Photogrammetric like ortho-photos rendered with GDAL/PostGIS from 3D point clouds created in Bundler and PMVS? Yes indeedeedoo: Point cloud in meshlab: And “orthophoto” derived from voronoi polygons in PostGIS, rendered to tif with gdal: Hat tip to my3dscanner for making it so easy to generate the point cloud. More on this later. Continue reading Photogrammetry using Bundler, PMVS, GDAL, and PostGIS.
I was playing recently with techniques for making text/labels in maps more readable in a map. We can use simple buffers to do this, but this isn’t always adequate. Take this example: which is a label on top of contours. It is adequately readable. If we show 2 ft contours as well, the map becomes somewhat cluttered: So, we apply the common technique of halo … Continue reading Cartographic tricks and tips– making text readable.
Michael Byrne (@byrne_tweets), the Geospatial Information Officer (GIO) for the Federal Communications Commission (FCC) has been tweeting out queries like this: “@tmcw @vtcraghead @SeanGorman so if you could design an open data initiative in govt, what would you do? “ to which he has gotten everything from <140 character responses from e.g. Bill Morris of: @byrne_tweets Nationalize the high-res imaging satellites! Oh sorry – You got me … Continue reading Architecture of an Open Data Initiative, Fed Style
Just discovered ST_Node, a function in PostGIS just for noding geometries. I used to use ST_Union for this, a potentially memory intensive operation. Now I can use ST_Node. For usage, see the PostGIS docs (requires 2.0 and GEOS 3.3.2 for bug free use). Back to coding. That is all. Continue reading Using ST_Node in PostGIS (where once I used ST_Union)
In previous posts [1] and [2] I talk about identity crises in GIS/Geospatial world related to real economic changes in the way the geospatial sector is structured. Comments have been many, but it seems that (my fault here) it quickly devolved into Planning GIS vs. Spatial IT (after all, I was responding to Paul Ramsey’s meme), in other words IT vs. Planning, and the cultural … Continue reading What is GIS? (continued again!)
Sadly, I cannot post the code for this one, but will post the images– playing with tesselation in PostGIS today: Continue reading Tesselation of Hexagons in PostGIS
TileStache (and some adaptation of great pre-built cartography from others more artful than I) results in this: Continue reading Compositing in TileStache
Who knew? Not I! I shouldn’t confess, but just discovered multi-line comments in PostgreSQL: Sadly, WordPress syntax highlighting doesn’t recognize this… . I think I can muddle through without it though. Continue reading Multi-line Comments in SQL for PostgreSQL
In the previous post, I cite Paul Ramsey, Brian Timoney, and James Fee’s various posts on changes in the geospatial sector. Paul responded with a great post refining his position on Spatial IT vs. GIS. Due to my argumentative academic training, I can’t leave well enough alone. Besides, I said I’d follow up on Brian’s post, and the following does so, at least indirectly. Paul … Continue reading What is GIS? (continued)
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