Blog Archives

Flood fill a region of an active device in R

July 23, 2014
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Flood fill a region of an active device in R

The following is a function to "flood fill" a region on the active plotting device. Once called, the user will be asked to click on the desired target region. The flood fill algorithm then searches neighbors in 4 directions of the target cell (down, le...

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Automated determination of distribution groupings – A StackOverflow collaboration

May 18, 2014
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Automated determination of distribution groupings – A StackOverflow collaboration

For those of you not familiar with StackOverflow (SO), it's a coder's help forum on the StackExchange website. It's one of the best resources for R-coding tips that I know of, due entirely to the community of users that routinely give expert advise (as...

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Evaluating model performance – A practical example of the effects of overfitting and data size on prediction

May 3, 2014
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Evaluating model performance – A practical example of the effects of overfitting and data size on prediction

Following my last post on decision making trees and machine learning, where I presented some tips gathered from the "Pragmatic Programming Techniques" blog, I have again been impressed by its clear presentation of strategies regarding the evaluation of model performance. I have seen some of these topics presented elsewhere -...

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Decision making trees and machine learning resources for R

April 30, 2014
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Decision making trees and machine learning resources for R

I have recently come across Ricky Ho's blog "Pragmatic Programming Techniques", which seems to be excellent resource for all sorts of aspects regarding data exploration and predictive modelling. The post "Six steps in data science" provides a nice overview to some of the topics covered in the blog. For some reason, this blog does not seem to be...

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Importing bathymetry and coastline data in R

January 25, 2014
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Importing bathymetry and coastline data in R

After noticing some frustrating inaccuracies with the high-resolution world coastlines and national boundaries database found in worldHires from the package mapdata (based on CIA World Data Bank II data), I decided to look into other options. Although listed as "depreciated", the data found in NOAAs online "Coastline Extractor" is a big step forward. There...

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GMT standard color palettes

January 25, 2014
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GMT standard color palettes

GMT (Generic Mapping Tools) (http://gmt.soest.hawaii.edu/) is a great mapping tool. I'm hoping to use it more in the future, but for the meantime I wanted to recreate some of the it's standard color palettes in R. Unfortunately, I couldn't find documen...

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Data mountains and streams – stacked area plots in R

December 9, 2013
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Data mountains and streams – stacked area plots in R

Below are two functions for producing stacked area plots. The first is the more typical approach where sequential series are stacked on top of another (function: plot.stacked), while the second approach is the more aesthetically-oriented version called...

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New version of image.scale function

December 5, 2013
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New version of image.scale function

Below is an updated version of the image.scale function. In the old version, one had to constantly use additional arguments to suppress axes and their labels. The new version contains the additional arguments axis.pos (1, 2, 3, or 4) for defining the s...

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Working with hdf files in R – Example: Pathfinder SST data

November 8, 2013
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Working with hdf files in R – Example: Pathfinder SST data

Following  a question that I posted on stackoverflow.com, I recieved the great advice to use the Bioconductor rhdf5 package to work with HDF5 files. The package is not located on CRAN, but can be sourced from the Bioconductor website: source("http://bioconductor.org/biocLite.R")biocLite("rhdf5") Created by Pretty...

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A first attempt at an individual-based model in R

October 29, 2013
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A first attempt at an individual-based model in R

I have been curious for a while as to how R might be used for the construction of an individually-based model (IBM), or agent-based model (ABM). In particular, what R objects lend themselves best to storing information on individuals, and allow for new...

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