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New PostGIS book, on its way…
I have posted about this previously, but just a reminder that I am working (with dedicated and brilliant co-authors) on a PostGIS book! Publication date TBD, but we are not far off now. It will be via...
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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...
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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....
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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...
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Editing in progress
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… .
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The easiest way to get PostGIS and friends running:
Docker. See: https://github.com/vpicavet/docker-pggis for a quick and easy Docker running PostGIS. Understand, this isn’t production ready (the connection permissions make my teeth hurt a little) but,...
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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...
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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… ....
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Drivetime analyses, pgRouting
We’ve got some quick and dirty pgRouting-based code up on github. I say quick and dirty because it directly references the table names in both of the functions. I hope to fix this in the future. The...
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Airspace is complicated — and so I abuse PostGIS once again
Let’s ignore for a moment the drone hobbiest / enthusiast. What is the shape of airspace for airplanes and commercial and government unmanned aircraft flying under Certificates of Authorization, and...
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Airspace is complicated — and so I abuse PostGIS once again — Reprise…
In the previous post: http://smathermather.wordpress.com/2014/10/25/airspace-is-complicated-and-so-i-abuse-postgis-once-again/ we explore the 3D shape and complexity of controlled airspace. Now here’s...
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Airspace — A deep rabbit hole
In previous maps we looked at Class B, C, and D airspace. Let’s add in Class E0 and E5… (not yet in 3D): (Map tiles by Stamen Design, under CC BY 3.0. Data by OpenStreetMap, under ODbL) Map showing...
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Editing in progress
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… .
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Normalizing tables in PostgreSQL: experiments with Fulcrum
Fulcrum by Spatial Networks is an interesting and very useful hosted service for collecting geo data in the field with whatever smartphone or tablet you already own. It works well, so long as you just...
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ST_Buffer for those who want really round geographic circles
A little functionality request from @antoniolocandro on twitter: ST_buffer for geography has no option for quad_segs, alternative so buffer looks nice not jagged? cc @smathermather — Antonio Locandro...
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ST_Buffer for those who want really want all buffer features in geography
My previous post on improving buffering geography in PostGIS has three disadvantages: It doesn’t do this at a low enough level to automatically use the best available local coordinate system. This...
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ST_Buffer diving under the covers part 1
This will be a quick post. I just looked at how ST_Buffer is written in the PostGIS codebase, and I thought this was interesting. When you use ST_Buffer and specify geometry, buffer distance, and an...
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Final?: ST_Buffer on Geography, or My love for @NullIsland
Thanks to Paul Norman’s reminder in a previous post, we now have all the pieces we need to complete an ST_Buffer function that exposes all the wonderful goodness of buffer style parameters to geography...
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ST_Buffer on Geography — Iteration
In my previous post, Imagico said: This is nice but still fails in one important aspect – it will create significant inaccuracies once your buffering distance reaches values where buffering in a single...
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Yet another approach to ST_Buffer on geography
Another approach to ST_Buffer would be to subdivide the geometries before buffering, and put them all together at the end. ST_SubDivide can do this for us. We can tell it how may vertices we want in...
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