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- Finding an Area Covered by Overlapping Polygons
I'm an absolute novice trying to teach myself Manifold, and I've come up against an issue that I need some help with. I'm hoping that somebody can lend a hand.
I have a shape file containing a number of circular polygons that represent tree crowns, and I am trying to calculate the total canopy coverage. The problem is that many of the crowns overlap with each other. I understand that I can find the area of each individual polygon in its row on the data table, but I can't just add all of these areas together, as I don't want to include the overlapping parts multiple times - I just need the area of ground that is covered by tree canopies.
Is there a way to calculate this figure?
All the best,
Based on some novice viewing, and what I would do in a different GIS application, and finding the corresponding ones in Manifold 9, I would think the following two transforms would set you up nicely to get what you're looking for:
Then calculate your area(s)?
Your buffer could have a distance that is 0.0001 cm?
Or make a duplicate of that drawing of the tree canopies and do a "Union Areas".