 246Figure 5-55. The Map Layout view window for the Mason County DEM data layer.

247

Figure 5-56. The pop-up menu produced by right-clicking on the 01. Map name in the

Maps tab area of the Workspace. 247Figure 5-57. The Map Layout view window for the MCcensusPolys grid data layer.

248

Figure 5-58. The Fit Map Scale dialog window. 248Figure 5-59. The MCcensusPolys grid data layer using a scale of 1:35000. 249

Figure 5-60. The Page Setup dialog window. 250

Figure 6 1 The Load Table command in the Menu Bar File drop-down menu. 252Figure 6-2. The Load Table dialog window. 253

Figure 6-3. The Tables section of the Data tab area of the Workspace window. 254

Figure 6-4. The Tables pop-up list of options. 255

Figure 6-5. The Menu Bar and toolbar modifications. 255

Figure 6-6. The PrecipReclass table. 256Figure 6-7. The Add Field edit tool dialog window. 257

Figure 6-8. The options for Field Type. 258Figure 6-9. The Delete Fields dialog window. 258

Figure 6-10. A pop-up list of options for editing fields. 259

Figure 6-11. The Sort Table dialog window. 260Figure 6-12. A pop-up list of options for editing rows. 261

Figure 6-13. The SAGA histogram for a slope aspect grid data layer. 262

Figure 6-14. The Histogram title on the Menu Bar. 262Figure 6-15. The Tables section of the Data tab area. 263

Figure 6-16. The Table title on the Menu Bar. 263Figure 6-17. The DEM grid data layer histogram in its table form. 264

Figure 6-18. The default lookup table for a grid data layer. 265

Figure 6-19. The lookup table for census tracts. 267

Figure 6-20. The Save Table dialog window. 268Figure 6-21. Using a lookup table in the Table mode. 269

Figure 6-22. Accessing the Create Lookup Table command. 271

Figure 6-23. The Choose Attribute dialog window used with the Create Lookup Tablecommand. 271

Figure 6-24. The color lookup table created by the Create Lookup Table command

using the NAME attribute. 273Figure 6-25. The updated shapes data layer legend. 274

Figure 6-26. The 3D View: Player Sequence table. 275

Figure 6-27. The Load Table dialog window. 277Figure 6-28. The Load Table dialog window using the All Files choice. 278

Figure 6-29. The MCwaters-Poly shapes data layer attribute file. 279

Figure 6-30. The Table calculator for shapes parameter page. 281

Figure 6-31. The data entries for creating the new Pop/HU attribute. 283Figure 6-32. The Description tab area for the MCcensus-poly shapes data layer.

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Figure 6-33. The Shapes to Grid parameter page. 285

Figure 6-34. The Choose Project parameter settings. 286Figure 6-35. The population per housing unit grid data layer and legend. 286

Figure 7-1. An example of the Data tab area list in the workspace. 288

Figure 7-2. The Maps tab area list in the Workspace window. 290

Figure 7-3. The parameters page for a DEM data layer. 292Figure 7-4. The Grid Calculator parameter settings page. 294

Figure 7-5. The Grids input window for the Grid Calculator module. 295

Figure 7-6. The two population grid data layers in Map Layout view windows. 296Figure 7-7. The Grid Calculator settings page used for the ADD example. 297

Figure 7-8. The composite grid data layer for total population. 297

Figure 7-9. The initial Grid Calculator parameter settings page. 300Figure 7-10. The Grids input window. 300

Figure 7-11. The Grid Calculator parameter settings window used with a Boolean

formula. 301

Figure 7-12. The Local Morphometry module parameters page. 302

Figure 7-13. The parameter settings page for creating Slope and Aspect grid data layerswith the Local Morphometry module. 303

Figure 7-14. Slope and Aspect grid data layers created with the Local Morphometrymodule. 304

Figure 7-15. The Z-Factor parameters for the new Slope and Aspect grid data layers.

305Figure 7-16. The initial Grid Calculator settings page. 306

Figure 7-17. The Grid Calculator settings page with a formula for converting Radians to

Degrees. 306Figure 7-18. The parameter settings page for the Surface Specific Points module. 308

Figure 7-19. The terrain form grid data layer. 310Figure 7-20. The Grid Calculator module parameter settings page. 311

Figure 7-21. The Grid Calculator module parameter settings page using a Boolean

formula to create a ridge landform grid data layer. 312

Figure 7-22. A new grid data for the ridges landform. 312Figure 7-23. The Contour Lines from Grid module parameter settings page. 314

Figure 7-24. Final settings for execution of the Contour Lines from Grid module. 315

Figure 7-25. The Object Properties parameter settings for the new contour shapes datalayer. 317

Figure 7-26. The DEM grid data layer with a contour overlay. 318

Figure 7-27. The Sink Removal parameter settings page. 319Figure 7-28. Final settings for the execution of the Sink Removal module. 320

Figure 7-29. A new DEM grid data layer with sinks removed. 320

Figure 7-30. The Grid Calculator parameter settings page. 321Figure 7-31. The Grid Calculator parameter settings page for creating a grid data layer

showing sinks. 322

Figure 7-32. The sinks grid data layer showing the elevation differences between two

DEMs. 322Figure 7-33. Checking grid cell data values. 323

Figure 7-34. The Parallel Processing parameter settings page. 326

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Figure 7-35. The parameter settings used to generate the Catchment Area grid data

layer. 327Figure 7-36. The Catchment Area grid data layer. 328

Figure 7-37. The catchment area grid data description window. 329

Figure 7-38. The catchment area grid data description window. 330

Figure 7-39. The Catchment Area grid data layer using the Logarithmic option. 331Figure 7-40. The Channel Network parameter settings page. 332

Figure 7-41. The parameter settings used for the Channel Network module. 333

Figure 7-42. The Channel network and Channel Direction grid data layers. 334Figure 7-43. A zoomed in portion of the Channel Network grid data layer. 334

Figure 7-44. A zoomed in portion of the Channel Direction grid data layer. 335

Figure 7-45. The parameter settings page for the Channel Network shapes data layer. 336

Figure 7-46. A color table used with shapes data layers. 337

Figure 7-47. The DEM grid data layer with a vector channel network overlay. 337

Figure 7-48. The Watershed Basins module parameter settings page. 338

Figure 7-49. Watershed Basins module settings for creating a watershed basins grid datalayer. 339

Figure 7-50. A watershed basin grid data layer. 339Figure 7-51. The Vectorising Grid Classes parameter settings page. 340

Figure 7-52. The parameter settings page for the Watershed Basins shapes data layer.

