Articles by dylan

AQP News and Updates

March 12, 2013 | 0 Comments

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...]

Visualizing CA Snow Survey Data in R

January 14, 2013 | 0 Comments

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...]

New AQP Tutorials

January 4, 2013 | 0 Comments

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...]

Basic Simulation of Soil Profile Data in R via AQP

December 19, 2012 | 0 Comments

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...]

Summarizing Circular Data in R: Aspect Angle

October 10, 2012 | 0 Comments

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...]

Compiling Source Packages on R 2.15.x / Mac OS 10.5.x

August 31, 2012 | 0 Comments

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...]

Compiling rgdal on Mac OS 10.5

August 31, 2012 | 0 Comments

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...]

R Quickie: Custom Panel Functions and Default Arguments

April 16, 2012 | 0 Comments

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...]

AQP Kick-Start

March 27, 2012 | 0 Comments

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...]

Dissimilarity Between Soil Profiles: A Closer Look

March 23, 2012 | 0 Comments

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...]

A Graphical Explanation of how to Interpret a Dendrogram

March 15, 2012 | 0 Comments

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...]

AQP / soilDB Demo: Dueling Dendrograms

March 14, 2012 | 0 Comments

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...]

AQP 0.9-9 is ready: 1.0 should be out by 2012-01-01 !

December 22, 2011 | 0 Comments

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...]

Logistic Power Peak (LPP) Simulated Soil Profiles

November 12, 2011 | 0 Comments

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...]
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