def dissolve(sourcefile, sinkfile, key, unsplit=None):
try:
shape
except NameError:
raise NotImplementedError("dissolve require shapely")
with fiona.drivers():
with fiona.open(sourcefile) as source:
schema = source.schema
schema['properties'] = {key: source.schema['properties'][key]}
with fiona.open(sinkfile,
'w',
crs=source.crs,
schema=schema,
driver=source.driver) as sink:
gotkeys = dict()
for _, feat in source.items():
fkey = feat['properties'][key]
fshape = shapelyshape(feat['geometry'])
if fkey in gotkeys:
gotkeys[fkey][0] = gotkeys[fkey][0].union(fshape)
else:
gotkeys[fkey] = [fshape]
for shapelist in gotkeys.values():
if unsplit:
for s in disjointed(shapelist):
sink.write(s)
else:
sink.write(shapelist[0])
def area(feature):
try:
geom = shapelyshape(feature['geometry'])
return geom.area
except NameError:
raise NotImplementedError("length requires shapely")
def length(feature):
'''Returns shapely length'''
try:
geom = shapelyshape(feature['geometry'])
return geom.length
except NameError:
raise NotImplementedError("length requires shapely")
def shape(feature):
'''Applies shapely.geometry.shape to the geometry part of a feature
and returns a new feature object with properties intact'''
try:
return {
'properties': feature.get('properties'),
'geometry': shapelyshape(feature['geometry'])
}
except NameError:
raise NotImplementedError("shapify requires shapely")
def shapes(filename, crs=None):
'''
Generator that yields a Shapely shape for every feature in a layer.
'''
try:
shapelyshape
except NameError:
raise NotImplementedError("length require shapely")
with fiona.drivers():
with fiona.open(filename, 'r') as layer:
if crs is not None:
def _geom(feature):
return fiona.transform.transform_geom(
layer.crs, crs, feature['geometry'])
else:
def _geom(feature):
return feature['geometry']
for feature in layer:
yield shapelyshape(_geom(feature))