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3

The answer to radouxju's question depends on the shape of the pixel when projected onto the ellipsoid. If the coordinate system of the raster is longitude and latitude, then the pixel is a rhumb line rectangle and whuber's answer can be used, or, more generally, you can use the formula for a polygon whose edges are rhumb lines. If the coordinate system is ...


9

There is a relatively simple exact formula for the area of any spherical quadrangle bounded by parallels (lines of latitude) and meridians (lines of longitude). It can be derived straightforwardly using basic properties of the ellipse (of major axis a and minor axis b) that is rotated around its minor axis to produce the ellipsoid. (The derivation makes a ...


0

I found this post when trying to do something similar, determining the parish with the biggest area within a fishnet polygon. Since this hasn’t been answered I present the solution I adapted in ArcGIS 10.2. Using the command “Tabulate Intersection Overlay” the total of area of each parish with a fishnet polygon is determined (area and percentage). Using ...


2

What you should look for is called 'Map Matching'. I've opened sourced my idea based on GraphHopper very recently here so it is still in a VERY early shape, please give feedback via providing data or creating issues etc.


3

According to this maths is fun page, or the wikipedia steridian article, you will discover that there are 12.56637 steradians in a sphere. So, if you take the area of the earth to be, 510,072,000 sq km, then, given your area of 8.101249039703731e-8, and plugging in these numbers, you get: 8.101249039703731e-8 / 12.56637 * 510,072,000 = 3.288 km². or in ...


0

It seems your code sums the area covered by the polygons. Instead of relying on a field that may or may not exist, and may or may not be correct you can get the area of the shapes at runtime: Assuming that the feature class is in an appropriate spatial reference to sum the area: def MySub(TotalArea1): TotalArea = 0.0 with ...


1

In general, there is more support for the geometry than the geography data type, see function comparison matrix. For your type of query, classic point in polygon, I think you can use the geometry datatype, setting the spatial reference ID (SRID) to 4326 (lat/lon). See, this thread on the difference between geography and geometry for more info. The gist ...



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