Monthly Archives: April 2012

Creating polar diagrams with confidence intervals in R

The function r.polar in GRASS GIS allows you to create simple polar diagrams of e.g., the slope aspect or wind directions. These polar diagrams make it easy to spot directional bias, for example in the distribution of the slope aspect … Continue reading

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two-minutes video tutorials for R

I just came across this blog with (by the time of writing) sixty two-minutes video tutorials on how to do things in R. Especially nice for those who like to learn by watching and listening. But do pay attention while … Continue reading

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Creating polar diagrams in GRASS GIS

There are so many functions in GRASS GIS that it is easy to miss one or two. One functions I recently came across through this tutorial is the d.polar function. This function draws a polar diagram of angle map such … Continue reading

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If you run out of memory, split up your data

Most functions of GRASS can handle very large data sets. With a few functions you might run out of RAM though. One of these is the r.random.cell. This is a function that generates a random sets of cells with spatial … Continue reading

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ReshapeGUI – a tool to learn to use reshape2

The package Reshape2 in R is a very powerful tool to flexibly restructure and aggregate data. For users familiar with the pivot table function in Excel or Libreoffice/Openoffice, this tool offers similar (and more) functionality, albeit from the command line. … Continue reading

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