def bbox(coordinates,
crs,
outname=None,
format='ESRI Shapefile',
overwrite=True):
"""
create a bounding box vector object or shapefile from coordinates and coordinate reference system
coordinates must be provided in a dictionary containing numerical variables with names 'xmin', 'xmax', 'ymin' and 'ymax'
the coordinate reference system can be in either WKT, EPSG or PROJ4 format
"""
srs = crsConvert(crs, 'osr')
ring = ogr.Geometry(ogr.wkbLinearRing)
ring.AddPoint(coordinates['xmin'], coordinates['ymin'])
ring.AddPoint(coordinates['xmin'], coordinates['ymax'])
ring.AddPoint(coordinates['xmax'], coordinates['ymax'])
ring.AddPoint(coordinates['xmax'], coordinates['ymin'])
ring.CloseRings()
geom = ogr.Geometry(ogr.wkbPolygon)
geom.AddGeometry(ring)
geom.FlattenTo2D()
bbox = Vector(driver='Memory')
bbox.addlayer('bbox', srs, ogr.wkbPolygon)
bbox.addfield('id', width=4)
bbox.addfeature(geom, 'id', 1)
geom.Destroy()
if outname is None:
return bbox
else:
bbox.write(outname, format, overwrite)
def reproject(self, projection):
srs_out = crsConvert(projection, "osr")
# create the CoordinateTransformation
coordTrans = osr.CoordinateTransformation(self.srs, srs_out)
layername = self.layername
geomType = self.geomType
features = self.getfeatures()
self.__init__()
self.addlayer(layername, srs_out, geomType)
for feature in features:
geom = feature.GetGeometryRef()
geom.Transform(coordTrans)
newfeature = feature.Clone()
newfeature.SetGeometry(geom)
self.layer.CreateFeature(newfeature)
newfeature.Destroy()
self.init_features()
def getProjection(self, type):
"""
type can be either "epsg", "wkt", "proj4" or "osr"
"""
return crsConvert(self.layer.GetSpatialRef(), type)