Use the method of Example,Estimating an Irregular AreaSuppose that an environmental contro...

Next we will find the outer area by adding to the inner area all the green squares in Figure that intersect any additional parts of the region. (For the moment, consider the squares with red and blue borders as green squares.) Counting both the orange and green squares, we see that the outer area consists of 55 acres. Therefore, the area we want is somewhere between 24 (the inner area) and 55 (the outer area) acres.

To finalize our estimate, we will average these to get  = 39.5 acres. You can improve this estimate by dividing all of the squares into smaller squares having areas of 14 acre each. The red-bordered square in Figure 1.14(b) shows that by using smaller squares, we would reduce the outer area by not including the two small red squares marked with “a.” Similarly, the blue-bordered square shows that by using smaller squares, we will increase the inner area by including the three small blue-bordered squares marked with “b.” Using this finer grid will lead to a closer estimate of the true area.