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It may be that you are looking for Z axis data at three levels of Z.

0 = All land
1 = All perimeter enclosed data
2 = All bird locations

If Z data = 0 + 1 + 2 = 3 (bird in perimeter) bird in perimeter counter +1
If Z data = 0 + 2 + 0 = 2 (bird outside perimeter) bird outside perimeter counter +1

If location of bird Z data = 2 read x,y for position on map
If location of bird Z data = 3 read x,y for position on map

Use GPS co-ordinates under overlay of image.

0 level is the number of defined points X, Y. Resolution dependent on GPS resolution.

Finding the edge alone is more complex because you have to test for X+1, X-1, Y+1 and Y-1. If any of them are 0 in the Z axis, it is a perimeter edge.

It should be do-able in Calc. But I'm sure there are better ways.

Hope this helps.

On 2/22/2015 9:15 PM, office76#xt wrote:
Thanks for the replies,
                                           I like the superimposition idea.
If I had a known irregular shape I could map it onto the existing grid. A
brute force approach would be to just make a list of all the X-Y coordinates
in the irregular area, then just search through the entire grid and see if
any coordinates show up in the list, and count them if they do. If the grid
spacing was coarse enough I suppose I could do this on graph paper.
                                           Creating this kind of pre-defined
list with a grid that had a lot of coordinates would be tougher as it would
need to be done programmatically. I think a drawing program where you have a
grid and mark coordinates perhaps as the mouse cursor goes over them could
generate the boundry coordinates of the irregular inner area. The task then
would be to somehow programmatically create a list of all the coordinates
within that area and write them to a list. I've noticed the MS Paint app has
a "fill" function to color in some boundried figure you've drawn with the
mouse. So maybe theres an algorithm out there for this somewhere.

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