Example
Two
Open the map of St. John's, Newfoundland
& Labrador. Calculate
the area of the built up portion of the city (i.e. the pink shaded
area).
Step 1: Work out
the area of one grid square on the map.
Note:
Adjust the pdf file by zooming in or out until each grid square is 2cm in
length.
It is the same as the previous map: 1.0
sq.km.
Step 2: Determine
the number of squares that the object occupies.
In this situation, one could go
from grid square to grid square determing how much the built up
area occupies each square.
i.e. 0.1 of a grid square (5866) + 0.4 (5966) + 0.7 (5967) +
0.7 (6067) + 0.03 (5868) + 0.5 (5968) + 1.0 (6068) +
0.25 (6168)
+ 0.2 (5869) + 0.6 (5969) + 1.0 (6069) +
0.85 (6169)
+ 0.2 (6269) + 0.8
(6070)
+ 0.85 (6170) +
0.2 (6270) + 0.2 (6071) + 0.4 (6171) = 8.98 squares
Step
3: Multiply the number of grid squares that the object occupies
by the area of one grid square.
Hence, 8.98 squares x 1.0 sq.km
= 8.98 sq. km which is the area of downtown St. John's.
Note: Clearly, there is an acceptable
range for the answer due to measuring error. On the government
exam, this would be a multiple choice question. Hence, you would
pick the answer closest to the one that you determined.
