Adding KML overlays to Google Mapmaker

Editing maps in Google Mapmaker has proved to be a bit of a challenge when there isn’t a good satellite image for the area. OpenStreetMap, by comparison, has a number of editing tools that let you directly use GPS data on-screen to edit roads (but it seems to be much less straightforward to get satellite …

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Getting Google Docs data into R

This was a tortuous path to success … seems like Google has changed the way GDocs are accessed several times over the past couple of years, including https by default which meant that normal read.csv(url) functions didn’t work. To get the mobile internet spreadsheet I wrote up for TZCRC: Opened the spreadsheet in Google Docs, …

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Spatialite and rasterlite on OSX

Spatialite and rasterlite are libraries for SQLite, a small database system that works from single files. SQLite databases are very easy to administer and share, and are read natively by QGIS without any need for configuring drivers and passwords! These two libraries let you add spatial capabilities to SQLite. If you’re already using QGIS (and …

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Homebrew on OSX – easy installation of UNIX/Linux tools

“the easiest and most flexible way to install the UNIX tools Apple didn’t include with OS X.“ … and they’re right! Homebrew can help you to install a whole range of great UNIX / LINUX tools (wget for one), in single steps; an alternative is MacPorts, but I have abandoned it in favour of Homebrew as …

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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. 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 and rendered using the rule-based rendering for the layer.