Posts Tagged ‘ Dylan ’

Extracting an image chunk from a collection of Large MrSid Images

June 4, 2012
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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...

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soilDB Demo: Processing SSURGO Attribute Data with SDA_query()

April 26, 2012
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soilDB Demo: Processing SSURGO Attribute Data with SDA_query()

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...

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AQP Kick-Start

March 27, 2012
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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

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Dissimilarity Between Soil Profiles: A Closer Look

March 23, 2012
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Dissimilarity Between Soil Profiles: A Closer Look

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...

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A Graphical Explanation of how to Interpret a Dendrogram

March 15, 2012
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A Graphical Explanation of how to Interpret a Dendrogram

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...

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AQP / soilDB Demo: Dueling Dendrograms

March 14, 2012
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AQP / soilDB Demo: Dueling Dendrograms

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...

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AQP Demo: Interfacing with PedonPC Databases using the ‘soilDB’ Package

January 12, 2012
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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 ...

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A Quick Demo of SoilProfileCollection Methods and Plotting Functions

January 4, 2012
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A Quick Demo of SoilProfileCollection Methods and Plotting Functions

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 ...

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

December 22, 2011
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AQP 0.9-9 is ready: 1.0 should be out by 2012-01-01 !

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...

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Logistic Power Peak (LPP) Simulated Soil Profiles

November 12, 2011
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Logistic Power Peak (LPP) Simulated Soil Profiles

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...

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