|
1
|
/* Copyright (c) 2006-2013 by OpenLayers Contributors (see authors.txt for
|
|
2
|
* full list of contributors). Published under the 2-clause BSD license.
|
|
3
|
* See license.txt in the OpenLayers distribution or repository for the
|
|
4
|
* full text of the license. */
|
|
5
|
|
|
6
|
/**
|
|
7
|
* @requires OpenLayers/BaseTypes/Class.js
|
|
8
|
* @requires OpenLayers/Util.js
|
|
9
|
*/
|
|
10
|
|
|
11
|
/**
|
|
12
|
* Namespace: OpenLayers.Projection
|
|
13
|
* Methods for coordinate transforms between coordinate systems. By default,
|
|
14
|
* OpenLayers ships with the ability to transform coordinates between
|
|
15
|
* geographic (EPSG:4326) and web or spherical mercator (EPSG:900913 et al.)
|
|
16
|
* coordinate reference systems. See the <transform> method for details
|
|
17
|
* on usage.
|
|
18
|
*
|
|
19
|
* Additional transforms may be added by using the <proj4js at http://proj4js.org/>
|
|
20
|
* library. If the proj4js library is included, the <transform> method
|
|
21
|
* will work between any two coordinate reference systems with proj4js
|
|
22
|
* definitions.
|
|
23
|
*
|
|
24
|
* If the proj4js library is not included, or if you wish to allow transforms
|
|
25
|
* between arbitrary coordinate reference systems, use the <addTransform>
|
|
26
|
* method to register a custom transform method.
|
|
27
|
*/
|
|
28
|
OpenLayers.Projection = OpenLayers.Class({
|
|
29
|
|
|
30
|
/**
|
|
31
|
* Property: proj
|
|
32
|
* {Object} Proj4js.Proj instance.
|
|
33
|
*/
|
|
34
|
proj: null,
|
|
35
|
|
|
36
|
/**
|
|
37
|
* Property: projCode
|
|
38
|
* {String}
|
|
39
|
*/
|
|
40
|
projCode: null,
|
|
41
|
|
|
42
|
/**
|
|
43
|
* Property: titleRegEx
|
|
44
|
* {RegExp} regular expression to strip the title from a proj4js definition
|
|
45
|
*/
|
|
46
|
titleRegEx: /\+title=[^\+]*/,
|
|
47
|
|
|
48
|
/**
|
|
49
|
* Constructor: OpenLayers.Projection
|
|
50
|
* This class offers several methods for interacting with a wrapped
|
|
51
|
* pro4js projection object.
|
|
52
|
*
|
|
53
|
* Parameters:
|
|
54
|
* projCode - {String} A string identifying the Well Known Identifier for
|
|
55
|
* the projection.
|
|
56
|
* options - {Object} An optional object to set additional properties
|
|
57
|
* on the projection.
|
|
58
|
*
|
|
59
|
* Returns:
|
|
60
|
* {<OpenLayers.Projection>} A projection object.
|
|
61
|
*/
|
|
62
|
initialize: function(projCode, options) {
|
|
63
|
OpenLayers.Util.extend(this, options);
|
|
64
|
this.projCode = projCode;
|
|
65
|
if (typeof Proj4js == "object") {
|
|
66
|
this.proj = new Proj4js.Proj(projCode);
|
|
67
|
}
|
|
68
|
},
|
|
69
|
|
|
70
|
/**
|
|
71
|
* APIMethod: getCode
|
|
72
|
* Get the string SRS code.
|
|
73
|
*
|
|
74
|
* Returns:
|
|
75
|
* {String} The SRS code.
|
|
76
|
*/
|
|
77
|
getCode: function() {
|
|
78
|
return this.proj ? this.proj.srsCode : this.projCode;
|
|
79
|
},
|
|
80
|
|
|
81
|
/**
|
|
82
|
* APIMethod: getUnits
|
|
83
|
* Get the units string for the projection -- returns null if
|
|
84
|
* proj4js is not available.
|
|
85
|
*
|
|
86
|
* Returns:
|
|
87
|
* {String} The units abbreviation.
