def _create_export_datasource(
self,
tmp_folder,
layer_name,
export_format,
export_projection,
layer_geom_type):
GDAL_Driver = self._get_GDAL_Driver_by_export_format(export_format)
driver = ogr.GetDriverByName(GDAL_Driver)
# Create the data source
abs_filepath = os.path.join(
tmp_folder,
layer_name) + "." + export_format
datasource_options = self._get_datasource_options(GDAL_Driver)
data_source = driver.CreateDataSource(
abs_filepath,
options=datasource_options)
# Create the spatial reference
srs = osr.SpatialReference()
srs.ImportFromEPSG(export_projection)
# Create the layer
layer_options = self._get_layer_options(GDAL_Driver)
layer = data_source.CreateLayer(
str(layer_name),
srs,
layer_geom_type,
options=layer_options)
return data_source, layer
def _get_SRS(self, layer):
default_epsg = 4326
if layer.GetSpatialRef():
prj = layer.GetSpatialRef().ExportToWkt()
srs_osr = osr.SpatialReference()
srs_osr.ImportFromESRI([prj])
epsg = srs_osr.GetAuthorityCode(None)
if epsg is None or epsg == 0:
epsg = default_epsg
return int(epsg)
else:
return default_epsg
def _init_export(self, resource_id, export_format, export_projection):
postgis_layer, connection = self._get_layer(resource_id)
if postgis_layer is None:
return None
# Set up the export GDAL driver
tmp_folder = self._create_temp_export_folder()
resource_name = self._get_resource_name(resource_id)
if DBTableResource.name_suffix in resource_name:
resource_name = resource_name.replace(DBTableResource.name_suffix, '')
export_datasource, export_layer = self._create_export_datasource(
tmp_folder, resource_name, export_format, export_projection,
postgis_layer.GetGeomType())
postgis_srs = self._get_SRS(postgis_layer)
coordTrans = None
if not export_projection == postgis_srs:
# input SpatialReference
inSpatialRef = osr.SpatialReference()
inSpatialRef.ImportFromEPSG(postgis_srs)
# output SpatialReference
outSpatialRef = osr.SpatialReference()
outSpatialRef.ImportFromEPSG(export_projection)
# create the CoordinateTransformation
coordTrans = osr.CoordinateTransformation(
inSpatialRef,
outSpatialRef)
postgislyrDefn = postgis_layer.GetLayerDefn()
for i in range(postgislyrDefn.GetFieldCount()):
fieldName = postgislyrDefn.GetFieldDefn(i).GetName()
fieldTypeCode = postgislyrDefn.GetFieldDefn(i).GetType()
fieldType = postgislyrDefn.GetFieldDefn(
i).GetFieldTypeName(fieldTypeCode)
fieldWidth = postgislyrDefn.GetFieldDefn(i).GetWidth()
fieldPrecision = postgislyrDefn.GetFieldDefn(i).GetPrecision()
field_region = ogr.FieldDefn(fieldName, fieldTypeCode)
field_region.SetWidth(fieldWidth)
field_region.SetPrecision(fieldPrecision)
export_layer.CreateField(field_region)
field_region.Destroy()
for feat in postgis_layer:
# create the feature
feature = ogr.Feature(export_layer.GetLayerDefn())
# Set the attributes using the values from the delimited text file
for i in range(postgislyrDefn.GetFieldCount()):
fieldName = postgislyrDefn.GetFieldDefn(i).GetName()
feature.SetField(fieldName, feat[fieldName])
geom = feat.GetGeometryRef()
if coordTrans:
geom.Transform(coordTrans)
try:
feature.SetGeometry(geom)
except RuntimeError:
pass
export_layer.CreateFeature(feature)
feature.Destroy()
export_datasource.Destroy()
file_path = self._create_zip(tmp_folder)
connection.Destroy()
shutil.rmtree(tmp_folder)
resp = self._send_file_response(file_path, resource_name)
#os.remove(file_path) Needs Fix to delete files
return resp