Submitted by dylan on Mon, 2007-06-11 06:40.
Submitted by dylan on Mon, 2007-06-11 01:58.
A simple example of how to use R to perform interpolation with ordinary kriging, using data from a text file. This example makes use of the gstat library for R. Additional examples of how to use the following gstat functions are included:
- variogram maps
- directional variogram plots
- ploting the interpolated surface directly from R
Note that this example is not meant to be an authoritative guide on variogram selection, or proper modeling of anisotropy-- just an example. The Kansas Geological Survey has an interesting set of reports that illustrate selection of a directional variogram in the presence of a strong, regional trend.
Submitted by dylan on Wed, 2007-06-06 23:00.
Many of the examples used in this demonstration are now somewhat dated, probably inefficient, and in need of revision. I'll spend some time on an updated version for the GRASS wiki soon.
A simple example of how to use GRASS+R to perform interpolation with ordinary kriging, using data from the spearfish sample dataset. This example makes use of the gstat library for R.
- Issaks, E.H. & Srivastava, R.M. An Introduction to Applied Geostatistics Oxford University Press, 1989
- GSTAT Manual
- GSTAT Examples
Submitted by dylan on Sun, 2007-06-03 00:22.
Submitted by dylan on Wed, 2007-05-16 22:00.
Submitted by dylan on Mon, 2007-02-19 23:44.
Working with DBF files
- Extract the text contents of a DBF file with dbfxtrct, select out the 3rd and 2nd columns with awk, keep only unique rows with sort and uniq, and finally saving to a new file called 'ca_fips-name_list.txt' with shell redirection.
Submitted by dylan on Mon, 2007-01-29 23:00.
Note that this is a bit out of date, since several errors have been corrected. (update pending)
Submitted by dylan on Sat, 2007-01-27 03:00.
PINN Pano 1: Recent burn area.
Submitted by dylan on Sat, 2007-01-27 02:03.
Two illustrations describing the progress over time for two tasks: the collection of pedon data in the field, and the input of this data into PedLogic. Number of pedons associated with individual workers are summarized by day. Note that data was usually collected in teams. Click on figures for larger version.
Submitted by dylan on Wed, 2007-01-17 23:28.
Google Earth provides a flexible and open ended vizualization system for geographic data. We intend to present PINN soils data thorugh our own, 2 dimensional, interface (to avoid dependence on a quasi-free setup like GE). However, there are considerable extra features that can be added onto our presentation of the data through GE. For example, synthesized pedon data, photographs, and even geologic diagrams can be presented to the user in a 3D environment with little work on our end: we have the data, GE does the hard work of presenting it in 3D. Some early examples of what this might be like, along with links to the actual data, are presented below. Download GE and our data to give it a try for yourself.