Well, I made some mistakes in the last post, not the least of which is I used the wrong flag for creating an attribute field with elevation. What follows is a little more sophisticated. It takes us from a series of DEM tiles from which I want 2-foot and 5-foot contours (using gdal_contour), and then dumps those shapefiles into PostgreSQL using shp2pgsql. First we prep … Continue reading GDAL Contours (cont.)
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
For a variety of reasons, I want to load my whole LiDAR vegetation dataset into PostGIS. I have it in raw, unclassified LAS files, and broken into classified, space delimited text files as well. The unclassified LAS is nice, if I ever want to hone the data, but for now, we’ll assume the classified data are correctly classified by someone smarter than I am (a … Continue reading Loading LiDAR data in PostGIS
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