/[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 1921 by bh, Mon Nov 3 18:42:27 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 _  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 61  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 77  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 91  class ShapefileStore: Line 191  class ShapefileStore:
191          """          """
192          return None          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            # Bind a few globals to locals to make it a bit faster
210            cls = ShapefileShape
211            shapefile = self.shapefile
212    
213            left, bottom, right, top = bbox
214            for i in self.shapetree.find_shapes((left, bottom), (right, top)):
215                yield cls(shapefile, i)
216    
217        def AllShapes(self):
218            """Return an iterable over the shapes in the shape store."""
219            for i in xrange(self.NumShapes()):
220                yield ShapefileShape(self.shapefile, i)
221    
222        def Shape(self, index):
223            """Return the shape with index index"""
224            return ShapefileShape(self.shapefile, index)
225    
226    
227    
228  class DerivedShapeStore:  class DerivedShapeStore:
229    
# Line 131  class DerivedShapeStore: Line 264  class DerivedShapeStore:
264          """          """
265          return self.shapestore          return self.shapestore
266    
267        def Shape(self, index):
268            """Return the shape with index index"""
269            return self.shapestore.Shape(index)
270    
271  class SimpleStore:      def ShapesInRegion(self, bbox):
272            """Return the ids of the shapes that overlap the box.
273    
274      """Combine a shapefile and a table object"""          This method is simply delegated to the shapestore the
275            DerivedShapeStore was instantiated with.
276            """
277            return self.shapestore.ShapesInRegion(bbox)
278    
279      def __init__(self, shapefile, table):      def AllShapes(self):
280          warnings.warn("The SimpleStore is deprecated."          """Return an iterable over the shapes in the shape store.
                       " Use DerivedShapeStore instead",  
                       DeprecationWarning, stacklevel = 2)  
         self.shapefile = shapefile  
         self.table = table  
         self.filename = None  
281    
282      def Table(self):          This method is simply delegated to the shapestore the
283          return self.table          DerivedShapeStore was instantiated with.
284            """
285            return self.shapestore.AllShapes()
286    
287      def Shapefile(self):      def ShapeType(self):
288          return self.shapefile          """Return the type of the shapes in the layer.
289    
290            This method is simply delegated to the shapestore the
291            DerivedShapeStore was instantiated with.
292            """
293            return self.shapestore.ShapeType()
294    
295        def RawShapeFormat(self):
296            """Return the raw data format of the shapes.
297    
298            This method is simply delegated to the shapestore the
299            DerivedShapeStore was instantiated with.
300            """
301            return self.shapestore.RawShapeFormat()
302    
303        def NumShapes(self):
304            """Return the number of shapes in the shapestore."""
305            return self.shapestore.NumShapes()
306    
307        def BoundingBox(self):
308            """Return the bounding box of the shapes in the shapestore.
309    
310            This method is simply delegated to the shapestore the
311            DerivedShapeStore was instantiated with.
312            """
313            return self.shapestore.BoundingBox()
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