Feeding Schedule While on paternity leave I had an opportunity to test out periodic smoothing splines (within the framework of generalized additive models) on an interesting time-series-- an infant's feeding schedule. read more [Read more...]

The AQP family of R packages has seen a lot of development over the last 3 months. Some of the highlights include: HTML manual pages with syntax-highlighting and figures, c/o knitr new vignettes: "dealing with bad data", gridded SSURGO (gSSURGO) demo,... [Read more...]

The CDEC website provides access to a wide range in hydrologic data (stream flow, snow survey, etc.) collected in California. The following code and functions (attached at the bottom of the page) illustrate how to query CDEC, and graphically compare th... [Read more...]

Soil Series Extent Several new AQP-related tutorials have been posted to the R-Forge project page. SoilProfileCollection class/method documentation soil series extent mapping examples read more [Read more...]

Something fun to play with before the new year: experimental code in aqp for simulating soil profile data from a single "template" profile. The basic idea: simulate horizon thickness data using a family of Gaussian functions with mean defined by horizo... [Read more...]

The orientation of terrain surface (aspect) can have dramatic effects on landscape-scale variation in soil temperature and moisture. Summarizing aspect angle is complicated by the fact that sampled values are measured on a circular scale. The circular ... [Read more...]

For some reason R is not happy with its 64-bit cousin when installing source packages: * installing *source* package ‘XMLSchema’ ... ** R ** inst ** preparing package for lazy loading ** help *** installing help indices ** building package indices ** installing vignettes ** testing if installed package can be loaded *** arch - i386 *** arch - x86_64 /Library/Frameworks/... [Read more...]

Why do I always forget how to do this? R CMD INSTALL rgdal --configure-args="--with-gdal-config=/Library/Frameworks/GDAL.framework/Versions/Current/unix/bin/gdal-config --with-proj-include=/Library/Frameworks/PROJ.framework/Versions/4/Headers/ --with-proj-lib=/Library/Frameworks/PROJ.framework/Versions/Current/unix/lib/" You will need to adjust the paths based on your ... [Read more...]

A proper introduction to the soilDB package is now available here. Installation and basic usage are covered. More detailed, task-specific documentation on aqp and soilDB will be available soon. read more [Read more...]

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... [Read more...]

Mapping near Paloma, CA This image has nothing to do with the following content. A quick example of how to use the USDA-NRCS soil data access query facility (SDA), via the soilDB package for R. The following code describes how to get component-level so... [Read more...]

Sometimes the basic functionality in lattice graphics isn't enough. Custom "panel functions" are one approach to fully customizing the lattice graphics system. Two examples are given below illustrating how to define an (inline) custom panel function fo... [Read more...]

A fun kick-starter for anyone interested in working with soil profile data in R, via AQP. See in-line comments for details. Up next, profile slicing and aggregation. read more [Read more...]

Continuing the previous discussion of pair-wise dissimilarity between soil profiles, the following demonstration (code, comments, and figures) further elaborates on the method. A more in-depth discussion of this example will be included as a vignette w... [Read more...]

Dendrograms are a convenient way of depicting pair-wise dissimilarity between objects, commonly associated with the topic of cluster analysis. This is a complex subject that is best left to experts and textbooks, so I won't even attempt to cover it her... [Read more...]

Previously, soil profile comparison methods from the aqp package only took into account horizon-level attributes. As of last week the profile_compare() function can now accommodate horizon and site-level attributes. In other words, it is now possible t... [Read more...]

Here is a quick, draft demo on extracting soils data from a PedonPC database, and performing some common analysis with functions from AQP. The newly released soilDB package makes it possible to rapidly extract soils data from PedonPC, local NASIS, and ... [Read more...]

Here is a quick demo of some of the new functionality in AQP as of version 0.99-9.2. The demos below are based on soil profiles from an archive described in (Carre and Girard, 2002) available on the OSACA page. A condensed version of the collection is ... [Read more...]

Version 1.0 of AQP is nearly ready-- after nearly 3 years of development, 2 years on R-Forge, and 1+ year on CRAN. Just pushed version 0.9-9 to R-Forge, and it should be on CRAN within a couple days. Recent changes are listed below, clipped from the NE... [Read more...]

A friend of mine recently published a very interesting article on the pedologic interpretation of asymetric peak functions fit to soil profile data (Myers et al., 2011). I won't bother summarizing or paraphrasing the article here, as the original artic... [Read more...]