342Figure 7-53. The Watershed Basins shapes data layer default display. 343

Figure 7-54. Choosing a shapes data layer polygon boundary color. 344

Figure 7-55. The watershed basin shapes data layer as an overlay on the DEM grid datalayer. 345

Figure 7-56. The slope and aspect grid data layers prior to recoding. 346Figure 7-57. The Change Grid Values module parameter settings page. 348

Figure 7-58. The Lookup Table for the slope recode. 349

Figure 7-59. Comparing the original slope data layer with the recoded data layer. 350

Figure 7-60. The Lookup Table for the aspect recoding. 351Figure 7-61. Comparing the original aspect data layer with the recoded data layer. 351

Figure 7-62. The parameter settings page for the Reclassify Grid Values module. 352

Figure 7-63. Comparing the original MCschoolDist data values to the ReclassifiedGrid values. 354

Figure 7-64. The Mason County census tract grid data layer. 354

Figure 7-65. Using the range method to combine several data values. 356Figure 7-66. A blank Lookup Table for entering data class values. 357

Figure 7-67. The Lookup Table with new data classes defined based on elevation

criteria. 358Figure 7-68. Using the table method to create input to a wildlife habitat model. 359

Figure 7-69. The color lookup table for the elevation input to a wildlife habitat model.

359

Figure 7-70. The Grid - Tools/Grid Buffer parameter settings page. 361Figure 7-71. The Grid Buffer parameter settings used to create the buffer grid data

layer. 363

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Figure 7-72. The buffer grid layer for lakes. 363

Figure 7-73. The Grid Calculator parameter settings page. 364Figure 7-74. The Grid Calculator parameter settings page for creating a new grid data

layer. 365

Figure 7-75. The grid layer identifying road areas requiring special consideration. 365

Figure 7-76. The Mason County DEM and watershed basins. 368Figure 7-77. The selected watershed basins. 369

Figure 7-78. The New layer from selected shapes parameter window. 369

Figure 7-79. A new shapes data layer based on selected watershed basins. 370Figure 7-80. The Clip Grid with Polygon parameters window. 370

Figure 7-81. The DEM grid data layer for the four watershed basins. 371

Figure 7-82. The observer location (the black plus symbol). 371Figure 7-83. The Visibility (single point) module parameters window. 372

Figure 7-84. The entries for the Visibility (single point) module parameter settings page.

373

Figure 7-85. The enlarged DEM displaying the observer location and the Visibility grid

data layers. 374Figure 7-86. The Visibility grid data layer updated. 374

Figure 7-87. Two perspectives for the Bear Gulch Camp flagpole seen area. 375Figure 7-88. The 3D-View properties page. 376

Figure 7-89. The Grid Proximity Buffer parameters window. 377

Figure 7-90. The distance buffers for the Bear Gulch Campground. 378Figure 7-91. The Reclassify Grid Values parameters page. 379

Figure 7-92. The lookup table for reclassifying the buffer zones into foreground, mid-

ground and background. 380Figure 7-93. The visual zone grid data layer. 380

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AcknowledgmentMost of the System for Automated Geo-Scientific Analysis or SAGA was created anddeveloped by the working-group Geosystem Analysis (formerly associated with

Gttingen University and currently with Hamburg University), headed by Prof. Dr.

Jrgen Bhner. The current versions of SAGA are mainly due to the creativeness and

participation of the core set of developers; namely Rdiger Kthe, Andre Ringeler, VictorOlaya, Dr. Christian Caro, Dr. Volker Wichmann, Prof. Dr. Jrgen Bhner and, in

particular Dr. Olaf Conrad, who shouldered the main programming work. However,SAGA would not have reached this level of sophistication without that multitude of

methodical innovations cooperatively worked out by the working-group Geosystem

Analysis as a whole in context with national and international environment related

research projects.

Dr. Volker Wichmann volunteered to edit the several drafts of this guide. Little did he

know that his contribution would entail a little more than edits. His edits and suggestionshave been invaluable in finalizing the effort. Equally important, however, were his

technical comments related to several of my explanations that were not quite technicallyaccurate (my quotes) for how a particular SAGA procedure operated. Volkers inputmaintained the technical accuracy required for users to have a high comfort level with the

content. I appreciate very much the time and effort Volker has contributed. This is a

better manual because of the time and effort he volunteered for his edits and reviews.

I hope you will enjoy using this User Guide as much as I have enjoyed producing it. I

continually am encountering subtle and powerful features in SAGA. Please feel free to e-

mail me if you have any questions or suggestions for improvement. My e-mail address is:

[email protected]

SAGA is what I would characterize as very forgiving software. You will find it very easy

to experiment with its functions, commands, and modules. Explore, enjoy, and learn.

This User Guide for SAGA is contributed to the SAGA user community to, hopefully,

assist the user in successfully applying the SAGA functions, tools, commands, and

procedures in addressing applications specific to spatial analysis.

