Spatial Analysis Based on Raster Data Processing - Introducing Geographic Information Systems with ArcGIS - page 519

FIGURE 8-50
on the cardinal directions. Verify (by looking at Pixel value) that the direction in each cell appears
to be the compass direction you would travel from that cell to reach the nearest source cell. The
direction 360 is used to indicate north; the value 0 is indicates those cells that correspond to
the source cells. Use Identify to check out the direction from cell (45,35) to its closest source
cell. _______. Figure 8-50 has arrows drawn to show the value of several cells. Figure 8-51
shows the values in the cells. Use the CellTool toolbar to create the arrows and value numbers.
(You will have to move the direction raster to the top of the T/C to make CellTool work.) 10
Using Cost Distance to Make Direction and Allocation
Rasters
Solve the following problem in a new map. Basically, you are repeating the previous exercise, but using
cost distance instead of Euclidean distance. The distances are calculated differently. In the Euclidean
case they are straight line distances; using cost distance the distances are calculated along a path which
goes from cell center to cell center.
10 CellTool did not work in ArcGIS Version 10.0 for some of those who tested the exercises. See the Color Figures File
for the resulting image should look like.