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1 """ |
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2 This module houses the GEOSCoordSeq object, which is used internally |
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3 by GEOSGeometry to house the actual coordinates of the Point, |
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4 LineString, and LinearRing geometries. |
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5 """ |
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6 from ctypes import c_double, c_uint, byref |
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7 from django.contrib.gis.geos.base import GEOSBase, numpy |
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8 from django.contrib.gis.geos.error import GEOSException, GEOSIndexError |
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9 from django.contrib.gis.geos.libgeos import CS_PTR |
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10 from django.contrib.gis.geos import prototypes as capi |
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11 |
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12 class GEOSCoordSeq(GEOSBase): |
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13 "The internal representation of a list of coordinates inside a Geometry." |
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14 |
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15 ptr_type = CS_PTR |
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16 |
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17 #### Python 'magic' routines #### |
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18 def __init__(self, ptr, z=False): |
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19 "Initializes from a GEOS pointer." |
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20 if not isinstance(ptr, CS_PTR): |
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21 raise TypeError('Coordinate sequence should initialize with a CS_PTR.') |
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22 self._ptr = ptr |
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23 self._z = z |
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24 |
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25 def __iter__(self): |
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26 "Iterates over each point in the coordinate sequence." |
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27 for i in xrange(self.size): |
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28 yield self[i] |
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29 |
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30 def __len__(self): |
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31 "Returns the number of points in the coordinate sequence." |
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32 return int(self.size) |
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33 |
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34 def __str__(self): |
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35 "Returns the string representation of the coordinate sequence." |
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36 return str(self.tuple) |
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37 |
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38 def __getitem__(self, index): |
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39 "Returns the coordinate sequence value at the given index." |
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40 coords = [self.getX(index), self.getY(index)] |
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41 if self.dims == 3 and self._z: |
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42 coords.append(self.getZ(index)) |
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43 return tuple(coords) |
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44 |
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45 def __setitem__(self, index, value): |
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46 "Sets the coordinate sequence value at the given index." |
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47 # Checking the input value |
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48 if isinstance(value, (list, tuple)): |
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49 pass |
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50 elif numpy and isinstance(value, numpy.ndarray): |
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51 pass |
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52 else: |
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53 raise TypeError('Must set coordinate with a sequence (list, tuple, or numpy array).') |
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54 # Checking the dims of the input |
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55 if self.dims == 3 and self._z: |
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56 n_args = 3 |
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57 set_3d = True |
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58 else: |
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59 n_args = 2 |
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60 set_3d = False |
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61 if len(value) != n_args: |
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62 raise TypeError('Dimension of value does not match.') |
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63 # Setting the X, Y, Z |
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64 self.setX(index, value[0]) |
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65 self.setY(index, value[1]) |
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66 if set_3d: self.setZ(index, value[2]) |
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67 |
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68 #### Internal Routines #### |
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69 def _checkindex(self, index): |
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70 "Checks the given index." |
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71 sz = self.size |
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72 if (sz < 1) or (index < 0) or (index >= sz): |
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73 raise GEOSIndexError('invalid GEOS Geometry index: %s' % str(index)) |
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74 |
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75 def _checkdim(self, dim): |
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76 "Checks the given dimension." |
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77 if dim < 0 or dim > 2: |
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78 raise GEOSException('invalid ordinate dimension "%d"' % dim) |
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79 |
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80 #### Ordinate getting and setting routines #### |
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81 def getOrdinate(self, dimension, index): |
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82 "Returns the value for the given dimension and index." |
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83 self._checkindex(index) |
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84 self._checkdim(dimension) |
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85 return capi.cs_getordinate(self.ptr, index, dimension, byref(c_double())) |
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86 |
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87 def setOrdinate(self, dimension, index, value): |
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88 "Sets the value for the given dimension and index." |
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89 self._checkindex(index) |
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90 self._checkdim(dimension) |
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91 capi.cs_setordinate(self.ptr, index, dimension, value) |
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92 |
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93 def getX(self, index): |
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94 "Get the X value at the index." |
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95 return self.getOrdinate(0, index) |
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96 |
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97 def setX(self, index, value): |
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98 "Set X with the value at the given index." |
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99 self.setOrdinate(0, index, value) |
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100 |
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101 def getY(self, index): |
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102 "Get the Y value at the given index." |
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103 return self.getOrdinate(1, index) |
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104 |
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105 def setY(self, index, value): |
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106 "Set Y with the value at the given index." |
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107 self.setOrdinate(1, index, value) |
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108 |
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109 def getZ(self, index): |
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110 "Get Z with the value at the given index." |
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111 return self.getOrdinate(2, index) |
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112 |
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113 def setZ(self, index, value): |
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114 "Set Z with the value at the given index." |
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115 self.setOrdinate(2, index, value) |
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116 |
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117 ### Dimensions ### |
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118 @property |
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119 def size(self): |
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120 "Returns the size of this coordinate sequence." |
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121 return capi.cs_getsize(self.ptr, byref(c_uint())) |
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122 |
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123 @property |
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124 def dims(self): |
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125 "Returns the dimensions of this coordinate sequence." |
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126 return capi.cs_getdims(self.ptr, byref(c_uint())) |
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127 |
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128 @property |
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129 def hasz(self): |
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130 """ |
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131 Returns whether this coordinate sequence is 3D. This property value is |
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132 inherited from the parent Geometry. |
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133 """ |
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134 return self._z |
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135 |
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136 ### Other Methods ### |
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137 def clone(self): |
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138 "Clones this coordinate sequence." |
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139 return GEOSCoordSeq(capi.cs_clone(self.ptr), self.hasz) |
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140 |
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141 @property |
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142 def kml(self): |
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143 "Returns the KML representation for the coordinates." |
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144 # Getting the substitution string depending on whether the coordinates have |
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145 # a Z dimension. |
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146 if self.hasz: substr = '%s,%s,%s ' |
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147 else: substr = '%s,%s,0 ' |
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148 return '<coordinates>%s</coordinates>' % \ |
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149 ''.join([substr % self[i] for i in xrange(len(self))]).strip() |
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150 |
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151 @property |
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152 def tuple(self): |
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153 "Returns a tuple version of this coordinate sequence." |
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154 n = self.size |
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155 if n == 1: return self[0] |
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156 else: return tuple([self[i] for i in xrange(n)]) |