8cd50bf768
Also fix a couple of bugs that came up during testing - mostly making sure that elevation, floor and radius are actually set as strings in the XML
322 lines
9.4 KiB
Python
322 lines
9.4 KiB
Python
# -*- coding: utf-8 -*-
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'''
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feedgen.ext.geo_entry
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~~~~~~~~~~~~~~~~~~~
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Extends the FeedGenerator to produce Simple GeoRSS feeds.
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:copyright: 2017, Bob Breznak <bob.breznak@gmail.com>
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:license: FreeBSD and LGPL, see license.* for more details.
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'''
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import numbers
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import warnings
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from lxml import etree
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from feedgen.ext.base import BaseEntryExtension
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class GeoRSSPolygonInteriorWarning(Warning):
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"""
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Simple placeholder for warning about ignored polygon interiors.
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Stores the original geom on a ``geom`` attribute (if required warnings are
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raised as errors).
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"""
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def __init__(self, geom, *args, **kwargs):
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self.geom = geom
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super(GeoRSSPolygonInteriorWarning, self).__init__(*args, **kwargs)
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def __str__(self):
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return '{:d} interiors of polygon ignored'.format(
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len(self.geom.__geo_interface__['coordinates']) - 1 # ignore exterior in count
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)
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class GeoRSSGeometryError(ValueError):
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"""
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Subclass of ValueError for a GeoRSS geometry error
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Only some geometries are supported in Simple GeoRSS, so if not raise an
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error. Offending geometry is stored on the ``geom`` attribute.
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"""
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def __init__(self, geom, *args, **kwargs):
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self.geom = geom
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super(GeoRSSGeometryError, self).__init__(*args, **kwargs)
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def __str__(self):
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return "Geometry of type '{}' not in Point, Linestring or Polygon".format(
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self.geom.__geo_interface__['type']
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)
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class GeoEntryExtension(BaseEntryExtension):
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'''FeedEntry extension for Simple GeoRSS.
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'''
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def __init__(self):
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'''Simple GeoRSS tag'''
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# geometries
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self.__point = None
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self.__line = None
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self.__polygon = None
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self.__box = None
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# additional properties
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self.__featuretypetag = None
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self.__relationshiptag = None
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self.__featurename = None
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# elevation
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self.__elev = None
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self.__floor = None
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# radius
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self.__radius = None
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def extend_file(self, entry):
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'''Add additional fields to an RSS item.
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:param feed: The RSS item XML element to use.
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'''
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GEO_NS = 'http://www.georss.org/georss'
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if self.__point:
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point = etree.SubElement(entry, '{%s}point' % GEO_NS)
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point.text = self.__point
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if self.__line:
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line = etree.SubElement(entry, '{%s}line' % GEO_NS)
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line.text = self.__line
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if self.__polygon:
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polygon = etree.SubElement(entry, '{%s}polygon' % GEO_NS)
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polygon.text = self.__polygon
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if self.__box:
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box = etree.SubElement(entry, '{%s}box' % GEO_NS)
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box.text = self.__box
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if self.__featuretypetag:
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featuretypetag = etree.SubElement(entry, '{%s}featuretypetag' % GEO_NS)
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featuretypetag.text = self.__featuretypetag
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if self.__relationshiptag:
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relationshiptag = etree.SubElement(entry, '{%s}relationshiptag' % GEO_NS)
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relationshiptag.text = self.__relationshiptag
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if self.__featurename:
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featurename = etree.SubElement(entry, '{%s}featurename' % GEO_NS)
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featurename.text = self.__featurename
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if self.__elev:
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elevation = etree.SubElement(entry, '{%s}elev' % GEO_NS)
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elevation.text = str(self.__elev)
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if self.__floor:
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floor = etree.SubElement(entry, '{%s}floor' % GEO_NS)
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floor.text = str(self.__floor)
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if self.__radius:
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radius = etree.SubElement(entry, '{%s}radius' % GEO_NS)
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radius.text = str(self.__radius)
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return entry
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def extend_rss(self, entry):
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return self.extend_file(entry)
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def extend_atom(self, entry):
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return self.extend_file(entry)
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def point(self, point=None):
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'''Get or set the georss:point of the entry.
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:param point: The GeoRSS formatted point (i.e. "42.36 -71.05")
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:returns: The current georss:point of the entry.
