/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/data.py
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revision 1261 by jonathan, Fri Jun 20 14:14:42 2003 UTC revision 1535 by bh, Fri Aug 1 14:27:13 2003 UTC
# Line 12  __version__ = "$Revision$" Line 12  __version__ = "$Revision$"
12  # $Id$  # $Id$
13    
14  import os  import os
 import warnings  
15  import weakref  import weakref
16    from math import ceil, log
17    
18  import shapelib  import shapelib
19    import shptree
20  import table  import table
21  import transientdb  import transientdb
22    
23  from Thuban import _  from Thuban import _
24    
25    # Shape type constants
26    SHAPETYPE_POLYGON = "polygon"
27    SHAPETYPE_ARC = "arc"
28    SHAPETYPE_POINT = "point"
29    
30    # mapping from shapelib shapetype constants to our constants
31    shapelib_shapetypes = {shapelib.SHPT_POLYGON: SHAPETYPE_POLYGON,
32                           shapelib.SHPT_ARC: SHAPETYPE_ARC,
33                           shapelib.SHPT_POINT: SHAPETYPE_POINT}
34    
35    
36    class Shape:
37    
38        """Represent one shape"""
39    
40        def __init__(self, points):
41            self.points = points
42            #self.compute_bbox()
43            self.bbox = None
44    
45        def compute_bbox(self):
46            if self.bbox is not None:
47                return self.bbox
48    
49            xs = []
50            ys = []
51            for x, y in self.points:
52                xs.append(x)
53                ys.append(y)
54            self.llx = min(xs)
55            self.lly = min(ys)
56            self.urx = max(xs)
57            self.ury = max(ys)
58    
59            self.bbox = (self.llx, self.lly, self.urx, self.ury)
60    
61            return self.bbox
62    
63        def Points(self):
64            return self.points
65    
66    
67    
68  class ShapeTable(transientdb.AutoTransientTable):  class ShapeTable(transientdb.AutoTransientTable):
69    
# Line 61  class ShapefileStore: Line 104  class ShapefileStore:
104          self.dbftable = table.DBFTable(filename)          self.dbftable = table.DBFTable(filename)
105          self.table = ShapeTable(self, session.TransientDB(), self.dbftable)          self.table = ShapeTable(self, session.TransientDB(), self.dbftable)
106    
107            self.numshapes, shapetype, mins, maxs = self.shapefile.info()
108            if self.numshapes:
109                self.bbox = mins[:2] + maxs[:2]
110            else:
111                self.bbox = None
112            self.shapetype = shapelib_shapetypes[shapetype]
113    
114            # estimate a good depth for the quad tree. Each depth multiplies
115            # the number of nodes by four, therefore we basically take the
116            # base 4 logarithm of the number of shapes.
117            if self.numshapes < 4:
118                maxdepth = 1
119            else:
120                maxdepth = int(ceil(log(self.numshapes / 4.0) / log(4)))
121    
122            self.shapetree = shptree.SHPTree(self.shapefile.cobject(), 2,
123                                             maxdepth)
124    
125      def Table(self):      def Table(self):
126          """Return the table containing the attribute data"""          """Return the table containing the attribute data"""
127          return self.table          return self.table
# Line 77  class ShapefileStore: Line 138  class ShapefileStore:
138          """Return the filetype. This is always the string 'shapefile'"""          """Return the filetype. This is always the string 'shapefile'"""
139          return "shapefile"          return "shapefile"
140    
141        def ShapeType(self):
142            """Return the type of the shapes in the shapestore.
143    
144            This is either SHAPETYPE_POINT, SHAPETYPE_ARC or SHAPETYPE_POLYGON.
145            """
146            return self.shapetype
147    
148        def NumShapes(self):
149            """Return the number of shapes in the shape store"""
150            return self.numshapes
151    
152      def Dependencies(self):      def Dependencies(self):
153          """Return the empty tuple.          """Return the empty tuple.
154    
# Line 91  class ShapefileStore: Line 163  class ShapefileStore:
163          """          """
164          return None          return None
165    
166        def BoundingBox(self):
167            """Return the bounding box of the shapes in the shapestore.
168    
169            The coordinate system used is whatever was used in the shapefile.
170            If the shapefile is empty, return None.
171            """
172            return self.bbox
173    
174        def ShapesInRegion(self, box):
175            """Return the ids of the shapes that overlap the box.
176    
177            Box is a tuple (left, bottom, right, top) in the coordinate
178            system used used in the shapefile.
179            """
180            left, bottom, right, top = box
181            return self.shapetree.find_shapes((left, bottom), (right, top))
182    
183        def Shape(self, index):
184            """Return the shape with index index"""
185            shape = self.shapefile.read_object(index)
186    
187            if self.ShapeType() == SHAPETYPE_POINT:
188                points = shape.vertices()
189            else:
190                #for poly in shape.vertices():
191                poly = shape.vertices()[0]
192                points = []
193                for x, y in poly:
194                    points.append((x, y))
195    
196            return Shape(points)
197    
198    
199    
200  class DerivedShapeStore:  class DerivedShapeStore:
201    
# Line 131  class DerivedShapeStore: Line 236  class DerivedShapeStore:
236          """          """
237          return self.shapestore          return self.shapestore
238    
239        def Shape(self, index):
240            """Return the shape with index index"""
241            return self.shapestore.Shape(index)
242    
243  class SimpleStore:      def ShapesInRegion(self, bbox):
244            """Return the ids of the shapes that overlap the box.
245    
246      """Combine a shapefile and a table object"""          This method is simply delegated to the shapestore the
247            DerivedShapeStore was instantiated with.
248            """
249            return self.shapestore.ShapesInRegion(bbox)
250    
251      def __init__(self, shapefile, table):      def ShapeType(self):
252          warnings.warn("The SimpleStore is deprecated."          """Return the type of the shapes in the layer.
                       " Use DerivedShapeStore instead",  
                       DeprecationWarning, stacklevel = 2)  
         self.shapefile = shapefile  
         self.table = table  
         self.filename = None  
253    
254      def Table(self):          This method is simply delegated to the shapestore the
255          return self.table          DerivedShapeStore was instantiated with.
256            """
257            return self.shapestore.ShapeType()
258    
259      def Shapefile(self):      def NumShapes(self):
260          return self.shapefile          """Return the number of shapes in the shapestore."""
261            return self.shapestore.NumShapes()
262    
263        def BoundingBox(self):
264            """Return the bounding box of the shapes in the shapestore.
265    
266            This method is simply delegated to the shapestore the
267            DerivedShapeStore was instantiated with.
268            """
269            return self.shapestore.BoundingBox()
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