66 lines
2.4 KiB
Python
66 lines
2.4 KiB
Python
# prerequisites imports
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from ctypes import c_void_p
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from django.contrib.gis.gdal.base import GDALBase
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from django.contrib.gis.gdal.error import OGRException
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from django.contrib.gis.gdal.prototypes import ds as capi
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# For more information, see the OGR C API source code:
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# http://www.gdal.org/ogr/ogr__api_8h.html
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#
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# The OGR_Dr_* routines are relevant here.
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class Driver(GDALBase):
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"Wraps an OGR Data Source Driver."
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# Case-insensitive aliases for OGR Drivers.
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_alias = {'esri' : 'ESRI Shapefile',
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'shp' : 'ESRI Shapefile',
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'shape' : 'ESRI Shapefile',
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'tiger' : 'TIGER',
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'tiger/line' : 'TIGER',
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}
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def __init__(self, dr_input):
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"Initializes an OGR driver on either a string or integer input."
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if isinstance(dr_input, basestring):
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# If a string name of the driver was passed in
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self._register()
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# Checking the alias dictionary (case-insensitive) to see if an alias
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# exists for the given driver.
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if dr_input.lower() in self._alias:
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name = self._alias[dr_input.lower()]
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else:
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name = dr_input
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# Attempting to get the OGR driver by the string name.
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dr = capi.get_driver_by_name(name)
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elif isinstance(dr_input, int):
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self._register()
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dr = capi.get_driver(dr_input)
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elif isinstance(dr_input, c_void_p):
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dr = dr_input
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else:
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raise OGRException('Unrecognized input type for OGR Driver: %s' % str(type(dr_input)))
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# Making sure we get a valid pointer to the OGR Driver
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if not dr:
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raise OGRException('Could not initialize OGR Driver on input: %s' % str(dr_input))
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self.ptr = dr
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def __str__(self):
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"Returns the string name of the OGR Driver."
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return capi.get_driver_name(self.ptr)
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def _register(self):
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"Attempts to register all the data source drivers."
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# Only register all if the driver count is 0 (or else all drivers
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# will be registered over and over again)
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if not self.driver_count: capi.register_all()
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# Driver properties
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@property
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def driver_count(self):
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"Returns the number of OGR data source drivers registered."
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return capi.get_driver_count()
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