Please feel free to make a copy, reference the document, etc., as you desire. I would

appreciate if you gave me credit for the effort I have invested.

There is no intention to violate any software copyrights indirectly related to SAGA.

You are free:

To copy, distribute, display, and use this manual.

To make derivative works.

Under the following conditions:

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Attribution. You must give the original author credit.

Share alike. If you alter, transform, or build upon this work, you may distributethe result.

Work only under a license identical to this one.

For any reuse or distribution, you must make clear to others the license terms of

this work. Any of these conditions can be waived if you get permission from the copyright

holder.

Your fair use and other rights are in no way affected by the above. For any further

information, please contact the author at the following email address

[email protected].

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SAGA Guide Chapter 1

Chapter 1 Introduction to SAGA Version 2.0

This guide is for version 2.0 of the System for Automated Geoscientific Analyses or

SAGA as it is most often referred. SAGA is a Geographic Information System (GIS). It

has been developed at Goettingen University in Germany. Version 2.0 is the second

major release of the SAGA program; version 1.2 being the first. I have used SAGA 2.0RC3 for the development of this manual.

The development objectives for the SAGA program are:

- To give geo-scientists an effective but easy to learn tool for the implementation of

geoscientific methods; and- To make these methods accessible in a user-friendly manner.

SAGA is written in the C++ programming language. Program code relies on the GNUGeneral Public License. For the most part, this means that SAGA is an open source

project. The source code is readily available. The software is intended and protected toremain open for modifications. The program can be freely distributed. Complementingthe tools, functions, commands that are available in the core SAGA program are

additional capabilities in what are called modules.

Modules are developed with the SAGA API that uses the LGPL or Lesser General Public

License. These modules are optionally published as part of the open source project.

Authors of modules may choose that their modules be unpublished or distributed as

proprietary software.

GIS programs have been in existence for a long time. The term geographic information

system is reportedly first used in a 1965 Northwestern University discussion paperauthored by Michael Dacey and Duane Marble (1965). One of the first GISs that gained

popularity was not computer-based. It was a manual overlay process used for land use

planning in the late 1960s (McHarg, I.L.,1969.Design with nature. Doubleday/NaturalHistory Press, New York).

As computers became more available for scientific analysis, two development roads

emerged for GIS software. These were characterized as grid (or raster) and vector.Eventually, as technological advances in hardware improved computer performance and

expanded storage capability, GIS programs became practical and available integrating

grid and vector functions into the same program, a hybrid GIS.

I would characterize SAGA as a hybrid GIS with emphasis on grid functions that

includes a support integration of vector capability; not strong vector capability butenough for good basic support as well as efficiency gains for users.

There have been many definitions for GIS. What differentiates a GIS from other

information systems is in the spatial or geographic component of the data. The data in a

GIS is geo-referenced. This means the data is tied to locations on the surface of the earth.

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The power of a GIS is the capability to integrate any physical and socio-economic data

that can be related to location on the earths surface for a geographic area and analyzingthis data spatially to address a wide range of issues of a geographic nature.

The U.S. Federal Interagency Coordinating Committee on Digital Cartography (1988)

defined GIS as:

A system of computer hardware, software, and procedures designed to support the

capture, management, manipulation, analysis, modeling and display of spatiallyreferenced data for solving complex planning and management problems. (U.S.

Geological Survey Open-File Report 88-105, A Process for Evaluating Geographic

Information Systems, Technology Exchange Working Group, Technical Report 1.1988.)

GISs have been applied in a wide range of disciplines for a variety of purposes. Some of

these purposes are land use inventories, environmental impact studies, forest

management, water resources management, socio-economic studies.

Traditionally, Public Domain, relative to software, has meant software developed withpublic funds. Since public funds were used for its development, it was only fair and just

to have the product be available gratis to the public (which also includes commercial

entities).

However, for many of us that have been users of public domain software products, we

have come to realize, there is always a price. The price may be in extra time spentlearning exactly how to use the tool. It may not have been designed in the most user-

friendly fashion. Or the price may be in learning how to work around software bugs thateither were never discovered prior to release or were discovered and never fixed due to a

shortage of funds and necessary support. Whatever. And, quite often, the price was, the

developers did not have time to produce a user guide or software manual. This latter

downside can be costly relative to the software being actually used by a user communityor detrimental to the expansion of a user community.

The absence of a user guide or software manual can most easily and most often beignored by users experienced in using the category of software represented by the

program. However, for others, it can become a major obstacle that can eventually result

with the program becoming too costly or frustrating to use except by the most highlymotivated and challenged potential user.

SAGA suffers from some of the downsides of public domain software. Victor Olaya, inhis A Gentle Introduction to SAGA GIS for SAGA version 1.2, produced a wonderful

starting document for individuals having some familiarity with GIS technology. After

using SAGA v1.2 with his guide extensively, I came to accept the Jekyll and Hyde

nature of the SAGA 1.2 software. As I became more familiar with its capabilities I alsorealized that I expected it to be perfect; it is not perfect; there were bugs; there were

inconsistencies between the several operating modes (i.e., grid, shapes, and tables); etc.

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Workspace tab components are modules, data, layers and maps. Interwoven in the

chapters is the use of the Object Properties window and its several tab components(settings, description, attributes, and legend).

Chapter 6 explores how tables are used in SAGA and the edit tools available for use with

tables. Chapter 7 presents some brief How to dos using SAGA to accomplish sometypical GIS functions. Some of these are redundant in that they are included in prior

chapters and some also use modules that are not discussed in detail.

About the Examples

Throughout this guide, I use examples from a small database I developed for Mason

County, Washington, USA. The state of Washington is located in the northwest U.S. on

the Pacific Ocean (Figure 1-1).

Figure 1-1 Location of Washington State, USA.

