On Wed, 21 Jan 2004 09:47:47 -0000, Warren Vick, Europa Technologies Ltd. <[EMAIL PROTECTED]> wrote:

The thing I'm not sure about is using cos(). Cosine yields a value between
-1 and 1 which means the area of each cell is either the same, or reduced
(assuming the -ve is ignored for an area calculation). However, doesn't the
effective surface area of a grid cell get bigger with increasing slope?.
E.g. consider a cell with a slope of 45 degrees on the horizontal axis...
would that not yield an area of A*A*sqrt(2)? With sqrt(2) being about twice
cos(45), the calculation will be well out.

Of course, I made a mistake. Using Cosine is right, but the equation should look like this:


AREA = SUM((A/COS(SLOPE)) * A)

Accept my apology, please.

Jaromir

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