def hully(g_list):
from django.contrib.gis.geos import GEOSGeometry
from django.contrib.gis.geos import MultiPoint
from django.contrib.gis.geos import GeometryCollection
# maybe mixed bag
types = list(set([g['type'] for g in g_list]))
# should work for any combination
try:
hull = GeometryCollection(
[GEOSGeometry(json.dumps(g)) for g in g_list]).convex_hull
except:
print('hully() failed on g_list', g_list)
# buffer points, but only a little if near meridian
if len(types) == 1 and types[0] == 'Point':
l = list(set([g_list[0]['coordinates'][0] for c in g_list[0]]))
if len([i for i in l if i >= 175]) == 0:
hull = hull.buffer(1)
else:
hull = hull.buffer(0.1)
return json.loads(hull.geojson) if hull.geojson != None else []
def vector_catalog_translate_features(request, old_layer, new_layer):
first = timeit.timeit()
features = VECTOR_LAYERS[old_layer]['geometries_by_id'](
request.data['features'])
geometries = [g for g, props in features]
second = timeit.timeit()
union = GeometryCollection(*geometries).unary_union
bbox = union.envelope
import math
unit = math.sqrt(bbox.area) / 40
simpler = union.buffer(unit)
# print bbox, unit, union.area, len(union.wkt), len(simpler.wkt)
third = timeit.timeit()
response = Response(VECTOR_LAYERS[new_layer]['features_by_wkt'](
simpler.wkt # bbox.wkt
))
fourth = timeit.timeit()
print "retrieve geoms: ", second - first
print "union: ", third - second
print "retrieve features: ", fourth - third
return response
