source: trunk/docs/api/zoo-format-geojson.txt @ 180

Last change on this file since 180 was 174, checked in by jmckenna, 14 years ago

add missing function details

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1.. _api-zoo-format-geojson:
2
3ZOO.Format.GeoJSON
4==================
5
6Read and write GeoJSON.
7
8Properties     
9----------
10
11.. list-table::
12   :widths: 20 50
13   :header-rows: 1
14
15   * - NAME
16     - DESCRIPTION
17   * - :ref:`ZOO.Format.GeoJSON <ZOO.Format.GeoJSON>`
18     - Create a new parser for GeoJSON.
19   * - :ref:`read <read>`
20     - Deserialize a GeoJSON string.
21   * - :ref:`isValidType <isValidType>`
22     - Check if a GeoJSON object is a valid representative of the given type.
23   * - :ref:`parseFeature <parseFeature>`
24     - Convert a feature object from GeoJSON into an ZOO.Feature.
25   * - :ref:`parseGeometry <parseGeometry>`
26     - Convert a geometry object from GeoJSON into an ZOO.Geometry.   
27     
28parseCoords Properties 
29----------------------
30
31.. list-table::
32   :widths: 20 50
33   :header-rows: 1
34
35   * - NAME
36     - DESCRIPTION
37   * - :ref:`parseCoords <parseCoords>`
38     - Object with properties corresponding to the GeoJSON geometry types. 
39     
40parseCoords Functions   
41---------------------
42
43.. list-table::
44   :widths: 12 50
45   :header-rows: 1
46
47   * - NAME
48     - DESCRIPTION
49   * - :ref:`parseCoords.point <parseCoords.point>`
50     - Convert a coordinate array from GeoJSON into an ZOO.Geometry.Point.
51   * - :ref:`parseCoords.multipoint <parseCoords.multipoint>`
52     - Convert a coordinate array from GeoJSON into an ZOO.Geometry.MultiPoint.
53   * - :ref:`parseCoords.linestring <parseCoords.linestring>`
54     - Convert a coordinate array from GeoJSON into an ZOO.Geometry.LineString.
55   * - :ref:`parseCoords.multilinestring <parseCoords.multilinestring>`
56     - Convert a coordinate array from GeoJSON into an ZOO.Geometry.MultiLineString.
57   * - :ref:`parseCoords.polygon <parseCoords.polygon>`
58     - Convert a coordinate array from GeoJSON into an ZOO.Geometry.Polygon. 
59   * - :ref:`parseCoords.multipolygon <parseCoords.multipolygon>`
60     - Convert a coordinate array from GeoJSON into an ZOO.Geometry.MultiPolygon.
61   * - :ref:`parseCoords.box <parseCoords.box>`
62     - Convert a coordinate array from GeoJSON into an ZOO.Geometry.Polygon.
63   * - :ref:`write <write>`
64     - Serialize a feature, geometry, array of features into a GeoJSON string.
65   * - :ref:`createCRSObject <createCRSObject>`
66     - Create the CRS object for an object.     
67     
68extract Properties
69------------------
70
71.. list-table::
72   :widths: 20 50
73   :header-rows: 1
74
75   * - NAME
76     - DESCRIPTION
77   * - :ref:`extract <extract>`
78     - Object with properties corresponding to the GeoJSON types.   
79     
80extract Functions       
81-----------------
82
83.. list-table::
84   :widths: 12 50
85   :header-rows: 1
86
87   * - NAME
88     - DESCRIPTION
89   * - :ref:`extract.feature <extract.feature>`
90     - Return a partial GeoJSON object representing a single feature.
91   * - :ref:`extract.geometry <extract.geometry>`
92     - Return a GeoJSON object representing a single geometry.
93   * - :ref:`extract.point <extract.point>`
94     - Return an array of coordinates from a point.
95   * - :ref:`extract.multipoint <extract.multipoint>`
96     - Return an array of coordinates from a multipoint. 
97   * - :ref:`extract.linestring <extract.linestring>`
98     - Return an array of coordinate arrays from a linestring.
99   * - :ref:`extract.multilinestring <extract.multilinestring>`
100     - Return an array of linestring arrays from a linestring.
101   * - :ref:`extract.polygon <extract.polygon>`
102     - Return an array of linear ring arrays from a polygon.
103   * - :ref:`extract.multipolygon <extract.multipolygon>`
104     - Return an array of polygon arrays from a multipolygon. 
105   * - :ref:`extract.collection <extract.collection>`
106     - Return an array of geometries from a geometry collection.     
107     
108**Functions**   
109 
110.. _ZOO.Format.GeoJSON:                         
111 
112ZOO.Format.GeoJSON     
113  Create a new parser for GeoJSON.
114
115
116  *Parameters*
117
118  ``options {Object}`` An optional object whose properties will be set on this instance.
119 
120.. _read:                           
121 
122read   
123  ::
124 
125    read: function(json,type,filter)
126
127  Deserialize a GeoJSON string.
128
129  *Parameters*
130
131  | ``json {String}`` A GeoJSON string
132  | ``type {String}`` Optional string that determines the structure of the output.  Supported values are "Geometry", "Feature", and "FeatureCollection".  If absent or null, a default of "FeatureCollection" is assumed.
