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391 lines
14 KiB
391 lines
14 KiB
""" |
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This module houses the Point, LineString, LinearRing, and Polygon OGC |
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geometry classes. All geometry classes in this module inherit from |
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GEOSGeometry. |
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""" |
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from ctypes import c_uint, byref |
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from django.contrib.gis.geos.base import GEOSGeometry |
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from django.contrib.gis.geos.coordseq import GEOSCoordSeq |
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from django.contrib.gis.geos.error import GEOSException, GEOSIndexError |
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from django.contrib.gis.geos.libgeos import get_pointer_arr, GEOM_PTR, HAS_NUMPY |
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from django.contrib.gis.geos.prototypes import * |
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if HAS_NUMPY: from numpy import ndarray, array |
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|
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class Point(GEOSGeometry): |
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|
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def __init__(self, x, y=None, z=None, srid=None): |
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""" |
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The Point object may be initialized with either a tuple, or individual |
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parameters. |
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|
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For Example: |
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>>> p = Point((5, 23)) # 2D point, passed in as a tuple |
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>>> p = Point(5, 23, 8) # 3D point, passed in with individual parameters |
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""" |
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|
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if isinstance(x, (tuple, list)): |
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# Here a tuple or list was passed in under the `x` parameter. |
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ndim = len(x) |
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if ndim < 2 or ndim > 3: |
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raise TypeError('Invalid sequence parameter: %s' % str(x)) |
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coords = x |
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elif isinstance(x, (int, float, long)) and isinstance(y, (int, float, long)): |
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# Here X, Y, and (optionally) Z were passed in individually, as parameters. |
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if isinstance(z, (int, float, long)): |
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ndim = 3 |
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coords = [x, y, z] |
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else: |
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ndim = 2 |
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coords = [x, y] |
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else: |
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raise TypeError('Invalid parameters given for Point initialization.') |
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|
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# Creating the coordinate sequence, and setting X, Y, [Z] |
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cs = create_cs(c_uint(1), c_uint(ndim)) |
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cs_setx(cs, 0, coords[0]) |
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cs_sety(cs, 0, coords[1]) |
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if ndim == 3: cs_setz(cs, 0, coords[2]) |
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|
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# Initializing using the address returned from the GEOS |
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# createPoint factory. |
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super(Point, self).__init__(create_point(cs), srid=srid) |
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|
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def __len__(self): |
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"Returns the number of dimensions for this Point (either 0, 2 or 3)." |
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if self.empty: return 0 |
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if self.hasz: return 3 |
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else: return 2 |
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|
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def get_x(self): |
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"Returns the X component of the Point." |
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return self._cs.getOrdinate(0, 0) |
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|
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def set_x(self, value): |
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"Sets the X component of the Point." |
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self._cs.setOrdinate(0, 0, value) |
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|
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def get_y(self): |
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"Returns the Y component of the Point." |
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return self._cs.getOrdinate(1, 0) |
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|
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def set_y(self, value): |
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"Sets the Y component of the Point." |
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self._cs.setOrdinate(1, 0, value) |
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def get_z(self): |
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"Returns the Z component of the Point." |
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if self.hasz: |
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return self._cs.getOrdinate(2, 0) |
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else: |
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return None |
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def set_z(self, value): |
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"Sets the Z component of the Point." |
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if self.hasz: |
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self._cs.setOrdinate(2, 0, value) |
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else: |
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raise GEOSException('Cannot set Z on 2D Point.') |
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# X, Y, Z properties |
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x = property(get_x, set_x) |
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y = property(get_y, set_y) |
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z = property(get_z, set_z) |
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|
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### Tuple setting and retrieval routines. ### |
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def get_coords(self): |
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"Returns a tuple of the point." |
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return self._cs.tuple |
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def set_coords(self, tup): |
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"Sets the coordinates of the point with the given tuple." |
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self._cs[0] = tup |
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# The tuple and coords properties |
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tuple = property(get_coords, set_coords) |
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coords = tuple |
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class LineString(GEOSGeometry): |
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|
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#### Python 'magic' routines #### |
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def __init__(self, *args, **kwargs): |
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""" |
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Initializes on the given sequence -- may take lists, tuples, NumPy arrays |
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of X,Y pairs, or Point objects. If Point objects are used, ownership is |
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_not_ transferred to the LineString object. |
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|
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Examples: |
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ls = LineString((1, 1), (2, 2)) |
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ls = LineString([(1, 1), (2, 2)]) |
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ls = LineString(array([(1, 1), (2, 2)])) |
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ls = LineString(Point(1, 1), Point(2, 2)) |
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""" |
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# If only one argument provided, set the coords array appropriately |
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if len(args) == 1: coords = args[0] |
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else: coords = args |
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if isinstance(coords, (tuple, list)): |
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# Getting the number of coords and the number of dimensions -- which |