Mason County is in the western part of the state, west of the Cascade Mountainsbordering south Puget Sound (Figure 1-2).

Figure 1-2 Mason County, Washington State.

The county is 1051 square miles (2722 square kilometers) in total size. About 8.56% of

the total size is water. The population for the county in the 2000 census was 49,405.

Population density is fifty-one people per square mile (twenty people per squarekilometer).

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The single incorporated city and center for county government is Shelton. Un-incorporated communities include Allyn, Belfair, Grapeview, and Skokomish.

A rectangle bounding the county, has approximate corner geographic coordinates

(latitude and longitude and UTM Zone 10 meters) as follows:

Latitude Longitude Easting Northing

NW 47 36 43.8 123 30 39.8 461592 5273322

NE 47 36 43.8 122 47 42.3 515399 5273215

SW 47 04 31.9 123 30 39.8 461201 5213684

SE 47 04 31.9 122 47 42.3 515596 5213577

The SAGA database rectangular window of rows and columns defining Mason County,Washington consists of 585 rows and 539 columns of grid cells. The total number of grid

cells is 315,315; each grid cell is 104.37 meters by 104.37 meters in size.

The grid and shapes data layers used in the examples are not unusual. They are typical

data layer themes one will encounter in a GIS environment. I have chosen to provide

details in how to use the SAGA commands, tools, and functions with these data layers aswell as providing a sample dataset. The best way to learn SAGA using this guide is to

follow the examples using either the sample dataset or your own data layers. Once you

get started you will find that SAGA is easy to use. I would encourage you to use your

own data layers as much as possible.

As I am developing this guide it seems that a day does not pass that I discover a new

feature, procedure, or amazingly fascinating aspect of SAGA. My first exposures to GISsoftware were using grid GISs called PERMITS, GRID, and IMGRID. Even though

SAGA specializes in the grid cell approach to spatial analysis, the functionality and

environment of SAGA is exponentially advanced compared to the early GIS programs Iexperienced.

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Chapter 2 The Graphic User Interface (GUI) and More

Overview

The Graphic User Interface (GUI) in SAGA serves as the interface between SAGA

functions, commands, tools, geographic data and the user. The GUI in SAGA is a

Windows-like implementation.

When you execute SAGA, the initial display may contain windows like Figure 2-1. Whatcan differ will become apparent as I discuss the various sections of the display.

Figure 2-1. The SAGA display window.

The major parts of the GUI are displayed and labeled in Figure 2-2. I will introduce you

to these parts and their associated menus.

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Figure 2-2. The major parts of the SAGA GUI.

Menu Bar

The Menu Bar:The Menu Bar provides access to the basic functions and tools implemented in SAGA.

The default is to display three primary options in the Menu Bar: File, Modules, andWindow. Additional options will be inserted between the Modules and Window titles

depending on actions you have selected. These additional action dependent title options

are Map, Histogram, Scattergram, 3D-View, and Map Layout. In this chapter, I willintroduce you to the various Menu Bar options; many of them will be discussed in more

detail later in this guide.

Clicking on any of the three main titles of the Menu Bar causes a drop-down list ofchoices to appear.

When the Menu Bar displays the three primary menu options as below, the four iconsvisible on the toolbar will be available for selection.

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Here is a cross-reference between the four toolbar icons and their corresponding Menu

Bar commands.

Toolbar Menu Bar

Icon Command

Load

Window: Show Workspace

Window: Show Object Properties

Window: Show Message Window

As you use the various commands and tools in SAGA, as noted above, additional titleswill be added to the Menu Bar. This is also true for the toolbar. There are eight pre-

defined collections of toolbar icons that will appear and disappear as you use SAGA

commands and tools. These toolbar collections are named Map, 3D-View, Map Layout,Table, Diagram, Histogram, Scatterplot, and Standard.

Menu Bar: File

File is the left-most title on the Menu Bar.

When you click on File, this drop-down list of options will appear (see Figure 2-3 below)

Figure 2-3. The File drop-down menu of options.

Introduction to the SAGA project and spatial environment

Before discussing the Project choices, lets talk a little about the project and spatial

environment in SAGA.

There are two general categories of spatial data layers that can be created, managed, andmanipulated with SAGA tools, commands and functions. They are raster or grid data

layers and vector or shapes data layers.

In this guide, I will occasionally use the term raster in place of grid. The two terms are

very interchangeable. Raster is probably most often used today relative to satellite digital

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imagery. It is also used to refer to a grid or matrix because of the close structural

relationship between digital images and grid data layers. Also, the historical reference todigital forms of resource maps comprised of vectors representing points, lines and

polygons in the GIS world has been to refer to them as vector data layers. SAGA will

often refer to vector data layers as shapes data layers. The shape format is a non-

topological vector format developed by the Environmental Systems Research Institute(ESRI). ESRI permits the shape format to be used in non-commercial software. Vector

files used with SAGA are in the shapes format. In this guide, I will use the two terms,

vector and shapes, interchangeably.

In addition to spatial data layers, SAGA uses tables for viewing tabular data related to

shapes data layer features, data distributions, spatial layer color displays, etc.

In a raster or grid data layer, a data value for the attribute featured is developed for every

cell in the matrix of cells making up a study area. Thus, data values in a grid data layer

are for a single attribute; every grid cell in the study area has a value recorded for the

attribute. For example, if the attribute is elevation, every cell in the study area will have avalue identifying the elevation for the grid cell.

The spatial definition of a study area consists of its grid cell size and the matrix or rows

and columns of grid cells covering the area. The grid cell size and shape is the same for

every cell in the study area. The cell size is often referred to as the data resolution for thearea. Once a cell size is defined, a matrix of rows and columns of grid cells spatially

defines the study area based on the extent of the area. This spatial definition is also the

definition for a unique grid system. Over time, the shape of the grid cell for a GISdatabase has been fraught with a variety of technical issues. I would like to introduce you

to some of them as well as to describe the grid cell shape requirement for SAGA 2.0.

