import os import re from ctypes import c_char_p, CDLL from ctypes.util import find_library from django.contrib.gis.gdal.error import OGRException # Custom library path set? try: from django.conf import settings lib_path = settings.GDAL_LIBRARY_PATH except (AttributeError, EnvironmentError, ImportError): lib_path = None if lib_path: lib_names = None elif os.name == 'nt': # Windows NT shared libraries lib_names = ['gdal18', 'gdal17', 'gdal16', 'gdal15'] elif os.name == 'posix': # *NIX library names. lib_names = ['gdal', 'GDAL', 'gdal1.8.0', 'gdal1.7.0', 'gdal1.6.0', 'gdal1.5.0', 'gdal1.4.0'] else: raise OGRException('Unsupported OS "%s"' % os.name) # Using the ctypes `find_library` utility to find the # path to the GDAL library from the list of library names. if lib_names: for lib_name in lib_names: lib_path = find_library(lib_name) if not lib_path is None: break if lib_path is None: raise OGRException('Could not find the GDAL library (tried "%s"). ' 'Try setting GDAL_LIBRARY_PATH in your settings.' % '", "'.join(lib_names)) # This loads the GDAL/OGR C library lgdal = CDLL(lib_path) # On Windows, the GDAL binaries have some OSR routines exported with # STDCALL, while others are not. Thus, the library will also need to # be loaded up as WinDLL for said OSR functions that require the # different calling convention. if os.name == 'nt': from ctypes import WinDLL lwingdal = WinDLL(lib_path) def std_call(func): """ Returns the correct STDCALL function for certain OSR routines on Win32 platforms. """ if os.name == 'nt': return lwingdal[func] else: return lgdal[func] #### Version-information functions. #### # Returns GDAL library version information with the given key. _version_info = std_call('GDALVersionInfo') _version_info.argtypes = [c_char_p] _version_info.restype = c_char_p def gdal_version(): "Returns only the GDAL version number information." return _version_info('RELEASE_NAME') def gdal_full_version(): "Returns the full GDAL version information." return _version_info('') def gdal_release_date(date=False): """ Returns the release date in a string format, e.g, "2007/06/27". If the date keyword argument is set to True, a Python datetime object will be returned instead. """ from datetime import date as date_type rel = _version_info('RELEASE_DATE') yy, mm, dd = map(int, (rel[0:4], rel[4:6], rel[6:8])) d = date_type(yy, mm, dd) if date: return d else: return d.strftime('%Y/%m/%d') version_regex = re.compile(r'^(?P\d+)\.(?P\d+)(\.(?P\d+))?') def gdal_version_info(): ver = gdal_version() m = version_regex.match(ver) if not m: raise OGRException('Could not parse GDAL version string "%s"' % ver) return dict([(key, m.group(key)) for key in ('major', 'minor', 'subminor')]) _verinfo = gdal_version_info() GDAL_MAJOR_VERSION = int(_verinfo['major']) GDAL_MINOR_VERSION = int(_verinfo['minor']) GDAL_SUBMINOR_VERSION = _verinfo['subminor'] and int(_verinfo['subminor']) GDAL_VERSION = (GDAL_MAJOR_VERSION, GDAL_MINOR_VERSION, GDAL_SUBMINOR_VERSION) del _verinfo # GeoJSON support is available only in GDAL 1.5+. if GDAL_VERSION >= (1, 5): GEOJSON = True else: GEOJSON = False