ashatora/openlayers
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Add support for transformation functions without using proj4js, and make

Browse Source 
the SphericalMercator mixin register two transformations to/from EPSG:900913,
EPSG:4326. Thanks to Tim for the feedback and review. (Closes #1210)

This allows us to transform points to/from SphericalMercator 
without proj4js support -- and if other projects need similar functionality, 
they can write their own custom transformation functions rather than 
modifying proj4js to support some custom projection.


git-svn-id: http://svn.openlayers.org/trunk/openlayers@5410 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
This commit is contained in:
crschmidt
2007-12-14 20:45:42 +00:00
parent 9dd5d0e6da
commit a170e3fdf6
6 changed files with 158 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
apidoc_config/Menu.txt
View File

@@ -168,6 +168,8 @@ Group: OpenLayers {
File: Box (no auto-title, OpenLayers/Marker/Box.js)
} # Group: Marker
File: Projection (no auto-title, OpenLayers/Projection.js)
Group: Popup {
File: Popup (OpenLayers/Popup.js)

2
doc_config/Menu.txt
View File

@@ -168,6 +168,8 @@ Group: OpenLayers {
File: Box (no auto-title, OpenLayers/Marker/Box.js)
} # Group: Marker
File: Projection (no auto-title, OpenLayers/Projection.js)
Group: Popup {
File: Popup (OpenLayers/Popup.js)

4
lib/OpenLayers.js
View File

@@ -78,6 +78,7 @@
"Rico/Color.js",
"OpenLayers/Ajax.js",
"OpenLayers/Events.js",
"OpenLayers/Projection.js",
"OpenLayers/Map.js",
"OpenLayers/Layer.js",
"OpenLayers/Icon.js",
@@ -175,8 +176,7 @@
"OpenLayers/Layer/WFS.js",
"OpenLayers/Control/MouseToolbar.js",
"OpenLayers/Control/NavToolbar.js",
"OpenLayers/Control/EditingToolbar.js",
"OpenLayers/Projection.js"
"OpenLayers/Control/EditingToolbar.js"
); // etc.

50
lib/OpenLayers/Layer/SphericalMercator.js
View File

@@ -1,4 +1,5 @@
/** @requires OpenLayers/Layer.js
* @requires OpenLayers/Projection.js
*
* Class: OpenLayers.Layer.SphericalMercator
* A mixin for layers that wraps up the pieces neccesary to have a coordinate
@@ -101,6 +102,55 @@ OpenLayers.Layer.SphericalMercator = {
lat = 180/Math.PI * (2 * Math.atan(Math.exp(lat * Math.PI / 180)) - Math.PI / 2);
return new OpenLayers.LonLat(lon, lat);
},
/**
* Method: projectForward
* Given an object with x and y properties in EPSG:4326, modify the x,y
* properties on the object to be the Spherical Mercator projected
* coordinates.
*
* Parameters:
* point - {Object} An object with x and y properties.
*
* Returns:
* {Object} The point, with the x and y properties transformed to spherical
* mercator.
*/
projectForward: function(point) {
var lonlat = OpenLayers.Layer.SphericalMercator.forwardMercator(point.x, point.y);
point.x = lonlat.lon;
point.y = lonlat.lat;
return point;
},
/**
* Method: projectForward
* Given an object with x and y properties in Spherical Mercator, modify
* the x,y properties on the object to be the unprojected coordinates.
*
* Parameters:
* point - {Object} An object with x and y properties.
*
* Returns:
* {Object} The point, with the x and y properties transformed from
* spherical mercator to unprojected coordinates..
*/
projectInverse: function(point) {
var lonlat = OpenLayers.Layer.SphericalMercator.inverseMercator(point.x, point.y);
point.x = lonlat.lon;
point.y = lonlat.lat;
return point;
}
};
/**
* Note: Two transforms declared
* Transforms from EPSG:4326 to EPSG:900913 and from EPSG:900913 to EPSG:4326
* are set by this class.
*/
OpenLayers.Projection.addTransform("EPSG:4326", "EPSG:900913",
OpenLayers.Layer.SphericalMercator.projectForward);
OpenLayers.Projection.addTransform("EPSG:900913", "EPSG:4326",
OpenLayers.Layer.SphericalMercator.projectInverse);

