What is the center line of a complex polygon? Routing Stream and Rivers Part Two
The series and one additional example: Continue reading What is the center line of a complex polygon? Routing Stream and Rivers Part Two
Tag: FOSS
What is the center line of a complex polygon? Routing Stream and Rivers
Continuing my posts on the centerline of a complex polygon (you can work your way backward from here), here’s it’s application to a riverine system (legend: light blue river, black centerline derived from routing through the skeleton of voronoi polygons from a densified stream bank set + the skipped skeleton bits in pink– read through the series if you if you don’t grok that explaination): Continue reading What is the center line of a complex polygon? Routing Stream and Rivers
Proper (ab)use of a database, contour interpolation using #postgresql #postgis #arcgis
Anyone who has been following along at home knows I don’t think much like a DBA. Sometimes that’s good; mostly it’s probably bad. In this post, I hope it will be interesting. The problem of the day is how to take engineering contours derived from breaklines, a lidar point cloud, and all the lot, and do a good job interpolating that to a DEM. This … Continue reading Proper (ab)use of a database, contour interpolation using #postgresql #postgis #arcgis
What is the center line of a complex polygon? Routing as the solution
I’ve had a series of posts (including this one) on finding the center line of a complex polygon– especially with an interest in finding the center line of streams and river bodies. We have to give credit to my colleague Tom Kraft for solving the polygon centerline problem. Tom struck upon the very elegant solution– derive the medial axis, and then use a few end … Continue reading What is the center line of a complex polygon? Routing as the solution
Independence– Free as in Freedom, part II
A friend of mine read my first post “Independence– Free as in Freedom” and said this: “awesome blog and great post. did jack respond?” My response: “Nooo. I think I’m unknown in the ESRI world …. But it was a heartfelt post. I think Jack has changed the world, but recognize it has changed him. I’m pulling for that organization to radically re-invent itself. The … Continue reading Independence– Free as in Freedom, part II
Serving and filtering #GeoJSON from #GeoServer
The nice thing about setting up something like GeoServer, which is so feature rich, is when you need to pivot based on the demands of a new project, the technical infrastructure is already there, just waiting to be configured or turned on. The case today: feature services. Someone wants to use my existing infrastructure in a new application. I typically serve tile services. One checkbox … Continue reading Serving and filtering #GeoJSON from #GeoServer
Using Quantum GIS for real work…
I have long lived in the desktop realm of ESRI, and expect ESRI products to be a part of my workflow for a long time to come. But, the time has come to delve in deeply with Quantum GIS. I’ve read from many sources that it has come of age as a desktop GIS. I tried it 4 years ago, along with its competitors in … Continue reading Using Quantum GIS for real work…
Independence– Free as in Freedom
I recently gave a talk on a really interesting project I’m working on, and in the process of talking to a non-technical crowd introduced Open Source using some of my favorite (borrowed) phrases, i.e. “Free not as in free beer, but free as in freedom, free as in ‘free puppy’”, which resulting in a surprisingly satisfying chuckle from the audience. What’s great about the project … Continue reading Independence– Free as in Freedom
Cartographically Pleasing Vegetation Boundaries– with PovRay, PostGIS, and LiDAR
Just pretty pictures today. Continue reading Cartographically Pleasing Vegetation Boundaries– with PovRay, PostGIS, and LiDAR
Cartography and USGS — Fake Building Footprints in PostGIS now with distance operator (part 2)
In a previous couple of posts (this one, and this one), we dealt with point rotations, first with bounding box searches, and then with nominal use of operators. First we create a function to do our angle calculations, then use select to loop through all the records and do the calculations. Within our function, first we find our first (in this case) five nearest streets … Continue reading Cartography and USGS — Fake Building Footprints in PostGIS now with distance operator (part 2)
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