Geography Reference
In-Depth Information
12
45
TABLE 7-4
14
Meter_number
12
45
77
88
23
15
14
88
23
77
15
FIGURE 7-10 Points
indicating parking meters
Overlaying Point Features
Let's suppose that some point features are parking meters, each of which has a number. See Figure 7-10.
In the attribute table, the field Meter_number records this number. See Table 7-4. Also assume that the
polygon feature class “A” you examined previously, depicted zones of the city, and it was desired to
know which parking meters fell into which zones, so that the income from each meter would go to the
correct budget.
Now if the point feature class (see Figure 7-10) is overlaid on the polygon feature class A (see Figure 7-7),
the graphical result of the new point feature class will be the same as Figure 7-10. However, the attribute
table of the new point feature class will look like Table 7-5. Figure 7-11 indicates why, showing as it does
with the dashed lines, the geographic location “A” of Figure 7-7.
Overlaying Line Features
A similar effect occurs if lines are overlaid by polygons. The records associated with the lines in the
output table acquire the attributes of the polygons in which the lines lie. The output line feature class
usually will consist of more lines than the input because when a line from the input crosses a polygon
boundary it is cut, forming a line on either side.
12
45
TABLE 7-5
14
Meter_number
Zone
12
p
88
23
45
p
77
r
77
15
88
s
23
s
15
s
FIGURE 7-11 Points overlaid with
feature class “A”
14
q
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