Creating Spatial Feature Classes Based on Proximity, Overlay, and Attributes - Introducing Geographic Information Systems with ArcGIS - page 404

FIGURE 7-1 Points to be buffered

FIGURE 7-2 Buffers around points

than 20 meters away from streams. That is, the facility had to be within a buffer of the sewers and outside a
buffer of the streams.

Buffering Points
Figure 7-2 shows what a buffer around the set of point features in Figure 7-1 would look like.

You don't see the point features in Figure 7-2 because the point features are not part of the buffer .

In addition to the (geo)graphic portrayal of the buffered areas, an attribute table is created. Since the
production of areas inside the buffer can also create polygons that are outside the buffer, the attribute
table should contain a field that indicates the status of each polygon: inside or outside. For buffering with
geodatabase feature classes, a field is generated that contains the distance used in creating the particular
polygon. If that distance is zero, the area is not within the buffer.

Buffering Lines and Polygons
Line features may be buffered as well. The area of the polygons generated is that covered by the
locus of points that lie within the threshold distance of any point on the line. Examine Figure 7-3
and then Figure 7-4.

You could now see that buffering polygons is merely an extension of the preceding ideas. Again, the
polygons that are buffered, although they are areal features, are not present in the buffer. Examine
Figure 7-5 and then Figure 7-6.

FIGURE 7-3 Lines to be buffered FIGURE 7-4 Buffers around lines