Posts Tagged ‘ GIS ’

Border bias and weighted kernels

August 31, 2012
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Border bias and weighted kernels

With Ewen (aka @3wen), not only we have been playing on Twitter this month, we have also been working on kernel estimation for densities of spatial processes. Actually, it is only a part of what he was working on, but that part on kernel estimation...

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unsupervised classification of a Landsat image in R: the whole story or part two

August 1, 2012
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unsupervised classification of a Landsat image in R: the whole story or part two

The main question when using remote sensed raster data, as we do, is the question of NaN-treatment. Many R functions are able to use an option like rm.NaN=TRUE to treat these missing values. In our case the kmeans function in R is not capable to use such a parameter. After reading the tif-files and creating

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unsupervised classification of a raster in R: the layer-stack or part one.

July 29, 2012
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unsupervised classification of a raster in R: the layer-stack or part one.

In my last post I was explaining the usage of QGis to do a layerstack of a Landsat-scene. Due to the fact that further research and trying out resulted in frustration I decided to stick with a software I know well: R. So download the needed layers here and open up your flavoured version of

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reading shape files in R

June 24, 2012
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reading shape files in R

If I would like to adjust a shape file I normally used the way over an excel file or a text file to get a table and to join this with an existing shape file. Due to the sp and rgdal packages in R you can manipulate shapefiles directly in R: now lets map the

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Mindoro Digital Elevation Map

June 14, 2012
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Mindoro Digital Elevation Map

Saw a map produced by my previous student using a commercial GIS software.Using R raster package and data from diva-gis.org. I produced the same map

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My first R package: zipcode

January 5, 2011
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My first R package: zipcode

My first package, zipcode, is now available on CRAN. It contains the CivicSpace database of 43,191 U.S. zip codes.

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Incremental improvements to Nightlights mapping thanks to R-Bloggers

October 22, 2010
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Incremental improvements to Nightlights mapping thanks to R-Bloggers

The R community is very generous and collaborative. This post walks through the suggestions left by commenters to my previous post on Steve Mosher's Nightlights work, and show the resulting much-improved output.

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Nightlights: cool data, bad geocoding

October 14, 2010
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Nightlights: cool data, bad geocoding

A global source of population density has been on my low-priority wish list for some time, so I was very excited when I found Steve Mosher’s work with the Nighlights data set. “Nightlights” refers to the artificial lights seen from space at night. Astronomers call it “light pollution” which is pretty accurate since it’s decidedly

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Maps with ggplot2

September 27, 2010
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Maps with ggplot2

The ggplot2 package offers powerful tools to plot data in R. The plots are designed to comply with the “grammar of graphics” philosophy and can be produced to a publishable level relatively easily. For users wishing to create a good map without too much thought I would recommend this worksheet. For those without their own

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Free GIS Resources

January 26, 2010
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Free GIS Resources

Over the last couple of days I have utilised some excellent free GIS resources. I have listed these and some others below. Geospatial Analysis: This is the free online version of de Smith, Longley and Goodchild’s excellent book by the same title. It provides full coverage of current GIS methodologies. It also provides extensive information

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