61
lib/OpenLayers/Projection.js
View File

@@ -6,7 +6,7 @@
* @requires OpenLayers/Util.js
*
* Class: OpenLayers.Projection
* Class for coordinate transformations between coordinate systems.
* Class for coordinate transforms between coordinate systems.
* Depends on the proj4js library. If proj4js is not available,
* then this is just an empty stub.
*/
@@ -101,22 +101,69 @@ OpenLayers.Projection = OpenLayers.Class({
CLASS_NAME: "OpenLayers.Projection"
});
/**
* Property: transforms
* Transforms is an object, with from properties, each of which may
* have a to property. This allows you to define projections without
* requiring support for proj4js to be included.
*
* This object has keys which correspond to a 'source' projection object. The
* keys should be strings, corresponding to the projection.getCode() value.
* Each source projection object should have a set of destination projection
* keys included in the object.
*
* Each value in the destination object should be a transformation function,
* where the function is expected to be passed an object with a .x and a .y
* property. The function should return the object, with the .x and .y
* transformed according to the transformation function.
*
* Note - Properties on this object should not be set directly. To add a
* transform method to this object, use the <addTransform> method. For an
* example of usage, see the OpenLayers.Layer.SphericalMercator file.
*/
OpenLayers.Projection.transforms = {};
/**
* APIMethod: addTransform
* Set a custom transform method between two projections. Use this method in
* cases where the proj4js lib is not available or where custom projections
* need to be handled.
*
* Parameters:
* from - {String} The code for the source projection
* to - {String} the code for the destination projection
* method - {Function} A function that takes a point as an argument and
* transforms that point from the source to the destination projection
* in place. The original point should be modified.
*/
OpenLayers.Projection.addTransform = function(from, to, method) {
if(!OpenLayers.Projection.transforms[from]) {
OpenLayers.Projection.transforms[from] = {};
}
OpenLayers.Projection.transforms[from][to] = method;
};
/**
* APIMethod: transform
* Read data from a string, and return an object whose type depends on the
* subclass.
* Transform a point coordinate from one projection to another. Note that
* the input point is transformed in place.
*
* Parameters:
* point - {object} input horizontal coodinate
* sourceProj - {OpenLayers.Projection} source map coordinate system
* destProj - {OpenLayers.Projection} destination map coordinate system
* point - {{OpenLayers.Geometry.Point> | Object} An object with x and y
* properties representing coordinates in those dimensions.
* sourceProj - {OpenLayers.Projection} Source map coordinate system
* destProj - {OpenLayers.Projection} Destination map coordinate system
*
* Returns:
* point - {object} trasnformed coordinate
* point - {object} A transformed coordinate. The original point is modified.
*/
OpenLayers.Projection.transform = function(point, source, dest) {
if (source.proj && dest.proj) {
point = Proj4js.transform(source.proj, dest.proj, point);
} else if (source && dest &&
OpenLayers.Projection.transforms[source.getCode()] &&
OpenLayers.Projection.transforms[source.getCode()][dest.getCode()]) {
OpenLayers.Projection.transforms[source.getCode()][dest.getCode()](point);
}
return point;
};

51
tests/Layer/test_SphericalMercator.html
View File

@@ -1,9 +1,8 @@
<html>
<head>
<!-- this gmaps key generated for http://openlayers.org/dev/ -->
<script src="../../lib/OpenLayers.js"></script>
<script type="text/javascript">
function test_SphericalMercator_forwardProject(t) {
function test_SphericalMercator_forwardMercator(t) {
t.plan(12);
var arctic = OpenLayers.Layer.SphericalMercator.forwardMercator(0, 85);
var antarctic = OpenLayers.Layer.SphericalMercator.forwardMercator(0, -85);
@@ -32,7 +31,7 @@
t.eq(sw.lon, -20037508.34, "SW lon is correct");
}
function test_sphericalMercator_inverseProject(t) {
function test_sphericalMercator_inverseMercator(t) {
t.plan(4);
var sw = OpenLayers.Layer.SphericalMercator.inverseMercator(-20037508.34, -20037508.34);
var ne = OpenLayers.Layer.SphericalMercator.inverseMercator(20037508.34, 20037508.34);
@@ -42,6 +41,52 @@
t.eq(sw.lat, -85.05112877980659, "Southwest lat correct");
t.eq(ne.lat, 85.05112877980660, "Northeast lat correct");
}
function strToFixed(str, dig) {
if(dig == undefined) {
dig = 5;
}
return str.replace(/(\d+\.\d+)/g, function(match) {
return parseFloat(match).toFixed(dig);
});
}
function test_SphericalMercator_projectForward(t) {
t.plan(1);
var point = new OpenLayers.Geometry.Point(10, 20);
OpenLayers.Layer.SphericalMercator.projectForward(point);
t.eq(strToFixed(point.toString()),
strToFixed("POINT(1113194.9077777779 2273030.9266712805)"),
"point transforms from EPSG:4326 to Spherical Mercator");
}
function test_SphericalMercator_to4326(t) {
t.plan(1);
var point = new OpenLayers.Geometry.Point(1113195, 2273031);
OpenLayers.Layer.SphericalMercator.projectInverse(point);
t.eq(strToFixed(point.toString()),
strToFixed("POINT(10.000000828446318 20.000000618997227)"),
"point transforms from EPSG:4326 to Spherical Mercator");
}
function test_SphericalMercator_addTransform(t) {
// this class should add two methods to the
// OpenLayers.Projection.transforms object
t.plan(4);
var wgs84 = OpenLayers.Projection.transforms["EPSG:4326"];
t.ok(wgs84 instanceof Object, "EPSG:4326 exists in table");
var smerc = OpenLayers.Projection.transforms["EPSG:900913"];
t.ok(smerc instanceof Object, "EPSG:900913 exists in table");
t.ok(wgs84["EPSG:900913"] === OpenLayers.Layer.SphericalMercator.projectForward,
"from EPSG:4326 to EPSG:900913 correctly defined");
t.ok(smerc["EPSG:4326"] === OpenLayers.Layer.SphericalMercator.projectInverse,
"from EPSG:900913 to EPSG:4326 correctly defined");
}
</script>
</head>