Monthly Archives: March 2012

Sexante toolbox for QGIS

QGIS already has very strong analytical capabilities through its GRASS toolbox. Now, this is further extended by a new plugin that offers direct access to the Sextante toolbox. With this toolbox, QGIS can tap into 300+ functions from SAGA GIS … Continue reading

Posted in GIS, GRASS GIS, QGIS | Tagged , , , , , , | 1 Comment

How to reduce PDF file size in Linux

I have a scanned report of 181 pages, resulting in a 20MB file. Still OK, unless you need to share the document with a very slow internet connection.

In comes Gostscript, a command line tool that can read and manipulate pdfs. On eHow, you can find a short tutorial how to do this.

 

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Update of GADM datasets

It is always good to keep an eye on your data sources if you don’t want to miss out on new versions. Like the Global Administrative Areas database (GADM), which published version 2 of their data set earlier this year … Continue reading

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Changes in the r.mapcalc syntax in GRASS GIS 7

After some frustrating failed attempts to do some simple raster calculations in GRASS (version 7.0), I found out there is a small change in the syntax for r.mapcalc in GRASS GIS 7:

Posted in GRASS GIS | Tagged , , | 1 Comment

Create mobile maps

Outdoor sport or field work, a GPS has become indispensable. But what if you want to use your own maps? If you are using an Android smartphone and one of the map viewers available on android market, this is fairly … Continue reading

Posted in Android, GIS, Mobile tools | Tagged , , , , , , | 4 Comments

Add geometry values to vector layer in GRASS GIS

In my previous post I explained how to add geometry values to the attribute table of a vector map in QGIS. You can do the same in GRASS GIS. It is slightly more complicated (don’t worry, it is still easy … Continue reading

Posted in Data handling, GIS, GRASS GIS | Tagged , , , , , | 1 Comment

Adding geometry columns to attribute table of vector map

What if you have a vector polygon layer and you want to add a column to the attribute table with the size (area) of each individual polygon? Very simple in QGIS, just go to the vector menu: vector | Geometry … Continue reading

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Another way to import OSM data in your PostGIS database

There are various options to import your data in a PostGIS database. The OSM2postgresql script (for Linux) sets up a PostgreSQL / PostGIS server or database (optional), imports OSM data into it, process those data (including multi-polygons with holes) and … Continue reading

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