Geoprocessing

Geoprocessing Functions

Functions with geometries:

Function	Description	Syntax
Area	Area of polygon	geom.area
Bounds	Geometry extent: minX, minY, maxX, maxY	geom.bounds
Length	Length of geometry	geom.length
Centroid	Centroid of geometry	geom.centroid
Buffer	Buffer	geom.buffer('width')
Distance	Distance between two geometries	geom1.distance(geom2)
Intersection	Provides the overlapped area	geom1.intersection(geom2)
Union	Union of geometries, separating the overlapped area	geom1.union(geom2)
Cascading Unions	Union of a list of geometries, separating the overlapped area	cascaded_union([geom1, geom2, geom3...])
Difference	Erases the overlapped area	geom1.difference(geom2)
SymDifference	Erases the non-overlapped area	geom1.symmetric_difference(geom2)

Example

import fiona
import shapely.geometry as shp

sch = {'geometry': 'Polygon',
       'properties': {'Area': 'float:13.3'}}

data1_shp = r'C:\Data\data1.shp'
data2_shp = r'C:\Data\data2.shp'
targt_shp = r'C:\Data\target.shp'

with fiona.open(targt_shp, 'w', driver='ESRI Shapefile', schema=sch) as output:

    for feat1 in fiona.open(data1_shp):
        geom1 = shp.shape(feat1['geometry'])

        for feat2 in fiona.open(data2_shp):
            geom2 = shp.shape(feat2['geometry'])

            if geom1.intersects(geom2):
                interc = geom1.intersection(geom2)
                area = interc.area

                output.write({'geometry': shp.mapping(interc),
                              'properties': {'Area': area}})