Equal (ish) areas Map Projection at the Tropics – www.scriptscoop.net

What map projection (non-interrupted) preserves areas well for the entire tropical region? I am thinking of using a Cylindrical Equal Area or a sphere based version of a Cylindrical Equal Area or Mollweide (http://spatialreference.org/ref/esri/54009/). My goal is to minimize area distortion. Well, the projections that you cite are equal area, which mean that the projection does not distort the area. Another popular equal area projection is the sinusoidal projection (it is used with MODIS products). Around the equator, cylindrical equal area and sinusoidal are also quite good in terms of shape (Tissot's indicatrice very close to a circle), so these would be good choices. Now it depends if you like perpendicularity between meridians and parallels (cylindrical), or not (sinusoidal) As @radouxju wrote, you really should use an equal area projection. Interesting is the question of the ratio of the same polygon with shrinked area. I've made test and shift a rudimentray 200x200m patch and the shrinked version 100x100m along the latitude axis. As you see in the results the ration will be something near 25% BUT THERE ARE SOME SERIOUS PROBLEMS The area in LonLat for objects <, 200mx200m is very small and you have to deal with rounding errors? The function that I use to project vectors in 3D to a 2D plane is as follows: The vector is assumed to be on the unit sphere. As for rendering, it depends on if you want to see the stereonet in 3D or not. If you are only interested in a 2D view, I would not suggest using Three.js, instead maybe render to a canvas or SVG/VML. (Visible Geology is written in GWT, so Java, hence the minified code and crazyness. I have rewritten the Stereonet mostly in JavaScript though) Source.


Яндекс.Метрика Рейтинг@Mail.ru Free Web Counter
page counter
Last Modified: April 22, 2016 @ 4:12 am