Recently needed to extract a small "chunk" from a collection of adjacent MrSid mosaics, each about 4Gb in size. Once again, GDAL came to the rescue, and saved much time and agony wile working with very large, compressed, and proprietary-format files. T...
Posts Tagged ‘ Open Source GIS and Mapping Ideas ’
PostGIS Quickie
Today I needed to cut out a rectangle of geologic data from a state-wide map in an AEA coordinate system, using a bounding box from a UTM zone 10 region, with the output saved in UTM zone 10 coordinates. PostGIS makes this type of operation very simple...
Soil Series Query for SoilWeb
A map depicting the spatial distribution of a given soil series can be very useful when working on a new soil survey, updating an old one, or searching for specific soil characteristics. We have recently added a soil series query facility to SoilWeb, w...
Terrain Classification Experiment 2: GRASS, R, and the raster package
Quick post on terrain classification, based on some trouble folks were having with a previous example on Windows. With the spgrass6 package, raster stacks are created by loading several GRASS files at once: x <- readRAST6(vname=c('beam_sum_m...
First-Cut Approach to Synchronizing Field Notes with GPS Data
After a week's worth of work in the field, I typically have several pages of hand-written field notes that are associated with GPS waypoints-- badly in need of some kind of transcription/organization. I have yet to find a simple approach for bringing t...
Visualizing Terrain Surface Indicies with Scaled Arrows
Hamish Bowman recently posted a new GRASS module (d.barb) that can be used to depict the direction and magnitude components of some vector (e.g. wind field) along a raster surface or at points in space. An example (c/o Hamish): read more
Tips for Using our Google Earth Interface to SoilWeb
GE SoilWeb Demo The folks in Lincoln recently changed the links to the OSDs from http:// to https:// style URLs... which seems to cause problems for new versions of Google Earth. I have noticed that when clicking on soil profile sketches an error is re...
Customizing Maps in R: spplot() and latticeExtra functions
I recently noticed the new latticeExtra page on R-forge, which contains many very interesting demos of new lattice-related functionality. There are strong opinions about the "best" graphics system in R (base graphics, grid graphics, lattice, ggplot, et...
AQP Examples: Profile Visualization
Two examples of the output from the profile_plot() function, using data from the Sierra Foothill Region, CA. read more
Soil Properties Visualized on a 1km Grid
Fresno Area Urban Areas vs Irrigated LCC: grey regions are current urban areas A couple of maps generated from a 1km gridded soil property database, derived from SSURGO data where available with holes filled with STATSGO data. Soil properties visualize...
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
