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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

Intersecting lines

You know the length of the lines, and by drawing the lines in a Jupyter Notebook, you know that lines 1 and lines 3 intersect. In PostGIS, you can use the ST_Intersects() function, passing either geometries or geographies. The database will return either true or false.

The following code will execute the query on lines 1 and lines 3 and return True:

cu.execute("SELECT ST_Intersects(l.location::geography,ll.location::geometry)            FROM lines l, lines ll WHERE l.id=1 AND ll.id=3")cu.fetchall()

The previous code will return True, because lines 1 and lines 3 intersect. But where do they intersect? Using ST_Intersection() will return to the point where the two lines meet:

cu.execute("SELECT ST_AsText(ST_Intersection(l.location::geography, ...
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Publisher Resources

ISBN: 9781788293334Supplemental Content