|
|
88
|
*/
|
|
89
|
getUnits: function() {
|
|
90
|
return this.proj ? this.proj.units : null;
|
|
91
|
},
|
|
92
|
|
|
93
|
/**
|
|
94
|
* Method: toString
|
|
95
|
* Convert projection to string (getCode wrapper).
|
|
96
|
*
|
|
97
|
* Returns:
|
|
98
|
* {String} The projection code.
|
|
99
|
*/
|
|
100
|
toString: function() {
|
|
101
|
return this.getCode();
|
|
102
|
},
|
|
103
|
|
|
104
|
/**
|
|
105
|
* Method: equals
|
|
106
|
* Test equality of two projection instances. Determines equality based
|
|
107
|
* soley on the projection code.
|
|
108
|
*
|
|
109
|
* Returns:
|
|
110
|
* {Boolean} The two projections are equivalent.
|
|
111
|
*/
|
|
112
|
equals: function(projection) {
|
|
113
|
var p = projection, equals = false;
|
|
114
|
if (p) {
|
|
115
|
if (!(p instanceof OpenLayers.Projection)) {
|
|
116
|
p = new OpenLayers.Projection(p);
|
|
117
|
}
|
|
118
|
if ((typeof Proj4js == "object") && this.proj.defData && p.proj.defData) {
|
|
119
|
equals = this.proj.defData.replace(this.titleRegEx, "") ==
|
|
120
|
p.proj.defData.replace(this.titleRegEx, "");
|
|
121
|
} else if (p.getCode) {
|
|
122
|
var source = this.getCode(), target = p.getCode();
|
|
123
|
equals = source == target ||
|
|
124
|
!!OpenLayers.Projection.transforms[source] &&
|
|
125
|
OpenLayers.Projection.transforms[source][target] ===
|
|
126
|
OpenLayers.Projection.nullTransform;
|
|
127
|
}
|
|
128
|
}
|
|
129
|
return equals;
|
|
130
|
},
|
|
131
|
|
|
132
|
/* Method: destroy
|
|
133
|
* Destroy projection object.
|
|
134
|
*/
|
|
135
|
destroy: function() {
|
|
136
|
delete this.proj;
|
|
137
|
delete this.projCode;
|
|
138
|
},
|
|
139
|
|
|
140
|
CLASS_NAME: "OpenLayers.Projection"
|
|
141
|
});
|
|
142
|
|
|
143
|
/**
|
|
144
|
* Property: transforms
|
|
145
|
* {Object} Transforms is an object, with from properties, each of which may
|
|
146
|
* have a to property. This allows you to define projections without
|
|
147
|
* requiring support for proj4js to be included.
|
|
148
|
*
|
|
149
|
* This object has keys which correspond to a 'source' projection object. The
|
|
150
|
* keys should be strings, corresponding to the projection.getCode() value.
|
|
151
|
* Each source projection object should have a set of destination projection
|
|
152
|
* keys included in the object.
|
|
153
|
*
|
|
154
|
* Each value in the destination object should be a transformation function,
|
|
155
|
* where the function is expected to be passed an object with a .x and a .y
|
|
156
|
* property. The function should return the object, with the .x and .y
|
|
157
|
* transformed according to the transformation function.
|
|
158
|
*
|
|
159
|
* Note - Properties on this object should not be set directly. To add a
|
|
160
|
* transform method to this object, use the <addTransform> method. For an
|
|
161
|
* example of usage, see the OpenLayers.Layer.SphericalMercator file.
|
|
162
|
*/
|
|
163
|
OpenLayers.Projection.transforms = {};
|
|
164
|
|
|
165
|
/**
|
|
166
|
* APIProperty: defaults
|
|
167
|
* {Object} Defaults for the SRS codes known to OpenLayers (currently
|
|
168
|
* EPSG:4326, CRS:84, urn:ogc:def:crs:EPSG:6.6:4326, EPSG:900913, EPSG:3857,
|
|
169
|
* EPSG:102113 and EPSG:102100). Keys are the SRS code, values are units,
|
|
170
|
* maxExtent (the validity extent for the SRS) and yx (true if this SRS is
|
|
171
|
* known to have a reverse axis order).
