Postgis for breakfast: ST_Donut

This post typed into my iPod as an homage. Assisted today by my collegue, J. Stein. Moderate obfuscation of locations is an important technique for the protection of data, say something sensitive like the nesting locations of the very rare and strange fuzzy-bellied gnat catcher. We still want to display the data, but want to make it slightly wrong. A naive approach would place it … Continue reading Postgis for breakfast: ST_Donut

What is the center line of a complex polygon? (cont.)

If we try to extract the centerline of a polygon using Voronoi polygons, like in my previous post, it works pretty well for hydrologic cases, like extracting a stream centerline from stream banks, e.g.: We’ll use this to extract flow lines, in order to build out a better hydrologic network, but also use it to update property boundaries based on deed descriptions which may alternately … Continue reading What is the center line of a complex polygon? (cont.)