+
−"""
+
− This module houses ctypes interfaces for GDAL objects.  The following GDAL
+
− objects are supported:
+
−
+
− CoordTransform: Used for coordinate transformations from one spatial
+
−  reference system to another.
+
−
+
− Driver: Wraps an OGR data source driver.
+
−  
+
− DataSource: Wrapper for the OGR data source object, supports
+
−  OGR-supported data sources.
+
−
+
− Envelope: A ctypes structure for bounding boxes (GDAL library
+
−  not required).
+
−
+
− OGRGeometry: Layer for accessing OGR Geometry objects.
+
−
+
− OGRGeomType: A class for representing the different OGR Geometry
+
−  types (GDAL library not required).
+
−
+
− SpatialReference: Represents OSR Spatial Reference objects.
+
−
+
− The GDAL library will be imported from the system path using the default  
+
− library name for the current OS. The default library path may be overridden
+
− by setting `GDAL_LIBRARY_PATH` in your settings with the path to the GDAL C 
+
− library on your system.  
+
−
+
− GDAL links to a large number of external libraries that consume RAM when 
+
− loaded.  Thus, it may desirable to disable GDAL on systems with limited
+
− RAM resources -- this may be accomplished by setting `GDAL_LIBRARY_PATH`
+
− to a non-existant file location (e.g., `GDAL_LIBRARY_PATH='/null/path'`; 
+
− setting to None/False/'' will not work as a string must be given).
+
−"""
+
−import sys
+
−
+
−# Attempting to import objects that depend on the GDAL library.  The
+
−# HAS_GDAL flag will be set to True if the library is present on
+
−# the system.
+
−try:
+
−    from django.contrib.gis.gdal.driver import Driver
+
−    from django.contrib.gis.gdal.datasource import DataSource
+
−    from django.contrib.gis.gdal.libgdal import gdal_version, gdal_full_version, gdal_release_date
+
−    from django.contrib.gis.gdal.srs import SpatialReference, CoordTransform
+
−    from django.contrib.gis.gdal.geometries import OGRGeometry, GEOJSON
+
−    HAS_GDAL = True
+
−except:
+
−    HAS_GDAL, GEOJSON = False, False
+
−
+
−# The envelope, error, and geomtype modules do not actually require the
+
−# GDAL library, but still nead at least Python 2.4 and ctypes.
+
−PYTHON23 = sys.version_info[0] == 2 and sys.version_info[1] == 3
+
−if not PYTHON23:
+
−    try:
+
−        from django.contrib.gis.gdal.envelope import Envelope
+
−        from django.contrib.gis.gdal.error import check_err, OGRException, OGRIndexError, SRSException
+
−        from django.contrib.gis.gdal.geomtype import OGRGeomType
+
−    except ImportError:
+
−        # No ctypes, but don't raise an exception.
+
−        pass