Cartographic modeling

In this exercise, we will create a basic map of land cover with a descriptive graph embedded in the

map.

1. Open a classified land cover raster.

2. Let’s add some additional data to provide more context. Download, extract, and add the

following shapefiles:

a. http://www.diva-gis.org/data/rds/NPL_rds.zip

b. http://gadm.org/data/shp/NPL_adm.zip

3. Label the towns and district boundaries by double-clicking on the administrative layer. Under

the “Labels” tab, select “Label features in this layer” and identify “NAME_03” as the

attribute to label.

4. Also, remove the fill of the administrative features layer.

5. By now, the map looks a little busy!

6. Let’s pick some alternative colors. Go to http://colorbrewer2.org/.

7. We need to get colors for 9 classes. Select “9” as the number of classes. In the “Nature of

your data” area, select “Qualitative”—in our case, the land cover classes are qualitatively

different from each other. Then select one of the color schemes.

8. We are interested in the RGB codes. Write them down and assign them to the color classes of

the raster.

9. The map still looks a little hectic – mostly because there are 9 classes of color. Also, these

colors were arbitrarily assigned to classes – ideally, certain colors would be used to represent

known land cover classes (blue for water, green for forest, etc.). However, it’s now much

easier to see the roads and administrative boundaries layers. Now let’s quantify the relative

coverage of each of these classes. Under “View” select “Graphs” “Create”.

10. Match the selections below, or chose other options for displaying the number of cells in each

class of the raster layer.

11. We are nearly ready to export the map. Click “Layout View” under “View”. Adjust the page

layout and size depending on the section of the raster layer you wish to display. Also, add the

other key map features (scale, north arrow, legend, etc.).

12. Now right-click on the graph and select “Add to layout”.

13. To save the map, click on “File” “Export Map”. Name the file, choose a folder to save it,

and save as a PDF.

14. Depending on the print quality you seek you may wish to change the resolution. Note that this

is only relevant for raster files. If your map only had vector layers and you export as a PDF

file, the output will remain a vector-based image.

15. If you intend to invest substantial energy in the production of a map, it is often useful to

export the map as an “SVG” file, and edit it in Adobe Illustrator, or the excellent open source

alternative: Inkscape - http://inkscape.org/.