65 lines
2.1 KiB
Python
65 lines
2.1 KiB
Python
from django.db.models.aggregates import Aggregate
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from django.contrib.gis.db.models.fields import ExtentField
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__all__ = ['Collect', 'Extent', 'Extent3D', 'MakeLine', 'Union']
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class GeoAggregate(Aggregate):
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function = None
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is_extent = False
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def as_sql(self, compiler, connection):
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self.function = connection.ops.spatial_aggregate_name(self.name)
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return super(GeoAggregate, self).as_sql(compiler, connection)
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def as_oracle(self, compiler, connection):
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if not hasattr(self, 'tolerance'):
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self.tolerance = 0.05
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self.extra['tolerance'] = self.tolerance
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if not self.is_extent:
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self.template = '%(function)s(SDOAGGRTYPE(%(expressions)s,%(tolerance)s))'
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return self.as_sql(compiler, connection)
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def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
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c = super(GeoAggregate, self).resolve_expression(query, allow_joins, reuse, summarize, for_save)
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if not hasattr(c.input_field.field, 'geom_type'):
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raise ValueError('Geospatial aggregates only allowed on geometry fields.')
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return c
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def convert_value(self, value, connection, context):
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return connection.ops.convert_geom(value, self.output_field)
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class Collect(GeoAggregate):
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name = 'Collect'
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class Extent(GeoAggregate):
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name = 'Extent'
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is_extent = '2D'
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def __init__(self, expression, **extra):
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super(Extent, self).__init__(expression, output_field=ExtentField(), **extra)
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def convert_value(self, value, connection, context):
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return connection.ops.convert_extent(value, context.get('transformed_srid'))
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class Extent3D(GeoAggregate):
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name = 'Extent3D'
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is_extent = '3D'
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def __init__(self, expression, **extra):
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super(Extent3D, self).__init__(expression, output_field=ExtentField(), **extra)
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def convert_value(self, value, connection, context):
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return connection.ops.convert_extent3d(value, context.get('transformed_srid'))
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class MakeLine(GeoAggregate):
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name = 'MakeLine'
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class Union(GeoAggregate):
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name = 'Union'
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