/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/data.py
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revision 984 by bh, Thu May 22 16:37:48 2003 UTC revision 1605 by bh, Tue Aug 19 11:00:40 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  # $Id$  # $Id$
15    
16  import os  import os
 import warnings  
17  import weakref  import weakref
18    from math import ceil, log
19    
20  import shapelib  import shapelib
21    import shptree
22  import table  import table
23  import transientdb  import transientdb
24    
25    from Thuban import _
26    
27    # Shape type constants
28    SHAPETYPE_POLYGON = "polygon"
29    SHAPETYPE_ARC = "arc"
30    SHAPETYPE_POINT = "point"
31    
32    # mapping from shapelib shapetype constants to our constants
33    shapelib_shapetypes = {shapelib.SHPT_POLYGON: SHAPETYPE_POLYGON,
34                           shapelib.SHPT_ARC: SHAPETYPE_ARC,
35                           shapelib.SHPT_POINT: SHAPETYPE_POINT}
36    
37    #
38    # Raw shape data formats
39    #
40    
41    # Raw data is the same as that returned by the points method.
42    RAW_PYTHON = "RAW_PYTHON"
43    
44    # Raw data is a shapefile. The Shape object will use the shapeid as the
45    # raw data.
46    RAW_SHAPEFILE = "RAW_SHAPEFILE"
47    
48    # Raw data in well-known text format
49    RAW_WKT = "RAW_WKT"
50    
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 = []
65            ys = []
66            for part in self.Points():
67                for x, y in part:
68                    xs.append(x)
69                    ys.append(y)
70            return (min(xs), min(ys), max(xs), max(ys))
71    
72        def ShapeID(self):
73            return self.shapeid
74    
75        def Points(self):
76            """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):
93    
# Line 59  class ShapefileStore: Line 128  class ShapefileStore:
128          self.dbftable = table.DBFTable(filename)          self.dbftable = table.DBFTable(filename)
129          self.table = ShapeTable(self, session.TransientDB(), self.dbftable)          self.table = ShapeTable(self, session.TransientDB(), self.dbftable)
130    
131            self.numshapes, shapetype, mins, maxs = self.shapefile.info()
132            if self.numshapes:
133                self.bbox = mins[:2] + maxs[:2]
134            else:
135                self.bbox = None
136            self.shapetype = shapelib_shapetypes[shapetype]
137    
138            # estimate a good depth for the quad tree. Each depth multiplies
139            # the number of nodes by four, therefore we basically take the
140            # base 4 logarithm of the number of shapes.
141            if self.numshapes < 4:
142                maxdepth = 1
143            else:
144                maxdepth = int(ceil(log(self.numshapes / 4.0) / log(4)))
145    
146            self.shapetree = shptree.SHPTree(self.shapefile.cobject(), 2,
147                                             maxdepth)
148    
149      def Table(self):      def Table(self):
150          """Return the table containing the attribute data"""          """Return the table containing the attribute data"""
151          return self.table          return self.table
# Line 75  class ShapefileStore: Line 162  class ShapefileStore:
162          """Return the filetype. This is always the string 'shapefile'"""          """Return the filetype. This is always the string 'shapefile'"""
163          return "shapefile"          return "shapefile"
164    
165        def ShapeType(self):
166            """Return the type of the shapes in the shapestore.
167    
168            This is either SHAPETYPE_POINT, SHAPETYPE_ARC or SHAPETYPE_POLYGON.
169            """
170            return self.shapetype
171    
172        def RawShapeFormat(self):
173            """Return the raw data format of the shape data, i.e. RAW_SHAPEFILE"""
174            return RAW_SHAPEFILE
175    
176        def NumShapes(self):
177            """Return the number of shapes in the shape store"""
178            return self.numshapes
179    
180      def Dependencies(self):      def Dependencies(self):
181          """Return the empty tuple.          """Return the empty tuple.
182    
# Line 82  class ShapefileStore: Line 184  class ShapefileStore:
184          """          """
185          return ()          return ()
186    
187        def OrigShapeStore(self):
188            """Return None.
189    
190            The ShapefileStore was not derived from another shapestore.
191            """
192            return None
193    
194        def BoundingBox(self):
195            """Return the bounding box of the shapes in the shapestore.
