Soil survey data are typically built upon a foundation of soil-landscape relationships that have been verified in the field.

The AQP family of R packages has seen a lot of development over the last 3 months. Some of the highlights include:

1. HTML manual pages with syntax-highlighting and figures, c/o knitr
2. new vignettes: "dealing with bad data", gridded SSURGO (gSSURGO) demo, and "aggregating properties by bedrock kind"
3. a new package called sharpshootR containing misc. functions to support soil survey
4. slab() has been re-written and is now much more efficient (with memory), transparent (10x fewer lines of code), and "slab functions" are much simpler to write.

Soil Series Extent

Several new AQP-related tutorials have been posted to the R-Forge project page.

1. SoilProfileCollection class/method documentation
2. soil series extent mapping examples

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 horizon thickness values found in the template and standard deviation defined by the user. Larger hz.sd values will yield more drastic variation in the simulated results. Note that only "horizonation" (e.g. the sequence of horizons and their respective thickness) is simulated; horizon attributes (e.g. texture, pH, etc.) are copied from the "template" profile.

Basic usage is demonstrated below, see package manual page for details. This function is only available in the version of aqp hosted by R-Forge. It should be on CRAN by the new year.

Simulated Profiles

Automated OSD lookup and display

 
UPDATED 2013-04-08


This functionality it now available in the soilDB and sharpshootR packages. All code on this page is now superseded by the fetchOSD() and SoilTaxonomyDendrogram() functions.

 
UPDATED 2012-11-07

I have been thinking about a URL-based interface to basic Official Soil Series Description (OSD) data for a while now... something that when fed a URL, would return CSV-formatted records to the calling process. These type of interfaces can later be used to support more complicated systems, such as our smartphone interface to SoilWeb. URLs can be accessed like files in R, making it possible to do something like this:

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.

Here is a quick demonstration of how functionality from the AQP package can be used to answer complex soils-related questions. In these examples the profileApply() function is used to iterate over a collection of soil profiles, and compute several metrics of soil development:

• depth of maximum clay content
• clay/RF content within the PCS
• clay content within the argillic horizon
• thickness of argillic horizon
• depth to argillic horizon

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 soils data for Yolo County (survey area CA113) from SDA and compute representative sub-order level classification for each map unit. This example requires an understanding of SQL, US Soil Taxonomy and the SSURGO database.

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.

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 within the 1.0 release of AQP.

Profile Dissimilarity Demo: MVO Soils