Simple Data Types• Point (2d or 3d)

– Coordinates with attributes

• Polyline (2d or 3d)– Points collected by line segments– 2 lines max per point

• Polygon (2d)– Closed polylines

• Rasters (2d, 3d elevations)– Points in a grid (one attribute or lookup)

• Triangulated Irregular Networks (2d or 3d)– 3 lines max per point

Triangulated Irregular Networks

• TINs

• A “mesh” of triangles

VerticesNodes

Edges, Line Segments, LinksArcs

TINs – Complex but Flexible

Water Resource Management

Improving Environmental Site Management Through the Use of Internet ResourcesAuthors: Gary Whitton, Clayton Cranor, Michael Lilly, David Nyman

More Complex Data Types

• Networks– Related polylines and/or TINs

• Raster Mosaics– Overlapping rasters

• Spatial Databases/Datasets– All types and relationships

• Object Models

Object Data Models

• “Objects” are things

• Objects are connected through “relationships”

• “Methods” are behaviors of objects

AddressNumber

Spatial Data

StreetName

Spatial Data

TerminologyArcDesktop

GeoDB Object model

Database Disk

Layers Feature Dataset

- Database Project Folder

Layer Feature Class

- Table or portion

File

Feature Feature Object Record -

Attribute Field Property Field -

Shapefile Type

Feature ClassType

Class Geometry type in field

-

Additional Slides

Networks

• Streams and rivers– Water supply– Flood prediction– National Hydrology Network

• Transportation (mature):– Freeways, highways, and roads– Ships– Planes

• Disease vectors (developing)

• Natural Resource Management (new)

Network Analysis

• Vertex: Sum of inputs and outputs = 0

• Edge: Has maximum capacity

• Source: Inputs to network

• Sink: Outputs from the network

Global Water Cycle

Complex Features

• Polyline– Rivers & Streams: Connected networks of

“reaches”– Attributes include: quantity of flow

• Polygons– Groups of islands: Hawaii– “Holes”:

• Lakes on surfaces• Islands on lakes