133  | ``filter {Function}`` A function which will be called for every key and value at every level of the final result.  Each value will be replaced by the result of the filter function.  This can be used to reform generic objects into instances of classes, or to transform date strings into Date objects.
134
135  *Returns*
136
137  ``{Object}`` The return depends on the value of the type argument.  If type is "FeatureCollection" (the default),
138  the return will be an array of :ref:`ZOO.Feature <api-zoo-feature>`.  If type is "Geometry", the input json must
139  represent a single geometry, and the return will be an :ref:`ZOO.Geometry <api-zoo-geometry>`.  If type
140  is "Feature", the input json must represent a single feature, and the return will be an :ref:`ZOO.Feature <api-zoo-feature>`.
141 
142.. _isValidType:                             
143 
144isValidType     
145  ::
146 
147    isValidType: function(obj,type)
148
149  Check if a GeoJSON object is a valid representative of the given type.
150
151  *Returns*
152
153  ``{Boolean}`` The object is valid GeoJSON object of the given type.
154 
155.. _parseFeature:                               
156 
157parseFeature   
158  ::
159 
160    parseFeature: function(obj)
161
162  Convert a feature object from GeoJSON into a :ref:`ZOO.Feature <api-zoo-feature>`.
163
164  *Parameters*
165 
166  ``obj {Object}`` An object created from a GeoJSON object
167
168  *Returns*
169
170  :ref:`{ZOO.Feature} <api-zoo-feature>` A feature. 
171 
172.. _parseGeometry:                                 
173 
174parseGeometry   
175  ::
176 
177    parseGeometry: function(obj)
178
179  Convert a geometry object from GeoJSON into a :ref:`ZOO.Geometry <api-zoo-geometry>`.
180
181  *Parameters*
182 
183  ``obj {Object}`` An object created from a GeoJSON object
184
185  *Returns*
186
187  :ref:`{ZOO.Geometry} <api-zoo-geometry>` A geometry.
188 
189**parseCoords Properties**
190
191.. _parseCoords:                                 
192
193parseCoords     
194  Object with properties corresponding to the GeoJSON geometry types. Property
195  values are functions that do the actual parsing.
196 
197**parseCoords Functions**
198
199.. _parseCoords.point:                                 
200
201parseCoords.point       
202  Convert a coordinate array from GeoJSON into a :ref:`ZOO.Geometry.Point <api-zoo-geometry-point>`.
203
204  *Parameters*
205
206  ``array {Object}`` The coordinates array from the GeoJSON fragment.
207
208  *Returns*
209
210  :ref:`{ZOO.Geometry.Point} <api-zoo-geometry-point>` A geometry.
211 
212.. _parseCoords.multipoint:                                   
213 
214parseCoords.multipoint 
215  Convert a coordinate array from GeoJSON into a :ref:`ZOO.Geometry.MultiPoint <api-zoo-geometry-multipoint>`.
216
217  *Parameters*
218 
219  ``array {Object}`` The coordinates array from the GeoJSON fragment.
220
221  *Returns*
222
223  :ref:`{ZOO.Geometry.MultiPoint} <api-zoo-geometry-multipoint>` A geometry.
224 
225.. _parseCoords.linestring:                                     
226 
227parseCoords.linestring 
228  Convert a coordinate array from GeoJSON into a :ref:`ZOO.Geometry.LineString <api-zoo-geometry-linestring>`.
229
230  *Parameters*
231 
232  ``array {Object}`` The coordinates array from the GeoJSON fragment.
233 
234  *Returns*
235
236  :ref:`{ZOO.Geometry.LineString} <api-zoo-geometry-linestring>` A geometry.
237 
238.. _parseCoords.multilinestring:
239 
240parseCoords.multilinestring     
241  Convert a coordinate array from GeoJSON into a :ref:`ZOO.Geometry.MultiLineString <api-zoo-geometry-multilinestring>`.
242
243  *Parameters*
244 
245  ``array {Object}`` The coordinates array from the GeoJSON fragment.
246
247  *Returns*
248
249  :ref:`{ZOO.Geometry.MultiLineString} <api-zoo-geometry-multilinestring>` A geometry.
250 
251.. _parseCoords.polygon: 
252 
253parseCoords.polygon     
254  Convert a coordinate array from GeoJSON into a :ref:`ZOO.Geometry.Polygon <api-zoo-geometry-polygon>`.
255
256  *Parameters*
257 
258  ``array {Object}`` The coordinates array from the GeoJSON fragment.
259
260  *Returns*
261
262  :ref:`{ZOO.Geometry.Polygon} <api-zoo-geometry-polygon>` A geometry.
263 
264.. _parseCoords.multipolygon: 
265
266parseCoords.multipolygon       
267  Convert a coordinate array from GeoJSON into a :ref:`ZOO.Geometry.MultiPolygon <api-zoo-geometry-multipolygon>`.
268 
269  *Parameters*
270
271  ``array {Object}`` The coordinates array from the GeoJSON fragment.
