Tag: PostGIS

Analysis, Database, PostGIS, PostgreSQL, SQL

Voronoi in PostGIS

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

Unknown's avatarsmathermather5 Comments
3D, Analysis, Database, Drone, Other, Photogrammetry, PostGIS, PostgreSQL, SQL, UAS

2.5D TINs 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

Unknown's avatarsmathermather6 Comments
3D, Analysis, Database, Drone, Image Processing, Optics, Other, Photogrammetry, PostGIS, PostgreSQL, QGIS, SFCGAL, SQL, UAS

UAS (drone) Footprint Geometries Calculated in PostGIS with SFCGAL — for real this time

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

Unknown's avatarsmathermather3 Comments
3D, Database, PostGIS, PostgreSQL, SFCGAL, SQL

More cutting room floor stuff… — 3D pyramid maker

A little more leftover code from the PostGIS Cookbook— a little tool for making pyramids for SFCGAL enabled PostGIS databases. https://github.com/smathermather/postgis-etc/blob/master/3D/pyramidMaker.sql Edit:  Actually, I think this would work without SFCGAL, but what would be the point… . Edit 2:  Let’s embed some code:   Continue reading More cutting room floor stuff… — 3D pyramid maker

Unknown's avatarsmathermatherLeave a comment
3D, Database, PostGIS, PostgreSQL, SFCGAL, SQL

More cutting room floor stuff… .

ST_3DIntersection performs volumetric intersections for us in PostGIS, if we have SFCGAL enabled for our PostGIS back end.  Much like a normal PostGIS intersection, this is the mathematical definition of an interesection, so it returns the volumetric portion of the intersection, plus 3D linestrings and 3D points and other bits and pieces that qualify for the intersection.  As a little patch, I wrote a quick … Continue reading More cutting room floor stuff… .

Unknown's avatarsmathermather4 Comments
3D, Analysis, Database, Drone, PostGIS, PostgreSQL, SFCGAL, SQL, UAS

O man. Epic 3D on its way. I could drone on and on about #postgis

Still working furiously on final edits for the PostGIS Cookbook.  My last chapter is the last one that the Packt editors and managers are waiting for, but it will be the best I’ve contributed to the book, so I think it will be worth everyone’s time. The trick with this chapter is that when I first wrote it, it was before the heavy lifting the … Continue reading O man. Epic 3D on its way. I could drone on and on about #postgis

Unknown's avatarsmathermather7 Comments
3D, Analysis, Database, PostGIS, PostgreSQL, SFCGAL, SQL

ST_Extrude screen shot: PostGIS with SFCGAL

I have been working a bit to get horao working to visualize PostGIS 3D data.  In the mean time, I have a little work around for viewing 3D extrudes a 3Dish way (i.e. isometric) The nightly build of QGIS now allows you to visualize polyhedral surfaces, the output type of ST_Extrude.  So, I cheated.  ST_Extrude takes 4 parameters: an input geometry, and extrusion along the … Continue reading ST_Extrude screen shot: PostGIS with SFCGAL

Unknown's avatarsmathermather1 Comment