Using Spatial Data in R to Estimate Home Ranges (guest blog post)

(A guest blog post from Dakota Benjamin today, a Case Western Reserve University senior, and 3 year Summer intern we’ve been luck enough to recruit) This post has two big take-aways: using spatial data in R, and applying that knowledge to estimating home ranges. If you are not familiar with the R environment, there are many great resources to familiarizing yourself with this powerful language, … Continue reading Using Spatial Data in R to Estimate Home Ranges (guest blog post)

Plugin-free QGIS TMS tiles via GDAL

Want to load your favorite tiles into QGIS? How about a plugin-free QGIS TMS tiles via GDAL: http://www.3liz.com/blog/rldhont/index.php?post/2012/07/17/OpenStreetMap-Tiles-in-QGIS Really awesome… . Needs but one change: epsg:900913 should be epsg:3857 or QGIS (GDAL?) throws an error. Presumably you could also define epsg:900913 in some config file, but barring that create an XML file as follows, and load as a raster in QGIS: Now I can use … Continue reading Plugin-free QGIS TMS tiles via GDAL

Cleaning animal tracking data — throwing away extra points

Much the problem of the modern era– too much data, uneven data, and yet, should we keep it all? Here’s the problem space: attach GPS collar to a coyote, send that data home, and you have a recipe for gleaning a lot of information about the movement of that animal across the landscape. In order to maximize the data collected while also maximizing the battery … Continue reading Cleaning animal tracking data — throwing away extra points

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

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

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

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

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

PostGIS with SFCGAL — Videos, how did I miss these videos?

The guys from Oslandia are really ripping things up in the PostGIS 3D world.  (They are nice guys too– Olivier and Hugo had a skeletonization approach punched up and ready to test before I left the Boston Code Sprint this past Spring.) So I missed these two videos in my first few views of the SFCGAL website: ————————————————————————————- Just one question– what is “Horoa plugin … Continue reading PostGIS with SFCGAL — Videos, how did I miss these videos?