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 integer value, this gets converted in the overloaded function into a quad_segs version. P.S. I would have written more, but Sherlock just started. Continue reading ST_Buffer diving under the covers part 1
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 leaves it to the user to choose the best available local coordinate system. I should fix this (but I probably won’t just now…). It uses a different function name than you otherwise use for buffering. … Continue reading ST_Buffer for those who want really want all buffer features in geography
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 (@antoniolocandro) January 8, 2016 Ask and ye might receive. Let’s build a function that will take your input geography, how far you want to buffer (in local coordinates) number of segments you want in a quarter, and … Continue reading ST_Buffer for those who want really round geographic circles
Trying out PostGIS 2.2’s ST_ApproximateMedialAxis capabilities today. I’m going to use it to label parcels. So here is my parcel fabric: And here’s what the skeleton of that fabric looks like: It get’s pretty interesting where the parcels are more complicated: more: Oh, the code you say? Well, it couldn’t be much easier: SELECT gid, ST_ApproximateMedialAxis(geom) AS geom FROM cuy_parcel_2015; Or the full version for … Continue reading ST_ApproximateMedialAxis(geom)
Smathermather's Weblog 