Ok, so the INSERT statements were too numerous for inputing the LiDAR point dataset (about a billion points… .) They kept crashing the postgres daemon. So, I used copy from a CSV file: COPY base.cuy_lidar_all FROM ‘c:/path/cuy_lidar_ground_veg.insert’ WITH CSV Keep your fingers crossed… . Continue reading COPY command psql– loading large LiDAR Point Dataset
A unique constraint implemented as a trigger checking hashed geometry seems like a good idea, that is until I applied it to a multi-10GB dataset. Not surprisingly, it starts off fast on inserts, and slows down a lot as time goes on. So, I thought I’d approach duplicates another way, by deleting them once they exist. So for my table: base.cuy_contours_2 I have hashed my … Continue reading Limitations to Trigger Based Unique Constraint
Below is my metacode for iterating through a grid of images to render the vegetation surface model from povray. The real code will be implemented in BASH and AWK, although this would be a perfect use of Python, if I knew how to use it… . PostGIS Tables: cuy_veg_points: Load veg points into database and make 2D geometry cuy_terrain_points: Load terrain points into … Continue reading Rendering a vegetation surface model using PovRay (cont.)
Early on, I was working on the problem of rendering a virtual forest based on real LiDAR data in order to do things like a detailed, vegetation included, viewshed. There are other things we can do with this data, including discovering the boundary of the canopy (and thus find canopy gaps) and rendering a vegetation surface model. Let’s start with a single tree. If we … Continue reading Rendering a vegetation surface model using PovRay
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