django1/django/contrib/gis/gdal/__init__.py

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"""
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: Object for accessing OGR Geometry functionality.
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).
"""
from django.contrib.gis.gdal.error import check_err, OGRException, OGRIndexError, SRSException # NOQA
from django.contrib.gis.gdal.geomtype import OGRGeomType # NOQA
__all__ = [
'check_err', 'OGRException', 'OGRIndexError', 'SRSException', 'OGRGeomType',
'HAS_GDAL',
]
# 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 # NOQA
from django.contrib.gis.gdal.datasource import DataSource # NOQA
from django.contrib.gis.gdal.libgdal import gdal_version, gdal_full_version, GDAL_VERSION # NOQA
from django.contrib.gis.gdal.srs import SpatialReference, CoordTransform # NOQA
from django.contrib.gis.gdal.geometries import OGRGeometry # NOQA
HAS_GDAL = True
__all__ += [
'Driver', 'DataSource', 'gdal_version', 'gdal_full_version',
'GDAL_VERSION', 'SpatialReference', 'CoordTransform', 'OGRGeometry',
]
except OGRException:
HAS_GDAL = False
try:
from django.contrib.gis.gdal.envelope import Envelope
__all__ += ['Envelope']
except ImportError:
# No ctypes, but don't raise an exception.
pass