272
273  *Returns*
274
275  :ref:`{ZOO.Geometry.MultiPolygon} <api-zoo-geometry-multipolygon>` A geometry. 
276 
277.. _parseCoords.box: 
278 
279parseCoords.box
280  Convert a coordinate array from GeoJSON into a :ref:`ZOO.Geometry.Polygon <api-zoo-geometry-polygon>`.
281
282  *Parameters*
283 
284  ``array {Object}`` The coordinates array from the GeoJSON fragment.
285
286  *Returns*
287
288  :ref:`{ZOO.Geometry.Polygon} <api-zoo-geometry-polygon>` A geometry. 
289 
290.. _write: 
291 
292write   
293  ::
294 
295    write: function(obj,pretty)
296
297  Serialize a feature, geometry, array of features into a GeoJSON string.
298
299  *Parameters*
300 
301  | ``obj {Object}`` A :ref:`{ZOO.Feature} <api-zoo-feature>`, :ref:`{ZOO.Geometry} <api-zoo-geometry>`, or an array of features.
302  | ``pretty {Boolean}`` Structure the output with newlines and indentation.  Default is false.
303
304  *Returns*
305
306  ``{String}`` The GeoJSON string representation of the input geometry, features, or array of features.
307 
308.. _createCRSObject:   
309 
310createCRSObject
311  ::
312 
313    createCRSObject: function(object)
314
315  Create the CRS object for an object.
316 
317  *Parameters*
318 
319  ``object`` :ref:`{ZOO.Feature} <api-zoo-feature>`
320
321  *Returns*
322
323  ``{Object}`` An object which can be assigned to the crs property of a GeoJSON object.
324 
325**extract Properties**
326
327.. _extract:   
328
329extract
330  Object with properties corresponding to the GeoJSON types. Property values are
331  functions that do the actual value extraction.
332 
333**extract Functions**
334
335.. _extract.feature:   
336
337extract.feature
338  Return a partial GeoJSON object representing a single feature.
339
340
341  *Parameters*
342 
343  ``feature`` :ref:`{ZOO.Feature} <api-zoo-feature>`
344
345  *Returns*
346
347  ``{Object}`` An object representing the point. 
348 
349.. _extract.geometry:     
350 
351extract.geometry       
352  Return a GeoJSON object representing a single geometry.
353
354  *Parameters*
355 
356  ``geometry`` :ref:`{ZOO.Geometry} <api-zoo-geometry>`
357 
358  *Returns*
359
360  ``{Object}`` An object representing the geometry.
361 
362.. _extract.point:       
363 
364extract.point   
365  Return an array of coordinates from a point.
366
367  *Parameters*
368 
369  ``point`` :ref:`{ZOO.Geometry.Point} <api-zoo-geometry-point>`
370
371  *Returns*
372
373  ``{Array}`` An array of coordinates representing the point.
374 
375.. _extract.multipoint:         
376 
377extract.multipoint     
378  Return an array of coordinates from a multipoint.
379
380  *Parameters*
381 
382  ``multipoint`` :ref:`{ZOO.Geometry.MultiPoint} <api-zoo-geometry-multipoint>`
383
384  *Returns*
385
386  ``{Array}`` An array of point coordinate arrays representing the multipoint.
387 
388.. _extract.linestring:           
389 
390extract.linestring     
391  Return an array of coordinate arrays from a linestring.
392
393  *Parameters*
394 
395  ``linestring`` :ref:`{ZOO.Geometry.LineString} <api-zoo-geometry-linestring>`
396
397  *Returns*
398
399  ``{Array}`` An array of coordinate arrays representing the linestring.
400 
401.. _extract.multilinestring:             
402 
403extract.multilinestring
404  Return an array of linestring arrays from a linestring.
405
406  *Parameters*
407 
408  ``multilinestring`` :ref:`{ZOO.Geometry.MultiLineString} <api-zoo-geometry-multilinestring>`
409
410  *Returns*
411
412  ``{Array}`` An array of linestring arrays representing the multilinestring.
413 
414.. _extract.polygon:             
415 
416extract.polygon
417  Return an array of linear ring arrays from a polygon.
418
419  *Parameters*
420 
421  ``polygon`` :ref:`{ZOO.Geometry.Polygon} <api-zoo-geometry-polygon>`
422 
423  *Returns*
424
425  ``{Array}`` An array of linear ring arrays representing the polygon.
426 
427.. _extract.multipolygon:                 
428 
429extract.multipolygon   
430  Return an array of polygon arrays from a multipolygon.
431 
432  *Parameters*
433 
434  ``multipolygon`` :ref:`{ZOO.Geometry.MultiPolygon} <api-zoo-geometry-multipolygon>`
435
436  *Returns*
437
438  ``{Array}`` An array of polygon arrays representing the multipolygon 
439 
440.. _extract.collection: 
441 
442extract.collection     
443  Return an array of geometries from a geometry collection.
444
445  *Parameters*
446
447  ``collection`` :ref:`{ZOO.Geometry.Collection} <api-zoo-geometry-collection>`
448
449  *Returns*
450
451  ``{Array}`` An array of geometry objects representing the geometry collection.
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