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I have to digitize one polygon that can accommodate 10million.cubic metre of waste and the study area is completely flat surface. How to determine area?

pauline
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    So you want to create a hole that is 10M m^3 in volume? Well then it could have an area of 1m^2 and a depth of 10M m. Or you could have a polygon of 10M m^2 and a depth of 1m. Could you clarify? – Spacedman Feb 06 '16 at 08:34
  • The area that you arrived will be accurate only when wastes are dumped at equal height in entire polygon. Right? – pauline Feb 06 '16 at 09:44
  • But when we dump the waste it would be like triangular prism. Base area would be irregular polygon. Sorry, If I was wrong. – pauline Feb 06 '16 at 09:46
  • If you're using GIS software, you can just call the getArea() function on the polygon object. Some libraries hsve a getVolume request as well, – Vince Feb 06 '16 at 10:54
  • I was going to dig a hole and fill it with the waste. People don't like big piles of waste. Its still not possible to compute the surface area without knowing the shape of the pile though. Can you edit the question to clarify? Do you want the formula for the area of a cone given its volume and pointy angle? – Spacedman Feb 06 '16 at 13:04

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After digitizing the polygon you know the coordinates of the vertexes from them the area can be calculated:

area = sum(x(i) * x(i+1) - y(i) * y(i+1)) / 2

If you have n points and i = n then use 1 for i+1. The area may be negative depending on the order of points (clockwise or counter clockwise), use the absolute value.

You can find more details here: http://www.mathopenref.com/coordpolygonarea2.html https://en.wikipedia.org/wiki/Shoelace_formula

Zoltan
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