I want to display a heatmap (png) on a globe in an android app. The heatmap is generated programmatically. The heatmap consists of colored circles. I upload the png to geosserver and display it as wms layer in my app. I use EPSG 4326 as projection to display it on the globe. Unfortunatly, the heatmap is distorted at the poles. It's shown in the picture. How can I fix that?

enter image description here

  • 3
    +1 It's a good question. This image should cause you to reconsider the validity of the original heatmap: the heatmap values always were grossly distorted--and now you can see why. The right solution ought to involve recomputing the heatmap. How to do that depends on what this "heatmap" really is: is it a kernel density estimate or is it something else? (People use the term "heatmap" in different ways.) – whuber Jun 24 '15 at 17:30
  • Try picking an equal area projection and see if that helps. – Ian Turton Jun 24 '15 at 17:41
  • (If anyone wants to explore this in R I recreate it here, requires a github package plus CRAN ones: gist.github.com/mdsumner/a3d2277bae7cd8082302) – mdsumner Jun 25 '15 at 6:44
  • I don't use kernel density estimation. I create the heatmap with php. I draw circles with different amounts of black depending on the weight of the coordinates on a canvas. After that every pixel is assigned a color depending on the grayscale of the pixel. How can I distort the circles for my purpose? – treunel Jun 25 '15 at 7:28
  • What you describe is an algorithm for a kernel density estimate. Do you have the capability to modify the circle radii and densities according to where they are drawn on the map? – whuber Jun 26 '15 at 18:01

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