For all following along at home, the PostGIS Cookbook is complete! At 484 pages it’s a tome– but a great one (It’s been out for a few days, actually). A shout out to my brilliant co-authors, Paolo, Bborie, and Tom. I could not have hoped for better. http://www.packtpub.com/postgis-to-store-organize-manipulate-analyze-spatial-data-cookbook/book And for any who wonder, the picture on the front is of the Maumee River, the largest … Continue reading Book Complete
Edit: Free book to the first to tell me what the is name of the children’s book on the armchair in the foreground: Book editing in progress… . Continue reading Editing in progress
Just an image today. Continue reading Drone Pointilism
PostGIS has for a time had ST_DelaunayTriangles for Delaunay Triangulation, and since 2.1 apparently can even natively create a 2.5D TIN using said function, which is pretty cool. I think with SFCGAL, we will eventually have true 3D TINs as well. We’re still waiting on native Vororoi support for PostGIS though. According to http://trac.osgeo.org/postgis/wiki/UsersWikiPostgreSQLPostGIS “GEOS 3.5 is still in development but will have Voronoi which … Continue reading Voronoi in PostGIS
(edited: changed TIN to TIN Z) (edited again — function already exists as a flag in ST_DelaunayTriangles… .) Uh, I wrote a function for nothin’… As Regina points out in the commments, this functionality was rolled into 2.1 with a flag. Her example: For the record, my code is about 2% slower on a dataset that takes ~50minutes to triangulate . —————————————— Original Post —————————————— … Continue reading 2.5D TINs in PostGIS
In my earlier post, I made a claim that SFCGAL was used in this figure: It dawned on my afterwards, while I was using 3D, I hadn’t actually employed any of the analysis goodies that come with SFCGAL. Well, here it is– a footprint as calculated using the view angles and a real terrain model: Here it is compared with the initial calculation: Continue reading UAS (drone) Footprint Geometries Calculated in PostGIS with SFCGAL — for real this time
UAS (drone) Footprint Geometries Calculated in PostGIS (viewed in QGIS nightly), taking into account relative elevation, bearing, pitch, and roll, this time just one: Continue reading UAS (drone) Footprint Geometries Calculated in PostGIS — Individual Footprint
Edit– Code may be flawed, testing—– testing. Please wait to use… . In PostGIS, ST_RotateZ has a couple forms: a version that rotates around 0,0 and a version that rotates around a point of origin: ST_RotateX and ST_RotateY have had no equivalents– until now. These equivalents are dumb versions– they use a transformation/rotation/reverse-transformation to do their magic, which is maybe not as efficient as using … Continue reading Aaargh! No: geometry ST_RotateX(geometry geomA, float rotRadians, geometry pointOrigin)
Thinking out load (and hoping I’m right), but with the classic flight dynamics of roll, pitch, yaw for flight dynamics relative to PostGIS concepts of rotation: Pitch Axis = ST_RotateX Bearing (instead of yaw) = ST_RotateZ using 90-minus the angle for NSEW coordinates from Cartesian angles Roll = ST_RotateY Continue reading Roll, Pitch, Yaw, ST_Rotate
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