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'''
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if point is not None:
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self.__point = point
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return self.__point
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def line(self, line=None):
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'''Get or set the georss:line of the entry
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:param point: The GeoRSS formatted line (i.e. "45.256 -110.45 46.46 -109.48 43.84 -109.86")
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:return: The current georss:line of the entry
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'''
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if line is not None:
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self.__line = line
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return self.__line
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def polygon(self, polygon=None):
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'''Get or set the georss:polygon of the entry
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:param polygon: The GeoRSS formatted polygon (i.e. "45.256 -110.45 46.46 -109.48 43.84 -109.86 45.256 -110.45")
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:return: The current georss:polygon of the entry
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'''
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if polygon is not None:
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self.__polygon = polygon
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return self.__polygon
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def box(self, box=None):
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'''
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Get or set the georss:box of the entry
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:param box: The GeoRSS formatted box (i.e. "42.943 -71.032 43.039 -69.856")
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:return: The current georss:box of the entry
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'''
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if box is not None:
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self.__box = box
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return self.__box
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def featuretypetag(self, featuretypetag=None):
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'''
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Get or set the georss:featuretypetag of the entry
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:param featuretypetag: The GeoRSS feaaturertyptag (e.g. "city")
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:return: The current georss:featurertypetag
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'''
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if featuretypetag is not None:
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self.__featuretypetag = featuretypetag
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return self.__featuretypetag
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def relationshiptag(self, relationshiptag=None):
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'''
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Get or set the georss:relationshiptag of the entry
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:param relationshiptag: The GeoRSS relationshiptag (e.g. "is-centred-at")
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:return: the current georss:relationshiptag
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'''
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if relationshiptag is not None:
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self.__relationshiptag = relationshiptag
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return self.__relationshiptag
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def featurename(self, featurename=None):
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'''
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Get or set the georss:featurename of the entry
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:param featuretypetag: The GeoRSS featurename (e.g. "Footscray")
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:return: the current georss:featurename
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'''
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if featurename is not None:
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self.__featurename = featurename
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return self.__featurename
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def elev(self, elev=None):
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'''
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Get or set the georss:elev of the entry
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:param elev: The GeoRSS elevation (e.g. 100.3)
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:type elev: numbers.Number
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:return: the current georss:elev
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'''
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if elev is not None:
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if not isinstance(elev, numbers.Number):
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raise ValueError("elev tag must be numeric: {}".format(elev))
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self.__elev = elev
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return self.__elev
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def floor(self, floor=None):
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'''
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Get or set the georss:floor of the entry
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:param floor: The GeoRSS floor (e.g. 4)
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:type floor: int
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:return: the current georss:floor
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'''
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if floor is not None:
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if not isinstance(floor, int):
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raise ValueError("floor tag must be int: {}".format(floor))
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self.__floor = floor
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return self.__floor
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def radius(self, radius=None):
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'''
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Get or set the georss:radius of the entry
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:param radius: The GeoRSS radius (e.g. 100.3)
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:type radius: numbers.Number
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:return: the current georss:radius
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'''
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if radius is not None:
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if not isinstance(radius, numbers.Number):
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raise ValueError("radius tag must be numeric: {}".format(radius))
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self.__radius = radius
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return self.__radius
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def geom_from_geo_interface(self, geom):
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'''
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Generate a georss geometry from some Python object with a
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``__geo_interface__`` property (see the `geo_interface specification by
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Sean Gillies`_geointerface )
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Note only a subset of GeoJSON (see `geojson.org`_geojson ) can be easily
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converted to GeoRSS:
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- Point
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- LineString
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- Polygon (if there are holes / donuts in the polygons a warning will be
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generaated
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Other GeoJson types will raise a ``ValueError``.
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.. note:: The geometry is assumed to be x, y as longitude, latitude in
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the WGS84 projection.
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.. _geointerface: https://gist.github.com/sgillies/2217756
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.. _geojson: https://geojson.org/
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:param geom: Geometry object with a __geo_interface__ property
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:return: the formatted GeoRSS geometry
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'''
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geojson = geom.__geo_interface__
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if geojson['type'] not in ('Point', 'LineString', 'Polygon'):
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raise GeoRSSGeometryError(geom)
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if geojson['type'] == 'Point':
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coords = '%f %f'.format(
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geojson['coordinates'][1], # latitude is y
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geojson['coordinates'][0]
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)
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return self.point(coords)
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elif geojson['type'] == 'LineString':
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coords = ' '.join(
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'%f %f'.format(vertex[1], vertex[0])
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for vertex in
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geojson['coordinates']
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)
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return self.line(coords)
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elif geojson['type'] == 'Polygon':
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if len(geojson['coordinates']) > 1:
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warnings.warn(GeoRSSPolygonInteriorWarning(geom))
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coords = ' '.join(
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'%f %f'.format(vertex[1], vertex[0])
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for vertex in
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geojson['coordinates'][0]
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)
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return self.polygon(coords)
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