/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/postgisdb.py
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revision 1656 by bh, Mon Aug 25 18:26:54 2003 UTC revision 1660 by bh, Tue Aug 26 12:54:45 2003 UTC
# Line 180  class PostGISTable: Line 180  class PostGISTable:
180          """Return the name of the table in the database"""          """Return the name of the table in the database"""
181          return self.tablename          return self.tablename
182    
183        def Title(self):
184            """Return the title of the table.
185    
186            The title is currently fixed and equal to the tablename
187            """
188            return self.tablename
189    
190      def Dependencies(self):      def Dependencies(self):
191          """Return an empty tuple because a PostGISTable depends on nothing else          """Return an empty tuple because a PostGISTable depends on nothing else
192          """          """
# Line 333  class PostGISShapeStore(PostGISTable): Line 340  class PostGISShapeStore(PostGISTable):
340          y=[]          y=[]
341          cursor = self.db.cursor()          cursor = self.db.cursor()
342          try:          try:
343              stmt = ("SELECT AsText(Envelope(%s)) FROM %s;"              # Using the extent function is postgis specific. An OGC
344                      % (self.geometry_column, self.tablename))              # Simple Features compliant solution would be to use a query
345              cursor.execute(stmt)              # like "SELECT AsText(Envelope(the_geom)) FROM mytable;" and
346                # calculate the bounding box by hand from that
347                cursor.execute("SELECT extent(%s) FROM %s;"
348                               % (self.geometry_column, self.tablename))
349              result = cursor.fetchone()              result = cursor.fetchone()
350              while result:              if result:
351                  result = result[0]                  (minx, miny), (maxx, maxy) \
352                  # Here we must do some parsing through the result string                        = wellknowntext.parse_wkt_thuban(result[0])[0]
353                  # to get the points out of the polygon which representes                  return (minx, miny, maxx, maxy)
                 # the bounding box The first and the last point of a  
                 # polygon are identical  
                 result = result.split("(")[2]  
                 result = result.split(")")[0]  
                 points = result.split(",")  
                 del points[4] # Remove the last point  
                 for point in points:  
                     px, py = point.split()  
                     x.append(float(px))  
                     y.append(float(py))  
                 result = cursor.fetchone()  
354          finally:          finally:
355              cursor.close()              cursor.close()
         if not x:  
             # Empty table  
             return None  
         return (min(x), min(y), max(x), max(y))  
356    
357      def Shape(self, shapeid):      def Shape(self, shapeid):
358          cursor = self.db.cursor()          cursor = self.db.cursor()
# Line 367  class PostGISShapeStore(PostGISTable): Line 362  class PostGISShapeStore(PostGISTable):
362          cursor.close()          cursor.close()
363          return PostGISShape(shapeid, wkt)          return PostGISShape(shapeid, wkt)
364    
365        def AllShapes(self):
366            cursor = self.db.cursor()
367            cursor.execute("SELECT gid, AsText(%s) FROM %s ORDER BY gid"
368                           % (self.geometry_column, self.tablename))
369            while 1:
370                result = cursor.fetchone()
371                if result is None:
372                    return
373                yield PostGISShape(result[0], result[1])
374    
375    
376      def ShapesInRegion(self, bbox):      def ShapesInRegion(self, bbox):
377          """Generate all shapes overlapping the region given by bbox."""          """Generate all shapes overlapping the region given by bbox."""
378          # IMPORTANT:This will work for PostGIS < 0.8          # IMPORTANT:This will work for PostGIS < 0.8
# Line 382  class PostGISShapeStore(PostGISTable): Line 388  class PostGISShapeStore(PostGISTable):
388          while 1:          while 1:
389              result = cursor.fetchone()              result = cursor.fetchone()
390              if result is None:              if result is None:
391                  raise StopIteration                  return
392              yield PostGISShape(result[0], result[1])              yield PostGISShape(result[0], result[1])
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