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# must stay the same, e.g., no LineString((1, 2), (1, 2, 3)). |
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ncoords = len(coords) |
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if coords: ndim = len(coords[0]) |
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else: raise TypeError('Cannot initialize on empty sequence.') |
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self._checkdim(ndim) |
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# Incrementing through each of the coordinates and verifying |
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for i in xrange(1, ncoords): |
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if not isinstance(coords[i], (tuple, list, Point)): |
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raise TypeError('each coordinate should be a sequence (list or tuple)') |
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if len(coords[i]) != ndim: raise TypeError('Dimension mismatch.') |
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numpy_coords = False |
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elif HAS_NUMPY and isinstance(coords, ndarray): |
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shape = coords.shape # Using numpy's shape. |
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if len(shape) != 2: raise TypeError('Too many dimensions.') |
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self._checkdim(shape[1]) |
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ncoords = shape[0] |
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ndim = shape[1] |
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numpy_coords = True |
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else: |
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raise TypeError('Invalid initialization input for LineStrings.') |
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# Creating a coordinate sequence object because it is easier to |
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# set the points using GEOSCoordSeq.__setitem__(). |
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cs = GEOSCoordSeq(create_cs(ncoords, ndim), z=bool(ndim==3)) |
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for i in xrange(ncoords): |
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if numpy_coords: cs[i] = coords[i,:] |
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elif isinstance(coords[i], Point): cs[i] = coords[i].tuple |
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else: cs[i] = coords[i] |
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# Getting the correct initialization function |
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if kwargs.get('ring', False): |
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func = create_linearring |
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else: |
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func = create_linestring |
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# If SRID was passed in with the keyword arguments |
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srid = kwargs.get('srid', None) |
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# Calling the base geometry initialization with the returned pointer |
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# from the function. |
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super(LineString, self).__init__(func(cs.ptr), srid=srid) |
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def __getitem__(self, index): |
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"Gets the point at the specified index." |
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return self._cs[index] |
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def __setitem__(self, index, value): |
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"Sets the point at the specified index, e.g., line_str[0] = (1, 2)." |
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self._cs[index] = value |
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def __iter__(self): |
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"Allows iteration over this LineString." |
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for i in xrange(len(self)): |
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yield self[i] |
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def __len__(self): |
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"Returns the number of points in this LineString." |
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return len(self._cs) |
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def _checkdim(self, dim): |
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if dim not in (2, 3): raise TypeError('Dimension mismatch.') |
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#### Sequence Properties #### |
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@property |
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def tuple(self): |
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"Returns a tuple version of the geometry from the coordinate sequence." |
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return self._cs.tuple |
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coords = tuple |
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def _listarr(self, func): |
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""" |
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Internal routine that returns a sequence (list) corresponding with |
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the given function. Will return a numpy array if possible. |
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""" |
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lst = [func(i) for i in xrange(len(self))] |
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if HAS_NUMPY: return array(lst) # ARRRR! |
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else: return lst |
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@property |
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def array(self): |
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"Returns a numpy array for the LineString." |
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return self._listarr(self._cs.__getitem__) |
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@property |
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def x(self): |
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"Returns a list or numpy array of the X variable." |
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return self._listarr(self._cs.getX) |
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@property |
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def y(self): |
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"Returns a list or numpy array of the Y variable." |
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return self._listarr(self._cs.getY) |
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@property |
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def z(self): |
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"Returns a list or numpy array of the Z variable." |
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if not self.hasz: return None |
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else: return self._listarr(self._cs.getZ) |
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# LinearRings are LineStrings used within Polygons. |
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class LinearRing(LineString): |
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def __init__(self, *args, **kwargs): |
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"Overriding the initialization function to set the ring keyword." |
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kwargs['ring'] = True # Setting the ring keyword argument to True |
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super(LinearRing, self).__init__(*args, **kwargs) |
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class Polygon(GEOSGeometry): |
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def __init__(self, *args, **kwargs): |
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""" |
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Initializes on an exterior ring and a sequence of holes (both |
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instances may be either LinearRing instances, or a tuple/list |
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that may be constructed into a LinearRing). |
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Examples of initialization, where shell, hole1, and hole2 are |
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valid LinearRing geometries: |
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>>> poly = Polygon(shell, hole1, hole2) |
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>>> poly = Polygon(shell, (hole1, hole2)) |
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Example where a tuple parameters are used: |
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>>> poly = Polygon(((0, 0), (0, 10), (10, 10), (0, 10), (0, 0)), |
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((4, 4), (4, 6), (6, 6), (6, 4), (4, 4))) |
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""" |
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if not args: |
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raise TypeError('Must provide at list one LinearRing instance to initialize Polygon.') |
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# Getting the ext_ring and init_holes parameters from the argument list |
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ext_ring = args[0] |
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init_holes = args[1:] |
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n_holes = len(init_holes) |
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# If initialized as Polygon(shell, (LinearRing, LinearRing)) [for backward-compatibility] |
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if n_holes == 1 and isinstance(init_holes[0], (tuple, list)) and \ |
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(len(init_holes[0]) == 0 or isinstance(init_holes[0][0], LinearRing)): |
