[postgis-users] R Based

[Simon Greener]

I had need of a Delaunay Trianguation function for use with PostGIS 2.0.

I found David Leahy's email post and Regine Obe's blog article on a vonoroi article using pl/R and Dr Rolf Turner's deldir package.

My initial function created the delaunay triangles but the triangles were 2D. I needed a function that maintained any Z attribute associated with the XY points passed in to the function.

I contacted Dr Rolf Turner. Rolf changed the base deldir function in the package to maintain any Z or associated value with the XY point set such that the returned triangles still have their Z values.

I have written a short blog article on this which includes the source code.

http://www.spatialdbadvisor.com/postgis_tips_tricks/290/r-based-delaunay-triangulation-function-for-postgis-using-the-deldir-package

Any comments, suggested improvements greatly welcomed.

NOTE: After my initial experience with deldir I installed Jaspa and used its ST_DelaunayTriangles function: it works beautifully and quickly.
But installing a whole replacement spatial type for Postgresql to get access to one function is overkill (and I don't have time to extract just
one function). In addition the solution is problematic due to pl/Java releases being behind PostgreSQL releases. And finally, the manual
nature of installation which while not a problem for me, it is for my less technical customers.

regards
Simon
-- 
Holder of "2011 Oracle Spatial Excellence Award for Education and Research."
SpatialDB Advice and Design, Solutions Architecture and Programming,
Oracle Database 10g Administrator Certified Associate; Oracle Database 10g SQL Certified Professional
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