86 lines
3.0 KiB
Python
86 lines
3.0 KiB
Python
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"""
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Geometry factories based on the geo interface
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"""
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from .point import Point, asPoint
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from .linestring import LineString, asLineString
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from .polygon import Polygon, asPolygon
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from .multipoint import MultiPoint, asMultiPoint
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from .multilinestring import MultiLineString, asMultiLineString
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from .multipolygon import MultiPolygon, MultiPolygonAdapter
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from .collection import GeometryCollection
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def box(minx, miny, maxx, maxy, ccw=True):
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"""Returns a rectangular polygon with configurable normal vector"""
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coords = [(maxx, miny), (maxx, maxy), (minx, maxy), (minx, miny)]
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if not ccw:
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coords = coords[::-1]
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return Polygon(coords)
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def shape(context):
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"""Returns a new, independent geometry with coordinates *copied* from the
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context.
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"""
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if hasattr(context, "__geo_interface__"):
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ob = context.__geo_interface__
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else:
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ob = context
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geom_type = ob.get("type").lower()
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if geom_type == "point":
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return Point(ob["coordinates"])
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elif geom_type == "linestring":
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return LineString(ob["coordinates"])
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elif geom_type == "polygon":
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if not ob["coordinates"]:
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return Polygon()
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else:
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return Polygon(ob["coordinates"][0], ob["coordinates"][1:])
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elif geom_type == "multipoint":
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return MultiPoint(ob["coordinates"])
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elif geom_type == "multilinestring":
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return MultiLineString(ob["coordinates"])
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elif geom_type == "multipolygon":
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return MultiPolygon(ob["coordinates"], context_type='geojson')
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elif geom_type == "geometrycollection":
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geoms = [shape(g) for g in ob.get("geometries", [])]
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return GeometryCollection(geoms)
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else:
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raise ValueError("Unknown geometry type: %s" % geom_type)
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def asShape(context):
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"""Adapts the context to a geometry interface. The coordinates remain
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stored in the context.
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"""
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if hasattr(context, "__geo_interface__"):
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ob = context.__geo_interface__
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else:
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ob = context
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try:
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geom_type = ob.get("type").lower()
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except AttributeError:
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raise ValueError("Context does not provide geo interface")
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if geom_type == "point":
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return asPoint(ob["coordinates"])
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elif geom_type == "linestring":
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return asLineString(ob["coordinates"])
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elif geom_type == "polygon":
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return asPolygon(ob["coordinates"][0], ob["coordinates"][1:])
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elif geom_type == "multipoint":
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return asMultiPoint(ob["coordinates"])
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elif geom_type == "multilinestring":
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return asMultiLineString(ob["coordinates"])
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elif geom_type == "multipolygon":
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return MultiPolygonAdapter(ob["coordinates"], context_type='geojson')
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elif geom_type == "geometrycollection":
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geoms = [asShape(g) for g in ob.get("geometries", [])]
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return GeometryCollection(geoms)
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else:
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raise ValueError("Unknown geometry type: %s" % geom_type)
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def mapping(ob):
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"""Returns a GeoJSON-like mapping"""
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return ob.__geo_interface__
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