GIS for Mac OSX

Once, the only serious way to do much GIS work on your Mac was to use ArcGIS (or MapInfo) in a Windows virtual machine … but not anymore. QGIS Quantum GIS can now really compete with ArcGIS in terms of functionality and map creation. I miss a few things – proportional symbols for one – …

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QGIS on an Android tablet

Running QGIS on an android phone worked just fine – but running QGIS on an Android tablet is going to be a lot more useful, with a larger screen. I summarised the steps of installing QGIS on a Galaxy Advance (I9070) in a previous post, under Gingerbread (2.3.6); since then, there have been some issues …

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Using FieldPyculator for QGIS

Python power for your calculations It’s available in the QGIS plugin repository and thus installable with ‘Fetch Plugins’; source available on github. According to their webpage, FieldPyculator was developed by GIS-Lab. They have a Russian-language introduction to the plugin on their webpage, with an excellent Google translation. Using Use the toolbar button or the Plugins|FieldPyculator …

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QGIS with R: Working with the SEXTANTE plugin

I’ve tried to get QGIS and R playing together in the past, with only occasional success. The new SEXTANTE plugin for QGIS, which provides links into a number of applications including R, SAGA and GDAL, looks really promising. Getting it working on Mac OSX was a little tricky, as there is a (known) bug in the plugin that …

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Summarising QGIS project layers

With sometimes dozens of layers in a QGIS project, consolidating everything into one directory can be really handy (Plugins | QConsolidate). I’m finding this really useful when sending a project file to another device (like an Android tablet running QGIS) or to a colleague. Multiple layers with varying projections is a big performance killer in QGIS. …

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QGIS on Android phone: Installing

There is a more up-to-date version of this page detailing the installation on an Asus TF300T tablet here. I decided to try out QGIS on my Samsung Galaxy Advance – a little 4-inch screen, but why not? I’d run through the same process on an Asus TF300 tablet previously (much larger screen and more appropriate …

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Rotating a point grid in QGIS

Good ol’ GIS.stackexchange … I finally ended up posting a bounty of 50 reputation points for my rotation problem, and got an answer within a couple of hours! If you want to rotate a grid of points around (originX, originY) and degrees θ, enter the following values into the dialog (see image to the right): Scale …

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Troubleshooting install of QGIS in OSX

Yesterday afternoon I found I couldn’t run QGIS at all – it kept crashing on startup, whenever it got to the splash page “loading plugins” bit. I tried restarting without plugins running (/Applications/QGIS.app/Contents/MacOS/QGIS –noplugins) but it would still crash when I went to the “Manage Plugins …” menu option, so no chance of turning them …

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Using OpenStreetMap data in QGIS


OSM data for Arusha rendered in QGIS

One of the most commonly asked questions on the Tanzania GIS User’s group site is “where can I find good road data?” The data we had available generally 10 years ago was pretty poor – patchy and uneven coverage of the country, and poor metadata. OpenStreetMap.org now has a great deal of data available, contributed and edited by its users, and this can be used directly in QGIS.

 Click the image to the right to see an example … this is the OSM highway data downloaded as a shapefile from Cloudmade.com and rendered using the rule-based rendering for the layer.