Submitted by dylan on Wed, 2006-11-01 16:14.
Misc. scanned images from work at the Pinnacles National Monument, in collaboration with the NRCS and NPS.
Submitted by dylan on Mon, 2006-10-23 00:48.
Submitted by dylan on Thu, 2006-09-28 17:27.
Tracking the Unstable distribution of Debian Linux is a nice way to stay on the bleeding edge, while maintaining all of the benefits that a package management system like aptitude has to offer. However, if you happen to be using the NVIDIA kernel module- there is a possibility with each aptitude upgrade that something will break it. Most changes to the kernel-image, or parts of Xorg will result in a broken NVIDIA kernel module- leaving you without a GUI. Fortunately, there is a simple fix: compile the offending kernel module by hand. The Debian tool module-assistant makes this process simple. The entire process is outlined in an excellent article by Andrew E. Schulman here. Essentially, after an NVIDIA-breaking update, re-run the module-assistant snippet, and all should be well.
Submitted by dylan on Thu, 2006-09-07 00:30.
Submitted by dylan on Sun, 2006-07-30 03:04.
OGR ogr2ogr -s_srs 'prj=latlong datum=NAD83' -t_srs '+proj=utm +zone=11 +datum=NAD27' output.shp input.shp ArcToolbox transform from NAD83 GCS to NAD27 UTM Zone 11 (NADCON) ArcToolbox transform from NAD83 GCS to NAD27 UTM Zone 11 (NAD_1927_To_NAD_1983_6 transformation)
Submitted by dylan on Fri, 2006-07-21 23:45.
After a bit of a delay, I have finally migrated all of the USDA-NCSS digital soil survey (AZ, CA, NV), 2005se Tiger, and other misc. data from shapefile format to a PostGIS database. In doing so, seamless access to the entire set of detailed (SSURGO) and generalized (STATSGO) polygon data is now possible through our online soil survey. At the Map unit level, links to adjacent soil polygons, along with a local area calculation are just some of the new possibilities of a spatially-enabled database (PostGIS). Note that DOQQ data is not locally stored for AZ and NV. Clicking on the "print" icon in the map interface at scale of < 1:7000 will fetch DOQQ data from Terraserver in these areas. Also the LandSat mosaic for AZ needs to be re-done with i.landsat.rgb, found in GRASS6.1-CVS. A quick comparison of LandSat channel blending is here. Subsequent changes will include thematic mapping of soil properties and visualizations of difference in soil properties across scales. See a simple summary, in case-study format on the PostGIS website. Thanks to Paul Ramsey for doing the write-up.
Submitted by dylan on Wed, 2006-06-14 00:06.
Submitted by dylan on Fri, 2006-02-03 04:14.
Submitted by dylan on Fri, 2006-02-03 03:37.
Depicting the relative density of sampling can be an interesting task, especially when the points are highly clustered and sparse. Three simple operations that can reveal subtle patterns in the spatial distribution of sample points were explored:
Submitted by dylan on Thu, 2006-02-02 22:32.
Raw LiDAR data is so detailed that localized flow routing algorithms often fail to produce meaningful results. The terraflow algorithm is one such method that appears to work well on such massive grid objects (Homepage).