|
|
172
|
*/
|
|
173
|
OpenLayers.Projection.defaults = {
|
|
174
|
"EPSG:4326": {
|
|
175
|
units: "degrees",
|
|
176
|
maxExtent: [-180, -90, 180, 90],
|
|
177
|
yx: true
|
|
178
|
},
|
|
179
|
"CRS:84": {
|
|
180
|
units: "degrees",
|
|
181
|
maxExtent: [-180, -90, 180, 90]
|
|
182
|
},
|
|
183
|
"EPSG:900913": {
|
|
184
|
units: "m",
|
|
185
|
maxExtent: [-20037508.34, -20037508.34, 20037508.34, 20037508.34]
|
|
186
|
}
|
|
187
|
};
|
|
188
|
|
|
189
|
/**
|
|
190
|
* APIMethod: addTransform
|
|
191
|
* Set a custom transform method between two projections. Use this method in
|
|
192
|
* cases where the proj4js lib is not available or where custom projections
|
|
193
|
* need to be handled.
|
|
194
|
*
|
|
195
|
* Parameters:
|
|
196
|
* from - {String} The code for the source projection
|
|
197
|
* to - {String} the code for the destination projection
|
|
198
|
* method - {Function} A function that takes a point as an argument and
|
|
199
|
* transforms that point from the source to the destination projection
|
|
200
|
* in place. The original point should be modified.
|
|
201
|
*/
|
|
202
|
OpenLayers.Projection.addTransform = function(from, to, method) {
|
|
203
|
if (method === OpenLayers.Projection.nullTransform) {
|
|
204
|
var defaults = OpenLayers.Projection.defaults[from];
|
|
205
|
if (defaults && !OpenLayers.Projection.defaults[to]) {
|
|
206
|
OpenLayers.Projection.defaults[to] = defaults;
|
|
207
|
}
|
|
208
|
}
|
|
209
|
if(!OpenLayers.Projection.transforms[from]) {
|
|
210
|
OpenLayers.Projection.transforms[from] = {};
|
|
211
|
}
|
|
212
|
OpenLayers.Projection.transforms[from][to] = method;
|
|
213
|
};
|
|
214
|
|
|
215
|
/**
|
|
216
|
* APIMethod: transform
|
|
217
|
* Transform a point coordinate from one projection to another. Note that
|
|
218
|
* the input point is transformed in place.
|
|
219
|
*
|
|
220
|
* Parameters:
|
|
221
|
* point - {<OpenLayers.Geometry.Point> | Object} An object with x and y
|
|
222
|
* properties representing coordinates in those dimensions.
|
|
223
|
* source - {OpenLayers.Projection} Source map coordinate system
|
|
224
|
* dest - {OpenLayers.Projection} Destination map coordinate system
|
|
225
|
*
|
|
226
|
* Returns:
|
|
227
|
* point - {object} A transformed coordinate. The original point is modified.
|
|
228
|
*/
|
|
229
|
OpenLayers.Projection.transform = function(point, source, dest) {
|
|
230
|
if (source && dest) {
|
|
231
|
if (!(source instanceof OpenLayers.Projection)) {
|
|
232
|
source = new OpenLayers.Projection(source);
|
|
233
|
}
|
|
234
|
if (!(dest instanceof OpenLayers.Projection)) {
|
|
235
|
dest = new OpenLayers.Projection(dest);
|
|
236
|
}
|
|
237
|
if (source.proj && dest.proj) {
|
|
238
|
point = Proj4js.transform(source.proj, dest.proj, point);
|
|
239
|
} else {
|
|
240
|
var sourceCode = source.getCode();
|
|
241
|
var destCode = dest.getCode();
|
|
242
|
var transforms = OpenLayers.Projection.transforms;
|
|
243
|
if (transforms[sourceCode] && transforms[sourceCode][destCode]) {
|
|
244
|
transforms[sourceCode][destCode](point);
|
|
245
|
}
|
|
246
|
}
|
|
247
|
}
|
|
248
|
return point;
|
|
249
|
};
|
|
250
|
|
|
251
|
/**
|
|
252
|
* APIFunction: nullTransform
|
|
253
|
* A null transformation - useful for defining projection aliases when
|
|
254
|
* proj4js is not available:
|
|
255
|
*
|
|
256
|
* (code)
|
|
257
|
* OpenLayers.Projection.addTransform("EPSG:3857", "EPSG:900913",
|
|
258
|
* OpenLayers.Projection.nullTransform);
|
|
259
|
* OpenLayers.Projection.addTransform("EPSG:900913", "EPSG:3857",
|
|
260
|
* OpenLayers.Projection.nullTransform);
|
|
261
|
* (end)
|
|
262
|
*/
|
|
263
|
OpenLayers.Projection.nullTransform = function(point) {
|
|
264
|
return point;
|
|
265
|
};
|
|
266
|
|
|
267
|
/**
|
|
268
|
* Note: Transforms for web mercator <-> geographic
|
|
269
|
* OpenLayers recognizes EPSG:3857, EPSG:900913, EPSG:102113 and EPSG:102100.
