PageRenderTime 246ms CodeModel.GetById 120ms app.highlight 14ms RepoModel.GetById 107ms app.codeStats 0ms

/django/contrib/gis/geos/linestring.py

https://code.google.com/p/mango-py/
Python | 152 lines | 99 code | 24 blank | 29 comment | 26 complexity | 59d631ccb59b717bedb326e44263ae5b MD5 | raw file
  1from django.contrib.gis.geos.base import numpy
  2from django.contrib.gis.geos.coordseq import GEOSCoordSeq
  3from django.contrib.gis.geos.error import GEOSException
  4from django.contrib.gis.geos.geometry import GEOSGeometry
  5from django.contrib.gis.geos.point import Point
  6from django.contrib.gis.geos import prototypes as capi
  7
  8class LineString(GEOSGeometry):
  9    _init_func = capi.create_linestring
 10    _minlength = 2
 11
 12    #### Python 'magic' routines ####
 13    def __init__(self, *args, **kwargs):
 14        """
 15        Initializes on the given sequence -- may take lists, tuples, NumPy arrays
 16        of X,Y pairs, or Point objects.  If Point objects are used, ownership is
 17        _not_ transferred to the LineString object.
 18
 19        Examples:
 20         ls = LineString((1, 1), (2, 2))
 21         ls = LineString([(1, 1), (2, 2)])
 22         ls = LineString(array([(1, 1), (2, 2)]))
 23         ls = LineString(Point(1, 1), Point(2, 2))
 24        """
 25        # If only one argument provided, set the coords array appropriately
 26        if len(args) == 1: coords = args[0]
 27        else: coords = args
 28
 29        if isinstance(coords, (tuple, list)):
 30            # Getting the number of coords and the number of dimensions -- which
 31            #  must stay the same, e.g., no LineString((1, 2), (1, 2, 3)).
 32            ncoords = len(coords)
 33            if coords: ndim = len(coords[0])
 34            else: raise TypeError('Cannot initialize on empty sequence.')
 35            self._checkdim(ndim)
 36            # Incrementing through each of the coordinates and verifying
 37            for i in xrange(1, ncoords):
 38                if not isinstance(coords[i], (tuple, list, Point)):
 39                    raise TypeError('each coordinate should be a sequence (list or tuple)')
 40                if len(coords[i]) != ndim: raise TypeError('Dimension mismatch.')
 41            numpy_coords = False
 42        elif numpy and isinstance(coords, numpy.ndarray):
 43            shape = coords.shape # Using numpy's shape.
 44            if len(shape) != 2: raise TypeError('Too many dimensions.')
 45            self._checkdim(shape[1])
 46            ncoords = shape[0]
 47            ndim = shape[1]
 48            numpy_coords = True
 49        else:
 50            raise TypeError('Invalid initialization input for LineStrings.')
 51
 52        # Creating a coordinate sequence object because it is easier to
 53        # set the points using GEOSCoordSeq.__setitem__().
 54        cs = GEOSCoordSeq(capi.create_cs(ncoords, ndim), z=bool(ndim==3))
 55
 56        for i in xrange(ncoords):
 57            if numpy_coords: cs[i] = coords[i,:]
 58            elif isinstance(coords[i], Point): cs[i] = coords[i].tuple
 59            else: cs[i] = coords[i]
 60
 61        # If SRID was passed in with the keyword arguments
 62        srid = kwargs.get('srid', None)
 63
 64        # Calling the base geometry initialization with the returned pointer
 65        #  from the function.
 66        super(LineString, self).__init__(self._init_func(cs.ptr), srid=srid)
 67
 68    def __iter__(self):
 69        "Allows iteration over this LineString."
 70        for i in xrange(len(self)):
 71            yield self[i]
 72
 73    def __len__(self):
 74        "Returns the number of points in this LineString."
 75        return len(self._cs)
 76
 77    def _get_single_external(self, index):
 78        return self._cs[index]
 79
 80    _get_single_internal = _get_single_external
 81
 82    def _set_list(self, length, items):
 83        ndim = self._cs.dims #
 84        hasz = self._cs.hasz # I don't understand why these are different
 85
 86        # create a new coordinate sequence and populate accordingly
 87        cs = GEOSCoordSeq(capi.create_cs(length, ndim), z=hasz)
 88        for i, c in enumerate(items):
 89            cs[i] = c
 90
 91        ptr = self._init_func(cs.ptr)
 92        if ptr:
 93            capi.destroy_geom(self.ptr)
 94            self.ptr = ptr
 95            self._post_init(self.srid)
 96        else:
 97            # can this happen?
 98            raise GEOSException('Geometry resulting from slice deletion was invalid.')
 99
100    def _set_single(self, index, value):
101        self._checkindex(index)
102        self._cs[index] = value
103
104    def _checkdim(self, dim):
105        if dim not in (2, 3): raise TypeError('Dimension mismatch.')
106
107    #### Sequence Properties ####
108    @property
109    def tuple(self):
110        "Returns a tuple version of the geometry from the coordinate sequence."
111        return self._cs.tuple
112    coords = tuple
113
114    def _listarr(self, func):
115        """
116        Internal routine that returns a sequence (list) corresponding with
117        the given function.  Will return a numpy array if possible.
118        """
119        lst = [func(i) for i in xrange(len(self))]
120        if numpy: return numpy.array(lst) # ARRRR!
121        else: return lst
122
123    @property
124    def array(self):
125        "Returns a numpy array for the LineString."
126        return self._listarr(self._cs.__getitem__)
127
128    @property
129    def merged(self):
130        "Returns the line merge of this LineString."
131        return self._topology(capi.geos_linemerge(self.ptr))   
132
133    @property
134    def x(self):
135        "Returns a list or numpy array of the X variable."
136        return self._listarr(self._cs.getX)
137
138    @property
139    def y(self):
140        "Returns a list or numpy array of the Y variable."
141        return self._listarr(self._cs.getY)
142
143    @property
144    def z(self):
145        "Returns a list or numpy array of the Z variable."
146        if not self.hasz: return None
147        else: return self._listarr(self._cs.getZ)
148
149# LinearRings are LineStrings used within Polygons.
150class LinearRing(LineString):
151    _minLength = 4
152    _init_func = capi.create_linearring