This past week, I was given an assignment to create buffers of the roads and water within a certain area. A buffer zone is an area that is within a given distance from a map feature. Points, lines, and polygon features can all be buffered. Buffers are used to identify areas surrounding geographic features. When you buffer on a set of features, the output is a set of polygons. These polygons define an inside region, which is an area less than the specified buffer distance from the features of interest. Anything outside of the polygons is the outside region, which is an area more than the specified buffer distance from the features of interest.
I also had some practice with using the overlaying tools, which can be found in the ArcToolbox. Overlays are another common cartographic modeling operation. They are the primary way in which information from two separate themes may be brought together in an analysis. Overlays are most common for polygonal data when we perform a geometric intersection, which results in a new layer with the combined attributes of both initial layers.
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