Quite often, CPU, memory and peripheral equipment placed restrictions on grid cell

database parameters. The greater the number of grid cells involved in a spatial

manipulation, the longer the execution time, as well as the more memory needed. And, inmany instances, these limitations were translated into smaller databases and larger cell

sizes. Due to the need to keep the cell size large and the overall number of cells small,

and taking into consideration CPU performance and memory availability, early griddatabases were often based on rather large cell sizes compared to today. This resulted

with early grid cell data coding approaches that included percent of cell, majority, and

presence or absence.

An example of percent of cell is where a cell has three different soil types; one occupying

20 percent, one 50 percent, and one 30 percent of the cell. Due to the importance ofretaining as much detail as possible for soil types, the data coding captured the percents

for each soil type. An obvious problem with this approach is coincidence with other

physical and cultural resource data in an overlay function.

A second coding method was the majority method. Using the soil type example above,

the soil type that covers 50 percent of the cell is the majority attribute. Therefore, only the

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majority attribute would be coded for the cell. The downside is that the other two soil

attributes are lost relative to the cell. If one of them was highly susceptible to erosion,being able to consider that trait in spatial analysis is lost.

Presence or absence coding was either a 1 or a 0; a 1 if present and a 0 if absent.

A variation of this was frequency coding. The number of nest sites for Bald Eagles or thenumber of springs in a cell would be entered as the data value.

One of the early methodologies that included a GIS component, defined the grid cellshape using geographic latitude and longitude coordinates; a spherical coordinate system.

Due to the convergence of longitude toward the poles, using latitude and longitude results

with a trapezoidal shaped cell and a cell size that progressively decreases in size as thelatitude increases north in the northern hemisphere or as it increases south in the southern

hemisphere. Defining cell size using a planar cell system resulted with a more

consistently sized cell.

Early GISs depended on line printers for generating hardcopy. This introduced anothertechnical consideration. Most line printers used a rectangular shaped character. If the cell

size was defined using the same width and height proportions, a map produced from aGIS on a line printer could be scaled the same in all directions. Many databases were

developed using a cell size and shape where line printer output was a factor in cell

definition. If a line printer supported a square character set, a square shaped cell could beused.

Another factor for cell shape was the potential error that could result for spatial analysisconducted using grid cells having a height dimension different from its width dimension.

Using a square cell shape would seem to eliminate complexity in spatial analysis basedprogram algorithms.

Today, technology is available that vastly improved the technical environment for GIS

programs. CPUs are fast, memory is inexpensive and fast, mass storage is referred to ingigabytes and not kilobytes, and inkjet printer output is ubiquitous.

SAGA 1.2 supported rectangular and square shaped cells. Some of the modules, however,could not be applied to data layers that used rectangular shaped cells. Only square shaped

cells can be used in SAGA 2.0. The grid file format for SAGA 1.2 was .dgm; for 2.0, the

grid file format was updated to .sgrd. Grid data layers in the SAGA 1.2 .dgm format canbe loaded into SAGA 2.0; however, grid data layers in the SAGA 2.0 .sgrd format cannot

be loaded into SAGA 1.2.

In Chapter 1, I introduced you to my SAGA study area for Mason County, Washington. It

consists of 585 rows and 539 columns of grid cells. The total number of grid cells is

315,315; each grid cell is 104.37 meters by 104.37 meters in size. Not all of the grid cells

are within Mason County as the boundary for the county is irregular in shape. Itsnortheast, east, and southeast edges are defined by irregular shaped water features. Grid

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cells outside of the county, but within the rectangular shape of the row and column matrix

of grid cells, will be coded as no data.

There are two general parts to a vector or shapes data layer. The spatial part defines the

geometry of the features or elements making up the layer. The second part is tabular.

Tabular data is the characteristics or attributes that describe each feature or elementoccurring in the vector or shapes data layer.

Vector or shapes data layers will contain one of three types of geometric features orelements: points, lines, or polygons. The basic geometric component of any vector data

layer is the point. A point location is defined as a single coordinate pair; an x coordinate

and a y coordinate.

A vector or shapes data layer containing points only might be one identifying the location

of nesting sites, wells, auto accidents, etc.

A second category of vector or shapes data layers is one for line or linear features orelements. A line is defined as one or more connected line segments. A line segment has a

beginning point (an x and y coordinate) and an ending point (an x and y coordinate) andlogic connecting the two points with a straight line. One or more line segments may be

connected to define a line. Examples of line vector or shapes data layers include roads,

streams, power lines, etc.

The third category of vector or shapes data layers is polygons. A polygon is three or more

connected line segments enclosing an area. Examples of polygon vector or shapes datalayers include soil types, lakes, census tracts, counties, etc.

Unlike grid data layers that are single dimensional related to attributes, vector or shapes

data layers are multi-dimensional related to attributes. One or more characteristics can be

linked to each feature or element occurring in a vector or shapes data layer. Attribute

tables are used to provide these characteristics.

Vector or shapes data layers are not the primary focus of spatial analysis in SAGA. Most

of the spatial analysis commands and tools in SAGA are applied to grid data layers.Generally, for SAGA spatial analysis commands to involve two or more grid data layers,

the grid data layers must share the same grid system characteristics. The grid layers

within the same grid system have the same grid characteristics if they use the same gridcell size, the same number of rows and columns and they cover the same geographic area.

Therefore, all grid data layers that use the same grid cell size, where each one has the

same number of rows and columns, and cover the same geographic area, will be membersof a unique grid system.

