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Stratified random sampling in QGIS
In my previous post I described how you can create a random stratified sampling using GRASS GIS. Unlike in GRASS GIS however, QGIS has a dedicated tool to do this. You can find it under ‘research...
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Import MODIS data in GRASS using r.in.gdal
NASA offers access to its MODIS and ASTER data sets through Reverb|Echo. The data comes in HDF format and uses the Sinusoidal grid tiling system. If your gdal is compiled with HDF4 support (use...
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Check out the new Landcover Polygon overlay function in the LecoS QGIS plugin
The author of the QGIS plugin LecoS came up with a new feature which might come in handy for some of you: a polygon overlay tool. This tool can extract raster values and save them directly to the...
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Improved r.mask in GRASS GIS 7.0
I am mostly using GRASS GIS 7.0, which is the development version. Main reason I started to use this version was the better (faster) vector handling. But there are many other new features and...
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Calculating the raster cell area of an unprojected raster layer
What if you get a raster layer with number of people per raster cell, like for example the population layer from Afripop, and you want to convert it to a population density layer? Well, obviously, you...
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New release candidate for GRASS 6.4.3 is out
The second release candidate of stable release 6.4.3 is available now. It contains a good number of improvements and especially stability fixes, see here for more details.Filed under: GRASS GIS,...
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Looking for a pdf reader with good annotations options
I read my articles on my (Android) tablet or on my computer (Ubuntu 12.10). On both, I want to be able to add notes and underline and highlight text. For Android there are various apps that allow you...
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Find Latitude and Longitude Values in Google Maps
Getting the coordinates of a location on Google maps isn’t as straight forwards as one may expect. But, as usual, if you know how, it is easy enough. And, there are actually several ways. What’s here?...
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Sum up values of neighbouring polygons – a GRASS GIS approach
How to sum up values of neighbouring polygons in QGIS? This question was asked on gis.stackexchange, with two interesting answers. One answer explains how to use Spatialite and SQL to achieve this. The...
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A quick look at the new GRASS Map Swipe Tool
I have just been trying out the new GRASS Map Swipe tool For now it is available in GRASS 7.0 but I understand it will be backported to GRASS 6 after some testing. The tool allows GRASS users to...
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Point coordinates to polygon – part I
Articles about field studies sometimes (but not always unfortunately) contain coordinates delimiting the boundaries of the field study. What if you want to view those boundaries in e.g., Google Earth?...
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Point coordinates to polygon – part II
In my previous article, I showed how you can convert point coordinates into a polygon vector layer in QGIS. So how about GRASS GIS? Like in my previous post, let’s assume you have a text file with two...
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Import GRASS function console output as data.frame in R
In R you can use system calls or the spgrass6 package to run GRASS GIS functions. To do this, you need to run R from within GRASS GIS. This is as simple as starting GRASS GIS and subsequently starting...
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Sharing or exporting sub-sections of a ZIM notebook
I use ZIM desktop wiki to keep all kind of notes. Sometimes I want to share my notes. This is easy enough when I want to share the whole notebook. I simply send the whole folder containing the ZIM...
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Presentation of map query result improved in GRASS 7.0
GRASS GIS (version 6.4, and up to recently 7.0 too) would present map query results in the command console. I have never really got used to it though. Often when I needed to query some points on the...
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Update of the r.forestfrag addon for GRASS GIS
Some time ago I came across this post from Sylla Consult about a script to calculate forest fragmentation index suggested by Riitters et al. (2000). Obviously, it can be used for any land cover type,...
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A plugin to export layers in GIMP file to single pdf file
Update: there is another plugin that export Layers to single multiple pages PDF. You can get the plugin here: http://registry.gimp.org/node/27987. I haven’t tried it yet, so I can’t tell you how it...
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Some cool new features in the upcoming QGIS 2.0
The upcoming QGIS 2.0 will have some really cool and useful new features. Check for example out the latest blog posts by Anita Graser aka Underdark, where she takes you on a tour of all the new...
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GRASS gis scripts to import data from Worldclim, CSFR and PISM
I just came across these GRASS GIS scripts by Julien Seguinot to import multiple files from the WorldClim current climate dataset, the Climate Forecast System Reanalysis (CSFR) data and some other...
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What if Google decides to discontinue Google Scholar?
Since Google discontinued Google reader I have always been wondering; what if they decide to stop with Google Scholar? If you are lucky enough to have access to an university library, you should be...
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