196    
197            The coordinate system used is whatever was used in the shapefile.
198            If the shapefile is empty, return None.
199            """
200            return self.bbox
201    
202        def ShapesInRegion(self, bbox):
203            """Return an iterable over the shapes that overlap the bounding box.
204    
205            The bbox parameter should be the bounding box as a tuple in the
206            form (minx, miny, maxx, maxy) in the coordinate system of the
207            shape store.
208            """
209            left, bottom, right, top = bbox
210            for i in self.shapetree.find_shapes((left, bottom), (right, top)):
211                yield ShapefileShape(self.shapefile, i)
212    
213        def AllShapes(self):
214            """Return an iterable over the shapes in the shape store."""
215            for i in xrange(self.NumShapes()):
216                yield ShapefileShape(self.shapefile, i)
217    
218        def Shape(self, index):
219            """Return the shape with index index"""
220            return ShapefileShape(self.shapefile, index)
221    
222    
223    
224  class DerivedShapeStore:  class DerivedShapeStore:
225    
# Line 92  class DerivedShapeStore: Line 230  class DerivedShapeStore:
230    
231          The arguments are a shapestore for the shapedata and a table for          The arguments are a shapestore for the shapedata and a table for
232          the tabular data.          the tabular data.
233    
234            Raises ValueError if the number of shapes in the shapestore
235            is different from the number of rows in the table.
236          """          """
237    
238            numShapes = shapestore.Shapefile().info()[0]
239            if numShapes != table.NumRows():
240                raise ValueError(_("Table not compatible with shapestore."))
241    
242          self.shapestore = shapestore          self.shapestore = shapestore
243          self.table = table          self.table = table
244    
# Line 101  class DerivedShapeStore: Line 247  class DerivedShapeStore:
247          return self.table          return self.table
248    
249      def Shapefile(self):      def Shapefile(self):
250          """Return the shapefile of he underlying shapestore"""          """Return the shapefile of the underlying shapestore"""
251          return self.shapestore.Shapefile()          return self.shapestore.Shapefile()
252    
253      def Dependencies(self):      def Dependencies(self):
254          """Return a tuple containing the shapestore and the table"""          """Return a tuple containing the shapestore and the table"""
255          return (self.shapestore, self.table)          return (self.shapestore, self.table)
256    
257        def OrigShapeStore(self):
258            """
259            Return the original shapestore the derived store was instantiated with
260            """
261            return self.shapestore
262    
263  class SimpleStore:      def Shape(self, index):
264            """Return the shape with index index"""
265            return self.shapestore.Shape(index)
266    
267      """Combine a shapefile and a table object"""      def ShapesInRegion(self, bbox):
268            """Return the ids of the shapes that overlap the box.
269    
270      def __init__(self, shapefile, table):          This method is simply delegated to the shapestore the
271          warnings.warn("The SimpleStore is deprecated."          DerivedShapeStore was instantiated with.
272                        " Use DerivedShapeStore instead",          """
273                        DeprecationWarning, stacklevel = 2)          return self.shapestore.ShapesInRegion(bbox)
         self.shapefile = shapefile  
         self.table = table  
         self.filename = None  
274    
275      def Table(self):      def AllShapes(self):
276          return self.table          """Return an iterable over the shapes in the shape store.
277    
278      def Shapefile(self):          This method is simply delegated to the shapestore the
279          return self.shapefile          DerivedShapeStore was instantiated with.
280            """
281            return self.shapestore.AllShapes()
282    
283        def ShapeType(self):
284            """Return the type of the shapes in the layer.
285    
286            This method is simply delegated to the shapestore the
287            DerivedShapeStore was instantiated with.
288            """
289            return self.shapestore.ShapeType()
290    
291        def RawShapeFormat(self):
292            """Return the raw data format of the shapes.
293    
294            This method is simply delegated to the shapestore the
295            DerivedShapeStore was instantiated with.
296            """
297            return self.shapestore.RawShapeFormat()
298    
299        def NumShapes(self):
300            """Return the number of shapes in the shapestore."""
301            return self.shapestore.NumShapes()
302    
303        def BoundingBox(self):
304            """Return the bounding box of the shapes in the shapestore.
305    
306            This method is simply delegated to the shapestore the
307            DerivedShapeStore was instantiated with.
308            """
309            return self.shapestore.BoundingBox()
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