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Mastering Geospatial Analysis with Python
book

Mastering Geospatial Analysis with Python

by Silas Toms, Paul Crickard, Eric van Rees
April 2018
Beginner to intermediate content levelBeginner to intermediate
440 pages
11h 36m
English
Packt Publishing
Content preview from Mastering Geospatial Analysis with Python

Incidents in a polygon

Our crime database has a polygon area—area commands and beats—as well as incident points. To build a crime dashboard, we want to be able to map incidents within a specific area command or beat. We can do that by using JOIN and ST_Intersects. The following code shows you how:

cursor.execute("SELECT ST_AsGeoJSON(i.geom) FROM incidents i JOIN areacommand acmd ON ST_Intersects(acmd.geom, i.geom) WHERE acmd.name like'FOOTHILLS' and date >= NOW() - interval '10 day';")crime=cursor.fetchall()for x in crime:    layer=json.loads(x[0])    layergeojson=GeoJSON(data=layer)    map.add_layer(layergeojson)

The previous code selects the geometry from incidents as GeoJSON (ST_AsGeoJSON(i.geom) from incidents), where the incident ST_Intersects ...

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Publisher Resources

ISBN: 9781788293334Supplemental Content