Area Computation Algorithms
paolo.gph
Global Mapper User
Whats is the algorithm used to compute the area extent of polygon for data in Lat/Long?
Thank you in advance,
Paolo
Thank you in advance,
Paolo
Comments
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Paolo,
For most projected coordinate systems (like UTM), the normal polygon area calculation algorithm (see http://www.wikihow.com/Calculate-the-Area-of-a-Polygon) is used. For very distorted projection systems (like Mercator) and Geographic (lat/lon), the same algorithm is used but by first converting coordinates to lat/lon, cosine-compensating the longitude for latitude, then converting the result in square degrees to square meters based on the current ellipsoid.
Let me know if I can be of further assistance.
Thanks,
Mike
Global Mapper Support
support@globalmapper.com -
can you give the formulas for computing area of the polygon on the ellipsoid?
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A quick Google search turns up a paper giving one approach at http://www.fig.net/pub/fig2010/papers/fs02c%5Cfs02c_freire_vasconcellos_3868.pdf.
Thanks,
Mike
Global Mapper Support
support@globalmapper.com
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