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- from django.contrib.gis.gdal.base import GDALBase
- from django.contrib.gis.gdal.prototypes import raster as capi
-
-
- class GDALRasterBase(GDALBase):
- """
- Attributes that exist on both GDALRaster and GDALBand.
- """
- @property
- def metadata(self):
- """
- Return the metadata for this raster or band. The return value is a
- nested dictionary, where the first-level key is the metadata domain and
- the second-level is the metadata item names and values for that domain.
- """
- if not capi.get_ds_metadata_domain_list:
- raise ValueError('GDAL ≥ 1.11 is required for using the metadata property.')
-
- # The initial metadata domain list contains the default domain.
- # The default is returned if domain name is None.
- domain_list = ['DEFAULT']
-
- # Get additional metadata domains from the raster.
- meta_list = capi.get_ds_metadata_domain_list(self._ptr)
- if meta_list:
- # The number of domains is unknown, so retrieve data until there
- # are no more values in the ctypes array.
- counter = 0
- domain = meta_list[counter]
- while domain:
- domain_list.append(domain.decode())
- counter += 1
- domain = meta_list[counter]
-
- # Free domain list array.
- capi.free_dsl(meta_list)
-
- # Retrieve metadata values for each domain.
- result = {}
- for domain in domain_list:
- # Get metadata for this domain.
- data = capi.get_ds_metadata(
- self._ptr,
- (None if domain == 'DEFAULT' else domain.encode()),
- )
- if not data:
- continue
- # The number of metadata items is unknown, so retrieve data until
- # there are no more values in the ctypes array.
- domain_meta = {}
- counter = 0
- item = data[counter]
- while item:
- key, val = item.decode().split('=')
- domain_meta[key] = val
- counter += 1
- item = data[counter]
- # The default domain values are returned if domain is None.
- result[domain or 'DEFAULT'] = domain_meta
- return result
-
- @metadata.setter
- def metadata(self, value):
- """
- Set the metadata. Update only the domains that are contained in the
- value dictionary.
- """
- # Loop through domains.
- for domain, metadata in value.items():
- # Set the domain to None for the default, otherwise encode.
- domain = None if domain == 'DEFAULT' else domain.encode()
- # Set each metadata entry separately.
- for meta_name, meta_value in metadata.items():
- capi.set_ds_metadata_item(
- self._ptr, meta_name.encode(),
- meta_value.encode() if meta_value else None,
- domain,
- )
|
