/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/data.py

Diff of /branches/WIP-pyshapelib-bramz/Thuban/Model/data.py

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-revision 1593 by bh,
Fri Aug 15 14:10:27 2003 UTC
+revision 2605 by jan,
Wed Apr 27 11:04:56 2005 UTC
 Line 1
- # Copyright (C) 2003 by Intevation GmbH
+ # Copyright (C) 2003, 2005 by Intevation GmbH
  # Authors:
  # Bernhard Herzog <[email protected]>
  #
 Line 45 
 RAW_PYTHON = "RAW_PYTHON"
  # raw data.
  RAW_SHAPEFILE = "RAW_SHAPEFILE"
+ # Raw data in well-known text format
+ RAW_WKT = "RAW_WKT"
  class ShapefileShape:
-Line 109 
 class ShapeTable(transientdb.AutoTransie
+Line 112 
 class ShapeTable(transientdb.AutoTransie
          """Return a tuple containing the shapestore"""
          return (self.store(),)
+ # XXX: (this statement should be kept in mind when re-engeneering)
+ #
+ # From a desing POV it was wrong to distinguish between table and
+ # shapestore.  In hindsight the only reason for doing so was that the
+ # shapelib has different objects for the shapefile(s) and the dbf file,
+ # which of course matches the way the data is organized into different
+ # files.  So the distinction between shapestore and table is an artifact
+ # of the shapefile format.  When we added the postgis support we should
+ # have adopted the table interface for the entire shape store, making the
+ # geometry data an additional column for those shape stores that don't
+ # store the geometries in columns in the first place.
+ class FileShapeStore:
+     """The base class to derive any file-based ShapeStore from.
+     This class contains all information that is needed by a
+     loader routine to actually load the shapestore.
+     This essentially means that the class contains all required information
+     to save the shapestore specification (i.e. in a .thuban file).
+     """
+     def __init__(self, filename, sublayer_name = None):
+         """Initialize the base class with main parameters.
+         filename  -- the source filename.
+                      This filename will be converted to an absolute filename.
+                      The filename will be interpreted relative to the .thuban file anyway,
+                      but when saving a session we need to compare absolute paths
+                      and it's usually safer to always work with absolute paths.
+         sublayer_name -- a string representing a layer within the file shape store.
+                      Some file formats support to contain several layers, or
+                      at least the ogr library says so.
+                      For those filetypes who don't, the sublayer_name can be ignored
+                      and by default it is None.
+         """
+         self._filename = os.path.abspath(filename)
+         self._sublayer_name = sublayer_name
+     def FileName(self):
+         """Return the filename used to open the shapestore.
+         The filename can only be set via __init__ method.
+         """
+         return self._filename
+     def FileType(self):
+         """Return the filetype.
+         The filetype has to be set in all derived classes.
+         It must be string.
+         Known and used types are: "shapefile"
+         """
+         raise NotImplementedError
+     def SublayerName(self):
+         """Return the sublayer_name.
+         This could be None if the shapestore type only supports a single
+         layer.
+         """
+         return self._sublayer_name
+     # Design/Implementation note:
+     # It is not a good idea to have a implementation for a
+     # "setBoundingBox" or BoundingBox in this base class.
+     # In future this data might change during
+     # a Thuban session and thus can not be kept statically here.
+     # It is expected that for many derived classes the bbox must
+     # be retrieved each time anew.
+     def BoundingBox(self):
+         """Return the bounding box of the shapes in the shape store.
+         The coordinate system used is whatever was used in the shape store.
+         If the shape store is empty, return None.
+         """
+         raise NotImplementedError
- class ShapefileStore:
+ class ShapefileStore(FileShapeStore):
      """Combine a shapefile and the corresponding DBF file into one object"""
      def __init__(self, session, filename):
-         # Make the filename absolute. The filename will be
+         FileShapeStore.__init__(self, filename)
-         # interpreted relative to that anyway, but when saving a
-         # session we need to compare absolute paths and it's usually
-         # safer to always work with absolute paths.
-         self.filename = os.path.abspath(filename)
-         self.shapefile = shapelib.ShapeFile(self.filename)
          self.dbftable = table.DBFTable(filename)
-         self.table = ShapeTable(self, session.TransientDB(), self.dbftable)
+         self._table = ShapeTable(self, session.TransientDB(), self.dbftable)
+         self._bbox = None
+         self._open_shapefile()
+     def _open_shapefile(self):
+         self.shapefile = shapelib.ShapeFile(self.FileName())
          self.numshapes, shapetype, mins, maxs = self.shapefile.info()
          if self.numshapes:
-             self.bbox = mins[:2] + maxs[:2]
+             self._bbox = mins[:2] + maxs[:2]
          else:
-             self.bbox = None
+             self._bbox = None
          self.shapetype = shapelib_shapetypes[shapetype]
          # estimate a good depth for the quad tree. Each depth multiplies
-Line 144 
 class ShapefileStore:
+Line 224 
 class ShapefileStore:
                                           maxdepth)
      def Table(self):
-         """Return the table containing the attribute data"""
+         """Return the table containing the attribute data."""
-         return self.table
+         return self._table
      def Shapefile(self):
          """Return the shapefile object"""
          return self.shapefile
-     def FileName(self):
-         """Return the filename used to open the shapefile"""
-         return self.filename
      def FileType(self):
          """Return the filetype. This is always the string 'shapefile'"""
          return "shapefile"
-Line 171 
 class ShapefileStore:
+Line 247 
 class ShapefileStore:
          return RAW_SHAPEFILE
      def NumShapes(self):
-         """Return the number of shapes in the shape store"""
+         """Return the number of shapes in the shapefile"""
          return self.numshapes
      def Dependencies(self):
-Line 189 
 class ShapefileStore:
+Line 265 
 class ShapefileStore:
          return None
      def BoundingBox(self):
-         """Return the bounding box of the shapes in the shapestore.
+         """Return the bounding box of the shapes in the shapefile.
          The coordinate system used is whatever was used in the shapefile.
-         If the shapefile is empty, return None.
+         If the shapefileis empty, return None.
          """
-         return self.bbox
+         return self._bbox
      def ShapesInRegion(self, bbox):
          """Return an iterable over the shapes that overlap the bounding box.
          The bbox parameter should be the bounding box as a tuple in the
          form (minx, miny, maxx, maxy) in the coordinate system of the
-         shape store.
+         shapefile.
          """
+         # Bind a few globals to locals to make it a bit faster
+         cls = ShapefileShape
+         shapefile = self.shapefile
          left, bottom, right, top = bbox
          for i in self.shapetree.find_shapes((left, bottom), (right, top)):
-             yield ShapefileShape(self.shapefile, i)
+             yield cls(shapefile, i)
      def AllShapes(self):
-         """Return an iterable over the shapes in the shape store."""
+         """Return an iterable over the shapes in the shapefile."""
          for i in xrange(self.NumShapes()):
              yield ShapefileShape(self.shapefile, i)
-Line 217 
 class ShapefileStore:
+Line 297 
 class ShapefileStore:
          return ShapefileShape(self.shapefile, index)
  class DerivedShapeStore:
      """A ShapeStore derived from other shapestores or tables"""
-Line 270 
 class DerivedShapeStore:
+Line 349 
 class DerivedShapeStore:
          return self.shapestore.ShapesInRegion(bbox)
      def AllShapes(self):
-         """Return an iterable over the shapes in the shape store.
+         """Return an iterable over the shapes in the shapefile.
          This method is simply delegated to the shapestore the
          DerivedShapeStore was instantiated with.

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