For a given feature find the closest point along a given path

Question

Looking for a Java based (foss4g) solution for the following:

I am using a path along with a buffer to find features that are along the path. For each of the features returned I want to find the coordinate that is best fit ... meaning a straight line from the feature to the path and gleaning the point on the path.

Answer 1

For Java, I'd recommend JTS Topology Suite. There is both a "Nearest Point" and "Closest Point" routine (I'm not sure if it is the same, or was renamed between versions) that does what you want.

The result from the above is LINESTRING (205 305, 250 300), so the first point of the result is your closest point coordinates, and the length property of the result is the distance.

Answer 2

http://docs.codehaus.org/display/GEOTDOC/Closest+Point+on+a+Line seems to discuss the solution to your problem.

--- update by author of that page --

This page has been ported to sphinx based documentation:

• http://docs.geotools.org/latest/userguide/library/jts/snap.html

That page just goes through how the JTS classes for snapping to a line can be used.