|
|
270
|
* OpenLayers originally started referring to EPSG:900913 as web mercator.
|
|
271
|
* The EPSG has declared EPSG:3857 to be web mercator.
|
|
272
|
* ArcGIS 10 recognizes the EPSG:3857, EPSG:102113, and EPSG:102100 as
|
|
273
|
* 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.
|
|
274
|
* For geographic, OpenLayers recognizes EPSG:4326, CRS:84 and
|
|
275
|
* urn:ogc:def:crs:EPSG:6.6:4326. OpenLayers also knows about the reverse axis
|
|
276
|
* order for EPSG:4326.
|
|
277
|
*/
|
|
278
|
(function() {
|
|
279
|
|
|
280
|
var pole = 20037508.34;
|
|
281
|
|
|
282
|
function inverseMercator(xy) {
|
|
283
|
xy.x = 180 * xy.x / pole;
|
|
284
|
xy.y = 180 / Math.PI * (2 * Math.atan(Math.exp((xy.y / pole) * Math.PI)) - Math.PI / 2);
|
|
285
|
return xy;
|
|
286
|
}
|
|
287
|
|
|
288
|
function forwardMercator(xy) {
|
|
289
|
xy.x = xy.x * pole / 180;
|
|
290
|
var y = Math.log(Math.tan((90 + xy.y) * Math.PI / 360)) / Math.PI * pole;
|
|
291
|
xy.y = Math.max(-20037508.34, Math.min(y, 20037508.34));
|
|
292
|
return xy;
|
|
293
|
}
|
|
294
|
|
|
295
|
function map(base, codes) {
|
|
296
|
var add = OpenLayers.Projection.addTransform;
|
|
297
|
var same = OpenLayers.Projection.nullTransform;
|
|
298
|
var i, len, code, other, j;
|
|
299
|
for (i=0, len=codes.length; i<len; ++i) {
|
|
300
|
code = codes[i];
|
|
301
|
add(base, code, forwardMercator);
|
|
302
|
add(code, base, inverseMercator);
|
|
303
|
for (j=i+1; j<len; ++j) {
|
|
304
|
other = codes[j];
|
|
305
|
add(code, other, same);
|
|
306
|
add(other, code, same);
|
|
307
|
}
|
|
308
|
}
|
|
309
|
}
|
|
310
|
|
|
311
|
// list of equivalent codes for web mercator
|
|
312
|
var mercator = ["EPSG:900913", "EPSG:3857", "EPSG:102113", "EPSG:102100"],
|
|
313
|
geographic = ["CRS:84", "urn:ogc:def:crs:EPSG:6.6:4326", "EPSG:4326"],
|
|
314
|
i;
|
|
315
|
for (i=mercator.length-1; i>=0; --i) {
|
|
316
|
map(mercator[i], geographic);
|
|
317
|
}
|
|
318
|
for (i=geographic.length-1; i>=0; --i) {
|
|
319
|
map(geographic[i], mercator);
|
|
320
|
}
|
|
321
|
|
|
322
|
})();
|