/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/data.py
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revision 1551 by bh, Wed Aug 6 17:21:07 2003 UTC revision 1972 by bh, Mon Nov 24 19:23:08 2003 UTC
# Line 7  Line 7 
7    
8  """Data source abstractions"""  """Data source abstractions"""
9    
10    from __future__ import generators
11    
12  __version__ = "$Revision$"  __version__ = "$Revision$"
13  # $Source$  # $Source$
14  # $Id$  # $Id$
# Line 32  shapelib_shapetypes = {shapelib.SHPT_POL Line 34  shapelib_shapetypes = {shapelib.SHPT_POL
34                         shapelib.SHPT_ARC: SHAPETYPE_ARC,                         shapelib.SHPT_ARC: SHAPETYPE_ARC,
35                         shapelib.SHPT_POINT: SHAPETYPE_POINT}                         shapelib.SHPT_POINT: SHAPETYPE_POINT}
36    
37    #
38    # Raw shape data formats
39    #
40    
41  class Shape:  # Raw data is the same as that returned by the points method.
42    RAW_PYTHON = "RAW_PYTHON"
43    
44      """Represent one shape"""  # Raw data is a shapefile. The Shape object will use the shapeid as the
45    # raw data.
46    RAW_SHAPEFILE = "RAW_SHAPEFILE"
47    
48      def __init__(self, points):  # Raw data in well-known text format
49          self.points = points  RAW_WKT = "RAW_WKT"
         #self.compute_bbox()  
         self.bbox = None  
50    
     def compute_bbox(self):  
         if self.bbox is not None:  
             return self.bbox  
51    
52    class ShapefileShape:
53    
54        """Represent one shape of a shapefile"""
55    
56        def __init__(self, shapefile, shapeid):
57            self.shapefile = shapefile
58            self.shapeid = shapeid
59    
60        def compute_bbox(self):
61            """
62            Return the bounding box of the shape as a tuple (minx,miny,maxx,maxy)
63            """
64          xs = []          xs = []
65          ys = []          ys = []
66          for part in self.points:          for part in self.Points():
67              for x, y in part:              for x, y in part:
68                  xs.append(x)                  xs.append(x)
69                  ys.append(y)                  ys.append(y)
70          self.llx = min(xs)          return (min(xs), min(ys), max(xs), max(ys))
         self.lly = min(ys)  
         self.urx = max(xs)  
         self.ury = max(ys)  
71    
72          self.bbox = (self.llx, self.lly, self.urx, self.ury)      def ShapeID(self):
73            return self.shapeid
         return self.bbox  
74    
75      def Points(self):      def Points(self):
76          return self.points          """Return the coordinates of the shape as a list of lists of pairs"""
77            shape = self.shapefile.read_object(self.shapeid)
78            points = shape.vertices()
79            if self.shapefile.info()[1] == shapelib.SHPT_POINT:
80                points = [points]
81            return points
82    
83        def RawData(self):
84            """Return the shape id to use with the shapefile"""
85            return self.shapeid
86    
87        def Shapefile(self):
88            """Return the shapefile object"""
89            return self.shapefile
90    
91    
92  class ShapeTable(transientdb.AutoTransientTable):  class ShapeTable(transientdb.AutoTransientTable):
# Line 101  class ShapefileStore: Line 124  class ShapefileStore:
124          # safer to always work with absolute paths.          # safer to always work with absolute paths.
