We used the terrain analysis tools available in both th #D and Spatial Analyst extensions using elevation data from NC LIDAR Digital Elevation Models (DEMs) which have a a 20ft by 20ft sample grid. We generated four raster layers:
-Hillshade (shaded relief)
-Aspect model (direction in degrees)
-Slope model (steepnes in degrees)
-Contour lines (isolines for elevation)
To render a 3D effect, we overlyed each layer on top of the Hillshade layer and set transparenct for the top layer at 40%, then adjusted transparency for best appearance as we zoomed in and out. For some layers zooming in to a larger map scale gave a better sense of the data. This was especially true for the Aspect model.
-Hillshade (shaded relief)
-Aspect model (direction in degrees)
-Slope model (steepnes in degrees)
-Contour lines (isolines for elevation)
To render a 3D effect, we overlyed each layer on top of the Hillshade layer and set transparenct for the top layer at 40%, then adjusted transparency for best appearance as we zoomed in and out. For some layers zooming in to a larger map scale gave a better sense of the data. This was especially true for the Aspect model.
The Elevation model map above and the Aspect model map below are at the same scale.
Information about aspect is difficult to read until you zoom in to an appropriate scale of resolution where the 20 foot raster cells become sufficiently distinguishable.
To see the relationship between the Slope model raster shading and 40 foot conout interval lines required zooming in to a scale where space appeared between contours. You can see where on the steep slopes indicated by red shading, the contour lines are closer together than on the less steep green areas.
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