43 lines
1.6 KiB
Python
43 lines
1.6 KiB
Python
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from pygeoif.geometry import mapping
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from shapely.geometry import shape
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def merge_features(geojson, condition, aggregate={}):
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"""Merge the geometries using shapely's union for all the geojson's features that
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meet the condition, condition get's passed an item of feature. Then aggregate the properties
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in the aggregate dict using a function that get as input the list of property values off alle
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matched features. Operates inplace."""
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indices = [index for index, feature in enumerate(geojson['features']) if condition(feature)]
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if len(indices) == 0: # also if there is one index, we
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return geojson
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properties = {
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prop: agg([
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properties_[prop]
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for index in indices
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for properties_ in [geojson['features'][index]['properties']]
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if prop in properties_
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])
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for prop, agg in aggregate.items()
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}
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properties.update({
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key: value
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for index in indices
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for key, value in geojson['features'][index]['properties'].items()
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if key not in aggregate
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})
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if len(indices) == 1:
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geojson['features'][indices[0]]['properties'] = properties
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return geojson
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union = shape(geojson['features'][indices[0]]['geometry'])
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for index in indices[1:]:
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union = union.union(shape(geojson['features'][index]['geometry']))
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for index in indices[::-1]: # reverse, such that the 'todo' indices willnot change.
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del geojson['features'][index]
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geojson['features'].append({
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'geometry': mapping(union),
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'properties': properties
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})
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return geojson
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