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init_holes = init_holes[0] |
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n_holes = len(init_holes) |
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# Ensuring the exterior ring and holes parameters are LinearRing objects |
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# or may be instantiated into LinearRings. |
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ext_ring = self._construct_ring(ext_ring, 'Exterior parameter must be a LinearRing or an object that can initialize a LinearRing.') |
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holes_list = [] # Create new list, cause init_holes is a tuple. |
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for i in xrange(n_holes): |
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holes_list.append(self._construct_ring(init_holes[i], 'Holes parameter must be a sequence of LinearRings or objects that can initialize to LinearRings')) |
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# Why another loop? Because if a TypeError is raised, cloned pointers will |
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# be around that can't be cleaned up. |
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holes = get_pointer_arr(n_holes) |
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for i in xrange(n_holes): holes[i] = geom_clone(holes_list[i].ptr) |
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# Getting the shell pointer address. |
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shell = geom_clone(ext_ring.ptr) |
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# Calling with the GEOS createPolygon factory. |
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super(Polygon, self).__init__(create_polygon(shell, byref(holes), c_uint(n_holes)), **kwargs) |
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def __getitem__(self, index): |
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""" |
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Returns the ring at the specified index. The first index, 0, will |
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always return the exterior ring. Indices > 0 will return the |
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interior ring at the given index (e.g., poly[1] and poly[2] would |
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return the first and second interior ring, respectively). |
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""" |
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if index == 0: |
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return self.exterior_ring |
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else: |
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# Getting the interior ring, have to subtract 1 from the index. |
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return self.get_interior_ring(index-1) |
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def __setitem__(self, index, ring): |
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"Sets the ring at the specified index with the given ring." |
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# Checking the index and ring parameters. |
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self._checkindex(index) |
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if not isinstance(ring, LinearRing): |
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raise TypeError('must set Polygon index with a LinearRing object') |
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# Getting the shell |
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if index == 0: |
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shell = geom_clone(ring.ptr) |
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else: |
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shell = geom_clone(get_extring(self.ptr)) |
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# Getting the interior rings (holes) |
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nholes = len(self)-1 |
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if nholes > 0: |
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holes = get_pointer_arr(nholes) |
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for i in xrange(nholes): |
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if i == (index-1): |
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holes[i] = geom_clone(ring.ptr) |
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else: |
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holes[i] = geom_clone(get_intring(self.ptr, i)) |
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holes_param = byref(holes) |
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else: |
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holes_param = None |
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# Getting the current pointer, replacing with the newly constructed |
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# geometry, and destroying the old geometry. |
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prev_ptr = self.ptr |
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srid = self.srid |
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self._ptr = create_polygon(shell, holes_param, c_uint(nholes)) |
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if srid: self.srid = srid |
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destroy_geom(prev_ptr) |
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def __iter__(self): |
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"Iterates over each ring in the polygon." |
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for i in xrange(len(self)): |
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yield self[i] |
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def __len__(self): |
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"Returns the number of rings in this Polygon." |
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return self.num_interior_rings + 1 |
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def _checkindex(self, index): |
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"Internal routine for checking the given ring index." |
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if index < 0 or index >= len(self): |
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raise GEOSIndexError('invalid Polygon ring index: %s' % index) |
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def _construct_ring(self, param, msg=''): |
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"Helper routine for trying to construct a ring from the given parameter." |
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if isinstance(param, LinearRing): return param |
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try: |
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ring = LinearRing(param) |
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return ring |
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except TypeError: |
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raise TypeError(msg) |
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def get_interior_ring(self, ring_i): |
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""" |
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Gets the interior ring at the specified index, 0 is for the first |
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interior ring, not the exterior ring. |
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""" |
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self._checkindex(ring_i+1) |
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return GEOSGeometry(geom_clone(get_intring(self.ptr, ring_i)), srid=self.srid) |
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#### Polygon Properties #### |
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@property |
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def num_interior_rings(self): |
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"Returns the number of interior rings." |
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# Getting the number of rings |
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return get_nrings(self.ptr) |
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def get_ext_ring(self): |
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"Gets the exterior ring of the Polygon." |
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return GEOSGeometry(geom_clone(get_extring(self.ptr)), srid=self.srid) |
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def set_ext_ring(self, ring): |
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"Sets the exterior ring of the Polygon." |
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self[0] = ring |
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# properties for the exterior ring/shell |
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exterior_ring = property(get_ext_ring, set_ext_ring) |
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shell = exterior_ring |
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@property |
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def tuple(self): |
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"Gets the tuple for each ring in this Polygon." |
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return tuple([self[i].tuple for i in xrange(len(self))]) |
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coords = tuple |
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@property |
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def kml(self): |
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"Returns the KML representation of this Polygon." |
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inner_kml = ''.join(["<innerBoundaryIs>%s</innerBoundaryIs>" % self[i+1].kml |
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for i in xrange(self.num_interior_rings)]) |
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return "<Polygon><outerBoundaryIs>%s</outerBoundaryIs>%s</Polygon>" % (self[0].kml, inner_kml)
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