Posts Tagged ‘ spatial ’

Continuous dispersal on a discrete lattice

September 27, 2012
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Continuous dispersal on a discrete lattice

Dispersal is a key process in many domains, and particularly in ecology. Individuals move in space, and this movement can be modelled as a random process following some kernel. The dispersal kernel is simply a probability distribution describing the distance travelled in a given time frame. Since space is continuous, it is natural to use

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Notes from A Recent Spatial R Class I Gave

June 19, 2012
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Below is a link to a pdf (compiled with the amazing knitr package) and some accompanying data for a recent short course I gave on basic spatial data import/analysis/visualization in R. The class was only two hours and some of the participants were bein...

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Notes from A Recent Spatial R Class I Gave

June 19, 2012
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Below is a link to a pdf (compiled with the amazing knitr package) and some accompanying data for a recent short course I gave on basic spatial data import/analysis/visualization in R. The class was only two hours and some of the participants were bein...

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Simple Spatial Correlograms for Cross-Country Analysis in R

May 9, 2012
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Simple Spatial Correlograms for Cross-Country Analysis in R

Accounting for temporal dependence in econometric analysis is important, as the presence of temporal dependence violates the assumption that observations are independent units. Historically, much less attention has been paid to correcting for spatial dependence, which, if present, also violates this independence assumption. The comparability of temporal and spatial dependence is useful for illustrating why

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Plot maps like a boss

March 5, 2012
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Plot maps like a boss

A new package OpenStreetMap has been released to CRAN this week which is designed to allow you to easily add satellite imagery, or open street maps to your plots. Raster maps are a great way to add context to your spatial data with a minimum outlay of effort. The syntax in OpenStreetMap is fairly simple, just give

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Spatial correlation in designed experiments

October 20, 2011
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Spatial correlation in designed experiments

Last Wednesday I had a meeting with the folks of the New Zealand Drylands Forest Initiative in Blenheim. In addition to sitting in a conference room and having nice sandwiches we went to visit one of our progeny trials at … Continue reading →

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Shipping Mix

October 20, 2011
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Shipping Mix

With a fresh pile of historical global shipping data, we came back to the flow visualizations that illustrated tangible supply lines that facilitate global trade.  This time we've isolated two types of shipping vessels, cargo and tanker, in order ...

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Hot Spot Mapping in R: Illustrating Relative Seasonal Risk

October 5, 2011
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Hot Spot Mapping in R: Illustrating Relative Seasonal Risk

In recent months, IDV has taken steps to incorporate the powerful statistical engine, R, as a viable connection to Visual Fusion.  R has a robust and growing set of libraries and a community that is constantly thumping away on improvements.  ...

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map.xyz(): interpolation of XYZ data and projection onto a map

May 30, 2011
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map.xyz(): interpolation of XYZ data and projection onto a map

     I am still struggling to get a grasp of R's mapping capabilities. Part of my frustration lies in the fact that I often work on areas near the poles, which complicates interpolation across the 180 degree line. For smaller areas, interpolati...

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R functions for Earth geographic coordinate calculations

May 29, 2011
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R functions for Earth geographic coordinate calculations

Here are some functions that I regularly use for geographic data (e.g. binning, filtering, calculation of new positions etc.).#distance in kilometers between two long/lat positions (from "fossil" package)earth.dist <- function (long1, lat1, long2, l...

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