It is important to keep in mind that if spatial analysis commands and tools are to be

applied to two or more grid data layers, the layers must be part of the same grid system asdescribed above. However, if the requirement is a viewing requirement rather than a

spatial analysis function, data layers from different grid systems as well as shapes data

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layers can be included in the same map or map view window. This is discussed in

Chapter 5.

SAGA has no comparable organization, such as a grid system, for vector or shapes data

layers. The criteria for membership in a grid system do not apply to shapes data layers.

File: Project

Project is a SAGA entity (and is actually a SAGA object) for associating one or more

grid systems, grid data layers, shapes data layers and tables that you want linked together.When you want to load a group of related data layers into a SAGA work session, you can

load the project rather than each individual data layer. One or more projects can be

loaded for a work session.

The project file actually is made up of references to data layers, tables, and maps rather

than actually containing data layer files, table files, etc. If you happen to delete a file

from your desktop (or move it to a different storage location from its original one) that is

referenced as part of a project, when you re-load the project the deleted file cannot befound and will be excluded from the list in the Data tab area, and, if it is a data file,

from the thumbnail display in the Layers tab area.

I find that I define projects based on geographic area of coverage, theme, or issue. For

example, I have a project defined for Mason County, Washington. All of the grid andshapes data layers are included in the project. I also have a project defined for a view

shed analysis. The grid and shapes data layers are all related to defining the view shed for

a fire lookout tower on the Olympic Peninsula. Another project I have is defined for gridand shapes data layers used for analyzing mass movement susceptibility. Projects can

help organize large numbers of data layers into logical groupings based on a spatial ortopical theme. A data layer or map can be a member of more than one project.

There is another role for projects in SAGA. A data layer has an associated set of

parameters. These parameters are described in detail in Chapter 4. In general, theseparameters relate to defining the name that SAGA uses for a data layer, how text is

displayed, what colors are used for displaying data, grouping data values for color

emphasis, memory handling, etc. When a data layer is first introduced into SAGA, eitherby a first loading or import, SAGA identifies a set of default parameters for the layer

that become part of the data layer definition. This definition is independent of a

project definition.

Users can modify the data layer defaults. When you define a project, the current data

layer parameters (a project definition) are saved along with the data layer name asbelonging to the project. The project level data layer parameters are independent of the

data layer definitions. Each time you load the project, any modified data layer parameters

will also be re-loaded. The data layer parameters, for both grid and shapes data layers, are

described in Chapter 4.

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data environment will be empty. That is, none of the data layers, maps, and tables from

the previous work session will be re-loaded.

The other option available is Last Opened. This option works with a project.

References to the files in the last project loaded for the work session are stored in the

SAGA configuration file upon exiting SAGA. When the next SAGA work session isinitiated, SAGA will load the data layers, maps, and tables (related to the most recently

loaded project in the previous work session) for the references in the SAGA

configuration file.

When you make a change to the Start Project parameter, you must click on the Apply

button near the bottom of the Object Properties window for the change to be applied.

The Grid File Caching parameters, appearing in the top portion of the Data tab area,

are explained in Chapter 4 of this guide.

The Project menu in the File drop-down menu has three choices that are displayed whenyou hold the mouse pointer or click the label. These choices relate to the SAGA entity

called Project.

File: Project: Load Project

When you select the Load Project option, the dialog window in Figure 2-5 will bedisplayed.

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Figure 2-5. The Load Project dialog window.

In this example, the dialog window has opened my standard project folder (namedProject). If it had not, I could use the normal Windows navigation tools to browse to

the folder containing the project file I want to load. You can see that I have nine projectfiles in this folder.

I can select the project file by clicking on it with my mouse and highlighting it. The name

will automatically be entered in the data entry field for file name. Or, I could key the

project name into the data entry field File name: using the keyboard. If I enter theproject name from the keyboard, I will also include the file format suffix (.sprj).

More than one project can be active or open at a time in a work session. If data layersexist in the Data and Layers tab areas of the Workspace window, when I click on the

Open button, the Close dialog window in Figure 2-6 will be displayed. If no data

layers exist for the current work session, this dialog window will not be displayed.

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Figure 2-6. The Close data sets message.

If I do not want more than one loaded, I can click the Yes button in the Close dialogwindow. All of the current loaded data layers for the work session will be removed and

replaced with the ones associated with the project being loaded.

After clicking the Open button on the Load Project dialog window or the Yes orNo button in the Close dialog window, it may take a few seconds for all the data

layers to be loaded, depending on the size of the project, how many data layers exist for

it, and grid data layer sizes. Once the loading is finished, when I click on the Data orLayers tabs at the bottom of the Workspace, a list of all the currently loaded data layers

will display in the Workspace window or a display of data layer thumbnails will display

in the Layers tab area.

File: Project: Save Project

When you select the Save Project option, all grid systems, grid data layers, shapes datalayers, maps and tables loaded in the current work session will be saved as a project using

the most recently used project name. If a project name has not been used in the work

session, the Save Project command will be grayed out and not available for selection.

This means that, if the Save Project command is available, the current contents for theData and Maps tab areas become the content for the project. In the case where you

have added one or more projects during a work session without replacing previouslyloaded projects, the Save Project command will use the most recently loaded project

name.

Here are a couple examples.

I have initiated a SAGA work session. When the work session is opened, there are no

data layers, maps, or tables that were re-loaded. I use the File: Grid: Load Grid commandto select three grid data layers. After they are loaded, when I view the data layer list in the

Data tab area or the thumbnail display of data layers in the Layers tab area of theWorkspace window, the three data layers will appear. I use the Grid Calculatormoduleto combine two of the grid data layers into a fourth. I rename the new grid data layer and

save it. I now have four grid data layers in the list and I have displayed two as maps; so Ialso have two maps showing in the Maps tab area of the Workspace. I decide to save

the data layers and maps that are in the Data and Maps areas of the Workspace as a

project. I cannot use the Save Project command because it is not available. A projecthas not been used in this work session.

