PROJCS>> print(get(21781).as_proj4())
163 | +proj=somerc +lat_0=46.95240555555556 +lon_0=7.439583333333333 \
164 | +k_0=1 +x_0=600000 +y_0=200000 +ellps=bessel \
165 | +towgs84=674.4,15.1,405.3,0,0,0,0 +units=m +no_defs
166 |
167 | """
168 | url = '{prefix}{code}.proj4?download'.format(prefix=EPSG_IO_URL,
169 | code=self.id)
170 | return requests.get(url).text.strip()
171 |
172 | @functools.lru_cache(maxsize=None)
173 | def as_wkt(self):
174 | """
175 | Return the OGC WKT string which corresponds to the CRS.
176 |
177 | For example::
178 |
179 | >>> print(get(27700).as_wkt()) # doctest: +ELLIPSIS
180 | PROJCS["OSGB 1936 / British National Grid",GEOGCS["OSGB 1936...
181 |
182 | """
183 | url = '{prefix}{code}.wkt?download'.format(prefix=EPSG_IO_URL,
184 | code=self.id)
185 | return requests.get(url).text
186 |
187 | @functools.lru_cache(maxsize=None)
188 | def domain_of_validity(self):
189 | """
190 | Return the domain of validity for this CRS as:
191 | (west, east, south, north).
192 |
193 | For example::
194 |
195 | >>> print(get(21781).domain_of_validity())
196 | [5.96, 10.49, 45.82, 47.81]
197 |
198 |
199 | """
200 | # TODO: Generalise interface to return a polygon? (Can we find
201 | # something that uses a polygon instead?)
202 | domain = self.element.find(GML_NS + 'domainOfValidity')
203 | domain_href = domain.attrib[XLINK_NS + 'href']
204 | url = '{prefix}{code}.gml?download'.format(prefix=EPSG_IO_URL,
205 | code=domain_href)
206 | xml = requests.get(url).content
207 | gml = ET.fromstring(xml)
208 |
209 | def extract_bound(tag):
210 | ns = '{http://www.isotc211.org/2005/gmd}'
211 | xpath = './/{ns}EX_GeographicBoundingBox/{ns}{tag}/'.format(
212 | ns=ns,
213 | tag=tag)
214 | bound = gml.find(xpath)
215 | return float(bound.text)
216 |
217 | tags = ('westBoundLongitude', 'eastBoundLongitude',
218 | 'southBoundLatitude', 'northBoundLatitude')
219 | bounds = [extract_bound(tag) for tag in tags]
220 | return bounds
221 |
222 |
223 | class GeodeticCRS(CRS):
224 | """
225 | Represents a single geodetic CRS.
226 |
227 | """
228 |
229 | def __repr__(self):
230 | return ''.format(self=self)
231 |
232 |
233 | class ProjectedCRS(CRS):
234 | """
235 | Represents a single projected CRS.
236 |
237 | """
238 | @property
239 | def base_geodetic_crs(self):
240 | """The :class:`GeodeticCRS` on which this projection is based."""
241 | base = self.element.find(GML_NS + 'baseGeodeticCRS')
242 | href = base.attrib[XLINK_NS + 'href']
243 | return get(href)
244 |
245 | @property
246 | def cartesian_cs(self):
247 | """The :class:`CartesianCS` which describes the coordinate axes."""
248 | cs = self.element.find(GML_NS + 'cartesianCS')
249 | href = cs.attrib[XLINK_NS + 'href']
250 | return get(href)
251 |
252 | def __repr__(self):
253 | return ''.format(self=self)
254 |
255 |
256 | class CompoundCRS(CRS):
257 | """
258 | Represents a single compound CRS.
259 |
260 | """
261 | def __repr__(self):
262 | return ''.format(self=self)
263 |
264 | @functools.lru_cache(maxsize=None)
265 | def get(code):
266 | """
267 | Return an object that corresponds to the given EPSG code.
268 |
269 | Currently supported object types are:
270 | - :class:`GeodeticCRS`
271 | - :class:`ProjectedCRS`
272 | - :class:`CartesianCS`
273 | - :class:`UOM`
274 |
275 | For example::
276 |
277 | >>> print(get(27700))
278 |
279 | >>> print(get('4400-cs'))
280 |
281 | >>> print(get(5973))
282 |
283 |
284 | """
285 | url = '{prefix}{code}.gml?download'.format(prefix=EPSG_IO_URL,
286 | code=code)
287 | xml = requests.get(url).content
288 | root = ET.fromstring(xml)
289 | class_for_tag = {
290 | GML_NS + 'CartesianCS': CartesianCS,
291 | GML_NS + 'GeodeticCRS': GeodeticCRS,
292 | GML_NS + 'ProjectedCRS': ProjectedCRS,
293 | GML_NS + 'CompoundCRS': CompoundCRS,
294 | GML_NS + 'BaseUnit': UOM,
295 | }
296 | if root.tag in class_for_tag:
297 | instance = class_for_tag[root.tag](root)
298 | else:
299 | raise ValueError('Unsupported code type: {}'.format(root.tag))
300 |
301 | return instance
302 |
303 |
304 | if __name__ == '__main__':
305 | import doctest
306 | failure_count, test_count = doctest.testmod()
307 | sys.exit(failure_count)
308 |
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/requirements.txt:
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1 | requests
2 |
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/setup.py:
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1 | # (C) British Crown Copyright 2014, Met Office
2 | #
3 | # This file is part of pyepsg.
4 | #
5 | # pyepsg is free software: you can redistribute it and/or modify it under
6 | # the terms of the GNU Lesser General Public License as published by the
7 | # Free Software Foundation, either version 3 of the License, or
8 | # (at your option) any later version.
9 | #
10 | # pyepsg is distributed in the hope that it will be useful,
11 | # but WITHOUT ANY WARRANTY; without even the implied warranty of
12 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 | # GNU Lesser General Public License for more details.
14 | #
15 | # You should have received a copy of the GNU Lesser General Public License
16 | # along with pyepsg. If not, see .
17 |
18 | from setuptools import setup
19 |
20 | setup(
21 | name='pyepsg',
22 | version='0.5.0',
23 | url='https://github.com/rhattersley/pyepsg',
24 | author='Richard Hattersley',
25 | author_email='rhattersley@gmail.com',
26 | classifiers=['License :: OSI Approved :: '
27 | 'GNU Lesser General Public License v3 (LGPLv3)',
28 | 'Programming Language :: Python :: 3',
29 | 'Programming Language :: Python :: 3.5',
30 | 'Programming Language :: Python :: 3.6',
31 | 'Programming Language :: Python :: 3.7',
32 | 'Programming Language :: Python :: 3.8',
33 | 'Programming Language :: Python :: 3.9',
34 | 'Topic :: Scientific/Engineering :: GIS'],
35 | description='Easy access to the EPSG database via https://epsg.io/',
36 | long_description=open('README.rst').read(),
37 | install_requires=['requests'],
38 | py_modules=['pyepsg'],
39 | )
40 |
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