Technomancy

I wrote previously about my difficulties in creating a navit file for the whole OpenStreetMap planet file.

However I discovered today that the Navit project provides an dump of the OSM planet file on their website!

Navit formatted OSM planet file

When I was in Kenya in July 2008 with Camara teaching people how to use Ubuntu Linux, I brought a hard drive mirror of apt with me. Over in Africa bandwidth is slow and expensive, I was able to use this apt mirror to install new software easily over in Kenya. I gave a talk at OSSBarCamp about Using Free Culture in an Internet Free World.

I'm doing it again. A friend of mine in Kenya asked for a new harddrive. So what would you put on a harddrive going to Kenya?

I asked on the Ubuntu NGO mailing list, and got some great responses, from Ubuntu Screencasts, printer drivers, and wikipedia dumps. What else in the free culture world is there?

This post also appeared on the Ubuntu NGO Blog

In September 2009 I did a talk at OSSBarCamp in Dublin, Ireland entitled "Using Free Culture in an Internet Free World". It was about my experiences using Free Culture / FLOSS / Linux in Africa where the internet access is very bad. Free Culture (e.g.: Wikipedia) and Linux can help you get around this. Find out more by watching the video.

blip.tv page | Direct download link to the video (534MB)

The video is copyrighted but released under a Creative Commons Licence, CC-BY-SA

In my quest for creating an offline atlas of the world that can given away for free, I've been trying to use navit, an open source satnav system. They have a very compact file format for OpenStreetMap files. I downloaded the latest OpenStreetMap planet dump, planet-090701.osm.bz2, (MD5 checksum: 9133f22e4d09b73f86e1f4d68539879d) and ran osm2navit on it. As soon as I started to run it, I got thousands and thousands of errors like this:

WARNING: unknown tag in   <changeset id="1696734" created_at="2009-07-01T00:10:10Z" closed_at="2009-07-01T00:10:14Z" open="false" min_lon="9.5064856" min_lat="52.7634646" max_lon="9.6230595" max_lat="52.8229376"  user="mfi" uid="58950">
WARNING: unknown tag in   </changeset>

However I let it run, and after about 2 hours, osm2navit crashed and I got the following error:

PROGRESS1: Processed 378663035 nodes (14343033 out) 29925604 ways 140057 relations 0 tiles
5 slices
flush_nodes 1
slice 1 of 5
reading -4294967297 bytes from coords.tmp at 4294967296
osm2navit: osm2navit.c:1642: load_buffer: Assertion `b->base != ((void *)0)' failed.
Aborted

And that's where I am now. I think it might be because OpenStreetMap have moved to a new file and API format, 0.6, and perhaps osm2navit hasn't been updated.

I'm trying to find a way to show OpenStreetMap data offline, so it can be used in places with little or no internet. Navit is a open source car navigation system. It runs fine as a desktop application. And they have created a binary file format for storing OpenStreetMap data. It has an advantage of creating small file sizes. This might mean it'd be possible to store the whole OpenStreetMap planet file on one CD. The XML file compressed is 6.7GB, which is too large to fit on any practical disk. I'm downloading the OpenStreetMap planet file and will convert it to Navit format to see how much space it takes.

The Navit interface is OK but isn't great. It's good if you want to look at street level, but I envision an Offline OpenStreetMap being used in an education context, which means looking at it at a country or county level. Someone on #navit suggested using Navit's binary file format and plugging it into a nicer rendering engine.