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Since the Save Project command is not available, I should use the Save Project Ascommand described next.

Here is another example. As noted earlier, when you load a project, the grid and shapes

data layers and maps associated with the project will be loaded into the Data andMaps tab areas of the Workspace window. A thumbnail display of the data layers will

appear in the Layers tab area. If you load more than one project and do not remove a

currently open project, the data layers and maps associated with the additional projectwill be added to the already existing data layers and maps in the Workspace.

I start a work session by opening my MasonVisibility project. It is one grid system withthree grid data layers. I next decide to open my Terrain project. I elect to leave the

MasonVisibility project open; that is, I do not remove the project and its associated

data layers and maps. The Data tab area of the Workspace window now displays the

several grid systems and data layers associated with two projects. The Layers tab area

displays the thumbnails for the data layers. I decide to execute the Save Projectcommand. There will not be a dialog window presented. SAGA will automatically save

the two projects currently loaded as one project using the most recently loaded projectname, Terrain. I have not lost the project definition for MasonVisibility but I have re-

defined the original Terrain project.

Be aware that if you use the right-click with the mouse pointer on the Data label in the

Tab area, select the Close command from the pop-up list of options, all of the data

layers and tables currently loaded for the work session will be removed from the worksession. However, this does not erase the most recently used project name. Even though

the data layers related to the project name have gone away, if you use the Save Projectcommand after loading some new data layers, etc., SAGA will still use the most recently

used project name.

File: Project: Save Project As

When the Save Project command was used, whatever was currently loaded in the Data

and Map tab areas of the Workspace window was automatically saved using the most

recently used project name. If you do not want to use the most recently used projectname, you can use the Save Project As command to assign a new project name.

In this example, I have two projects loaded and open. One is called Mason and the otheris Grapeview. I am going to save the two using the project name Mason-Grape to

reflect the combination of data layers for all of Mason County (cell size of 104 meters by

104 meters) and data layers for the Grapeview school district (part of Mason County)with data layers using a cell size of 30 meters by 30 meters. I click on the Save Project

As command. The Save Project dialog window in Figure 2-7 is displayed.

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Figure 2-7. The Save Project dialog window.

In the File name: data field I enter Mason-Grape and click on the Save button. Thenew project file is created and saved. Now, if I want to load all of my data layers for

Mason County as well as the Grapeview school district at the same time I can use theLoad Project command and my Mason-Grape project name and the more than 60 griddata layers and 15 shapes data layers are re-loaded.

File: Project: recent loads

The bottom portion of the Project pop-up list displays a list of recently loaded project

files (up to eight). The most recent are at the top of the list. You can load any of the

project files in the list by clicking the project file name.

This next section of the File drop-down menu is related to loading of data files by

geographic data type category. Of the four options, the first one, Table is the only one

that is not spatial.

File: Table - Overview

SAGA uses tables in many areas. The attributes associated with shapes are stored inDbase table files (.dbf). Custom colors for grid data layers are stored in what are referred

to as color tables. These are usually text files (.txt). There are other SAGA functions that

use and support tables. Chapter 6 explores the way SAGA uses tables.

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File: Table: Load Table

In this example, I will use the Load Table command to load an attribute table thatprovides the attributes for a shapes data layer. The Load Table dialog window displayed

in Figure 2-8 is used to locate and identify the table file for loading.

Figure 2-8. The Load Table dialog window.

The dialog window in Figure 2-8 displays a list of files contained in my Mason folder.

This is the folder where I store all of my data layer files for Mason County. Although it

contains files stored in a variety of file formats, only the text (.txt) and Dbase (.dbf) filesare displayed. If you look in the Files of type: data field you will see that the defaultfile types are Tables (*.txt, *.dbf). The .txt file is the tabs delimited version. These are

the default file types and the only file types supported for this specific command. If you

click on the small black triangle in the right side of the data field, a second option can be

selected called All Files. This option allows you to view a full file list of the contentsfor the folder but you will not be able to load a file in any other format than tabs

delimited text or Dbase.

I am going to load the Dbase file for Mason County transportation called

MCroadsAll.dbf. I can select the .dbf file by clicking on the file name with my mouse

and highlighting it. The name will automatically be entered in the data entry field for filename. Or, I could key in the name into the data entry field using the keyboard. Once the

correct file name is displayed in the File name: field, it is loaded when I click on the

Open button.

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Figure 2-9 shows you what this table file looks like. This is just a small portion of themuch larger table file. Each row in the table relates to a specific spatial feature in the

shapes data layer. This shapes data layer contains records representing roads. The

columns are attributes describing the spatial features.

Figure 2-9. A portion of the MCroadsAll.dbf attribute table file.

The bottom part of the Table pop-up menu displays the last eight loaded table files. The

most recent are at the top of the list. You can load any of the files in the list by clickingon the file name.

File: Shapes - Overview

Shapes refers to vector data in general. Shapes data files can consist of points, lines orpolygons. As part of the overall shapes format, there is an associated attribute table made

up of rows and columns. Each feature or spatial object in a shapes file is referred to by an

attribute row in the table. Each row is made up of columns where each column representsan attribute. Figure 2-9 displays an example of a shapes attribute table.

File: Shapes: Load Shapes

The Load Shapes option is used to load a vector file that is in the shapes (.shp) format

and the associated ancillary file for attributes in the Dbase format (.dbf). When you click

on the Load Shapes command, the dialog window in Figure 2-10 is displayed.

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Figure 2-10. The Load Shapes dialog window.

