Using the same LiDAR DEM from which we generated the contours, we can create hillshade tifs using http://www.perrygeo.net/wordpress/?p=7. It compiles easily on a mac, probably even easier on a Linux machine following his directions. Then another simple loop: #!/bin/bash x=0 for f in $( ls *.txt); do x=`expr $x + 1` echo $x $f hillshade $f $f.tif done I’d like this all in a single … Continue reading Hillshade using PerryGeo’s ported GRASS utility
Well, I made some mistakes in the last post, not the least of which is I used the wrong flag for creating an attribute field with elevation. What follows is a little more sophisticated. It takes us from a series of DEM tiles from which I want 2-foot and 5-foot contours (using gdal_contour), and then dumps those shapefiles into PostgreSQL using shp2pgsql. First we prep … Continue reading GDAL Contours (cont.)
Just another quick vignette. From the Ohio Statewide Imagery Program (OSIP) there is a 1-meter DEM for all of Ohio. To get contours from this dataset, one approach is to use GDAL tools, i.e. gdal_contours. As I’m working on a Mac today, I used Kyng Chaos pre-compiled Frameworks: http://www.kyngchaos.com/software:frameworks Then I needed to update my path variable in the BASH shell: export PATH=/Library/Frameworks/GDAL.framework/Programs:$PATH Now we … Continue reading GDAL Contours
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