125          self.filename = os.path.abspath(filename)          self.filename = os.path.abspath(filename)
126    
         self.shapefile = shapelib.ShapeFile(self.filename)  
127          self.dbftable = table.DBFTable(filename)          self.dbftable = table.DBFTable(filename)
128          self.table = ShapeTable(self, session.TransientDB(), self.dbftable)          self.table = ShapeTable(self, session.TransientDB(), self.dbftable)
129            self._open_shapefile()
130    
131        def _open_shapefile(self):
132            self.shapefile = shapelib.ShapeFile(self.filename)
133          self.numshapes, shapetype, mins, maxs = self.shapefile.info()          self.numshapes, shapetype, mins, maxs = self.shapefile.info()
134          if self.numshapes:          if self.numshapes:
135              self.bbox = mins[:2] + maxs[:2]              self.bbox = mins[:2] + maxs[:2]
# Line 146  class ShapefileStore: Line 171  class ShapefileStore:
171          """          """
172          return self.shapetype          return self.shapetype
173    
174        def RawShapeFormat(self):
175            """Return the raw data format of the shape data, i.e. RAW_SHAPEFILE"""
176            return RAW_SHAPEFILE
177    
178      def NumShapes(self):      def NumShapes(self):
179          """Return the number of shapes in the shape store"""          """Return the number of shapes in the shape store"""
180          return self.numshapes          return self.numshapes
# Line 172  class ShapefileStore: Line 201  class ShapefileStore:
201          """          """
202          return self.bbox          return self.bbox
203    
204      def ShapesInRegion(self, box):      def ShapesInRegion(self, bbox):
205          """Return the ids of the shapes that overlap the box.          """Return an iterable over the shapes that overlap the bounding box.
206    
207          Box is a tuple (left, bottom, right, top) in the coordinate          The bbox parameter should be the bounding box as a tuple in the
208          system used used in the shapefile.          form (minx, miny, maxx, maxy) in the coordinate system of the
209          """          shape store.
210          left, bottom, right, top = box          """
211          return self.shapetree.find_shapes((left, bottom), (right, top))          # Bind a few globals to locals to make it a bit faster
212            cls = ShapefileShape
213            shapefile = self.shapefile
214    
215            left, bottom, right, top = bbox
216            for i in self.shapetree.find_shapes((left, bottom), (right, top)):
217                yield cls(shapefile, i)
218    
219        def AllShapes(self):
220            """Return an iterable over the shapes in the shape store."""
221            for i in xrange(self.NumShapes()):
222                yield ShapefileShape(self.shapefile, i)
223    
224      def Shape(self, index):      def Shape(self, index):
225          """Return the shape with index index"""          """Return the shape with index index"""
226          shape = self.shapefile.read_object(index)          return ShapefileShape(self.shapefile, index)
   
         if self.ShapeType() == SHAPETYPE_POINT:  
             points = [shape.vertices()]  
         else:  
             points = []  
             for poly in shape.vertices():  
                 part = []  
                 for x, y in poly:  
                     part.append((x, y))  
                 points.append(part)  
   
         return Shape(points)  
227    
228    
229    
# Line 250  class DerivedShapeStore: Line 278  class DerivedShapeStore:
278          """          """
279          return self.shapestore.ShapesInRegion(bbox)          return self.shapestore.ShapesInRegion(bbox)
280    
281        def AllShapes(self):
282            """Return an iterable over the shapes in the shape store.
283    
284            This method is simply delegated to the shapestore the
285            DerivedShapeStore was instantiated with.
286            """
287            return self.shapestore.AllShapes()
288    
289      def ShapeType(self):      def ShapeType(self):
290          """Return the type of the shapes in the layer.          """Return the type of the shapes in the layer.
291    
# Line 258  class DerivedShapeStore: Line 294  class DerivedShapeStore:
294          """          """
295          return self.shapestore.ShapeType()          return self.shapestore.ShapeType()
296    
297        def RawShapeFormat(self):
298            """Return the raw data format of the shapes.
299    
300            This method is simply delegated to the shapestore the
301            DerivedShapeStore was instantiated with.
302            """
303            return self.shapestore.RawShapeFormat()
304    
305      def NumShapes(self):      def NumShapes(self):
306          """Return the number of shapes in the shapestore."""          """Return the number of shapes in the shapestore."""
307          return self.shapestore.NumShapes()          return self.shapestore.NumShapes()
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