The dialog window in Figure 2-10 is displaying a list of files contained in my Mason

folder. This is the folder where I store all of my data layer files for the county. Althoughit contains both shapes and grid data layer files, only the shapes data layer file names are

displayed. If you look in the Files of type: data field you will see that the default filetype is ESRI Shape Files (*.shp). This is the default file type and the only file type

supported for this specific command. If you click on the small black triangle in the rightside of the data field, a second option can be selected called All Files. This option

allows you to view the full file list for the folder but you will not be able to load any file

format other than the shape file type.

I can select the shape data layer I want to load by clicking on the file name with my

mouse and highlighting it. If I want to open more than one data layer, I can add additionalselections by using the SHIFT or CONTROL keys when I click on additional file names.

The names will automatically be entered in the data entry field for file name. Or, I could

key in file names in the data entry field using the keyboard. Once the correct file name(s)is displayed in the data field, the file(s) is loaded when I click on the Open button.

File: Shapes: recent loads

The bottom part of the Shapes pop-up menu displays the eight most recently loadedshapes files. The most recent are at the top of the list. You can load any of the files in the

list by clicking on the file name.

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File: T.I.N.

The Triangulated Irregular Network or T.I.N. data structure is a variation of a vectorstructure designed primarily for modeling digital elevation data. It avoids the redundancy

of elevations in a grid data layer and is more efficient for some terrain analysis processes,

such as slope and aspect. It is a terrain model that uses a sheet of continuous, connected

triangular facets based on a Delauncay triangulation of irregularly spaced nodes orobservation points. Unlike the standard digital elevation model or matrix, the TIN allows

extra information to be gathered in areas of complex relief without the need for huge

amounts of redundant data to be gathered from areas of simple relief.

File: T.I.N.: Load T.I.N.

Functions and T.I.N. related modules are still in a developmental stage focusing mainlyon converting from and to raster or vector formats. T.I.N.s can be created from raster or

vector data but, at this time, SAGA does not support storing or loading them directly.

They have to be converted to either grid or shape data layers in order for SAGA to load

them.

File: Grid

As implied by the word grid, a grid is a matrix of rows and columns. The grid cellsdefined by the intersections of the rows and columns are rectangular in shape. Generally,

most grids used in GIS spatial analysis are formed with square grid cells rather than

rectangular shaped ones. Other terms used to refer to grids include raster and pixels.These later terms are most often associated with images such as satellite images or scans

of aerial photography. Pixel is an abbreviation for picture element.

File: Grid: Load Grid

The Load Grid option is used to load a grid data layer file that is in the grid (.sgrd,.dgm) format. The .dgm format was supported in SAGA v1.2 and can be loaded in SAGA

v2.0. The .sgrd format replaced .dgm in SAGA v2.0. When you click on the Load Grid

command, the dialog window in Figure 2-11 is displayed.

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Figure 2-11. The Load Grid dialog window.

The dialog window in Figure 2-11 is displaying a list of files contained in my Mason

folder. All of my data layer files for Mason County are stored in this folder. Although itcontains both shapes and grid data layer files, only the grid data layer file names are

displayed. If you look in the Files of type: data field you will see that the default filetype is Grids (*.sgrd, *.dgm). These are the default file types and the only file types

supported for this specific command. If you click on the small black triangle in the rightside of the data field, a second option can be selected called All Files. This option

allows you to view the full file list for the folder but you will not be able to load any file

formats other than the two grid data layer file types.

I can select the grid data layer I want to load by clicking on the file name with my mouse

and highlighting it. If I want to open more than one data layer, I can add additionalselections by using the SHIFT or CONTROL keys when I click on additional file names.

The names will automatically be entered in the data entry field for file name. Or, I could

key in the name into the data entry field using the keyboard. Once the correct grid datafile name(s) is displayed in the data field, the file is loaded when I click on the Open

button.

The module librariesImport/Export GridsandImport/Export Grids using GDALhavespecial modules designed for importing other grid data formats.

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File: Grid: recent loads

The bottom part of the Grid pop-up menu displays the eight recently loaded grid datalayers. The most recent are at the top of the list. You can load any of the files in the list

by clicking on its name.

File: ExitThe last option on the File drop-down list is Exit. Clicking on Exit will terminate the

current SAGA work session. If, during the work session, you created any new data layers

and they were not saved, SAGA will display the Save Modified Data Objects dialogwindow (Figure 2-12).

Figure 2-12. The Save Modified Data Objects dialog window.

If one or more data files have not been saved, they will be listed in the Save ModifiedData Objects window. For this example, when I clicked on the Exit command to end

the work session, I had one grid data file that had not been saved.

The first option is if I do not want to save the file. In this case, I would leave the check

boxes in the Save all and Save parameter value fields blank and click the Okaybutton on the right side of the window. The work session will end and the new file

unsaved.

There are two ways to retain the unsaved file or files for use in future work sessions. The

Save all parameter can be used. When you click in the box in the value field to the right

of the Save all label, a check will appear in the box. Clicking on the Okay buttoninstructs SAGA to save the file or files listed in the Save Modified Data Objects

window using the path and file name that appears (by default) in the value field to theright of each of the File labels. You can edit the value field for the File parameter.

When you click the Okay button the edited information will be used by SAGA forsaving the file (even if you did not click in the check box for the associated Save

parameter).

The second option is to explicitly save the unsaved data layer or layers. Figure 2-13

shows the Save Modified Data Objects with this option. There are four unsaved data

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layers. Notice that the check box appearing to the right of the Save all label is not

checked.

Figure 2-13. Using the Save parameter in the Save Modified Data Objects dialog window.

Instead, you can see that check boxes to the right of two of the Save parameters for the

four unsaved files have checks in them. This means that when I click on the Okay

button, SAGA will save these two unsaved files using the path and file names in theassociated F

Documents

SAGA2 UserGuide Cimmery 20070401