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Move mercator transforms to Projection.js.

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The SphericalMercator mixin is not required for coordinate transforms.  Default transforms included whenever Projection.js is included.
This commit is contained in:
Tim Schaub
2012-01-16 22:39:44 -07:00
parent 0e8b3f2ff8
commit 4b949176d3
5 changed files with 75 additions and 125 deletions
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60
lib/OpenLayers/Projection.js
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@@ -195,10 +195,14 @@ OpenLayers.Projection.transform = function(point, source, dest) {
}
if (source.proj && dest.proj) {
point = Proj4js.transform(source.proj, dest.proj, point);
} else if (OpenLayers.Projection.transforms[source.getCode()] &&
OpenLayers.Projection.transforms[source.getCode()][dest.getCode()]) {
OpenLayers.Projection.transforms[source.getCode()][dest.getCode()](point);
}
} else {
var sourceCode = source.getCode();
var destCode = dest.getCode();
var transforms = OpenLayers.Projection.transforms;
if (transforms[sourceCode] && transforms[sourceCode][destCode]) {
transforms[sourceCode][destCode](point);
}
}
}
return point;
};
@@ -209,10 +213,6 @@ OpenLayers.Projection.transform = function(point, source, dest) {
* proj4js is not available:
*
* (code)
* OpenLayers.Projection.addTransform("EPSG:4326", "EPSG:3857",
* OpenLayers.Layer.SphericalMercator.projectForward);
* OpenLayers.Projection.addTransform("EPSG:3857", "EPSG:3857",
* OpenLayers.Layer.SphericalMercator.projectInverse);
* OpenLayers.Projection.addTransform("EPSG:3857", "EPSG:900913",
* OpenLayers.Projection.nullTransform);
* OpenLayers.Projection.addTransform("EPSG:900913", "EPSG:3857",
@@ -222,3 +222,47 @@ OpenLayers.Projection.transform = function(point, source, dest) {
OpenLayers.Projection.nullTransform = function(point) {
return point;
};
/**
* Note: Transforms for web mercator <-> EPSG:4326
* OpenLayers recognizes EPSG:3857, EPSG:900913, EPSG:102113 and EPSG:102100.
* OpenLayers originally started referring to EPSG:900913 as web mercator.
* The EPSG has declared EPSG:3857 to be web mercator.
* ArcGIS 10 recognizes the EPSG:3857, EPSG:102113, and EPSG:102100 as
* equivalent. See http://blogs.esri.com/Dev/blogs/arcgisserver/archive/2009/11/20/ArcGIS-Online-moving-to-Google-_2F00_-Bing-tiling-scheme_3A00_-What-does-this-mean-for-you_3F00_.aspx#12084
*/
(function() {
var pole = 20037508.34;
function inverseMercator(xy) {
xy.x = 180 * xy.x / pole;
xy.y = 180 / Math.PI * (2 * Math.atan(Math.exp((xy.y / pole) * Math.PI)) - Math.PI / 2);
return xy;
}
function forwardMercator(xy) {
xy.x = xy.x * pole / 180;
xy.y = Math.log(Math.tan((90 + xy.y) * Math.PI / 360)) / Math.PI * pole;
return xy;
}
// list of equivalent codes for web mercator
var codes = ["EPSG:900913", "EPSG:3857", "EPSG:102113", "EPSG:102100"];
var add = OpenLayers.Projection.addTransform;
var same = OpenLayers.Projection.nullTransform;
var i, len, code, other, j;
for (i=0, len=codes.length; i<len; ++i) {
code = codes[i];
add("EPSG:4326", code, forwardMercator);
add(code, "EPSG:4326", inverseMercator);
for (j=i+1; j<len; ++j) {
other = codes[j];
add(code, other, same);
add(other, code, same);
}
}
})();