Archive for April, 2011

Busy week

April 17, 2011

Short update about other activities after the rather technical post.

On Tuesday, we welcomed visitors from Norway to Kibera. A delegation from the Norwegian Minister of Local Government and Regional Development an UN-HABITAT was very interested in hearing about the activities of MapKibera.

Norwegian delegation from the Ministry of Local Government and Regional Development came visit MapKibera on March 12th, 2011. Courtesy of Mark Iliffe (CC-SA).

Norwegian delegation from the Ministry of Local Government and Regional Development came visit MapKibera on March 12th, 2011. Photo by Mark Iliffe (CC-SA).

On Friday, we completed the survey for water and sanitation in the pilot area of Mathare, that is villages No 10, Mashimoni, Mabatini. All open drains, toilets and open defecation areas have been added to OSM. We have two weeks to produce the report detailing the situation. We will also hold some training sessions and an evaluation of the mappers of Mathare. They’ve learned a lot in the last four months, now is a good time to check on their skills to better move on. As in Kibera, we will probably issue some kind of certificate.
By the way, I finally uploaded some photos of Mathare to picasa. Not well sorted, but I hope that give you an idea.

This week, Mark Iliffe honoured us with presence before heading to Lake Nakuru to work on flamingos. Funny coincidence, he was an exchange student in Nancy, France, my home town. Small world!

Load an OSM map onto a GPS device with a Mac

April 16, 2011

When our new flatmate asked me if I could help her to install an Openstreemap map of the Central African Republic on her recently acquired hand-held device, I replied “Sure! I only take a couple of minutes.” with great confidence. I’ve been generating my own garmin map from geofabrik’s extract of the whole continent and have a fresh one at hand. Little did I know about the actual situation. It took a lot more than a couple of minutes to find out the right tools. I hope to make it easier for other people with this blog post.

The first surprise came when I opened the battery compartment to extract the micro-SD card: Garmin Etrex Legend H does not support memory cards. It does have an internal memory of 24MB and a USB port though. The second funny news was the she had a Mac. It may not sound alarming at first, but getting your OSM data to that particular device using a Mac isn’t that straight forward. MapSource isn’t available on MacOS but Garmin provides two pieces of software: MapManager and MapInstall. In short, the complete chain is this:

  1. Get the OSM data of the area of interest
  2. Convert it to Garmin format
  3. Convert it to a Garmin format manageable by the Mac tools
  4. Install the map on your Mac
  5. Send the map to the GPS unit

and voilà! 🙂

Let’s take a closer look at the various steps:

1. Get OSM data.
Geofabrik provides extracts for continents, countries and even breaks down some countries into regions. However, few African countries have their own extracts. Since the Legend H has little memory, I used OSMembrane to cut data for CAR out of the africa.osm.bz2 dump with this membrane. I really like this tool, it’s a very nice and easy to use front-end to osmosis, a command line application for processing OSM data.

2. Convert to Garmin format
mkgmap is the tool for the job. It’s a command line application with many options (I’m not aware of a graphical front-end. UPDATE: there ARE some GUIs. I shall check them some day). In our case, the important argument is –tdbfile to explicitly generate the TDB file, which is needed by the next step. java -jar /home/seb/bin/mkgmap.jar –gmapsupp –tdbfile CAR.osm
This will generate a TDB file and some IMG files. If the GPS unit supported external storage, we could copy the gmapsupp.img to a folder “Garmin” on the memory card.

3. Convert to a Mac-manageable format.
Garmin offers a converter that runs only on windows. However Gmapibuilder (mac-installer) is multi-platform and will convert the previously generated maps to the gmapi format, which is manageable on MacOS. Open the TDB file generated at step 2 and convert.

4. Install the map on your Mac.
There are several pieces of software to manage maps on Mac. The first option I came across was MapInstall and MapManager whereas RoadTrip seems to be the MapSource equivalent to Mac. Use MapManager to install the gmapi map to your System. (I guess RoadTrip can do that too, but haven’t tried).

5. Send  the map to the GPS unit.
Launch MapInstall and you should see the map installed at step 4. Plug the GPS unit to your computer’s USB port and MapInstall will detect it. Select the piece(s) of maps you want to send and click Send. That’s it!

I’m looking at automating steps 1-3 and will publish the maps for Africa and various countries regularly.

“Do you feel safe out there?”

April 9, 2011

That’s a question I got asked a couple of times, so I thought it would be worth a post.
Yes, I felt safe while surveying drainage in Mathare. But that’s because I was together with local mappers. The local communities know our work and support us. However, that doesn’t mean it is safe. Looking at the place and date of this report, I was probably just around the corner when these guys were robbed at gunpoint. The same week, a car of gangsters chased by the police rushed through Juja road, firing in the air to make way. With the police executing suspects on the spot, these guys knew they had nothing to loose. Primož was working with mappers at our office located along Juja rd that day. I can’t find a proper report of the event, but I heard the five guys were found dead…

Seeing the level of poverty of these places, it is no surprise to see such a level of crime. We are concerned with security but consider the risks to be “low enough” to continue operating.

In other news, I took some photos of Mathare, which I will post when I get a chance to connect with adequate bandwidth. Tonight, I got to see “Soul Boy”, which was filmed in Kibera. Good movie as far as I can tell. I shall watch it again with subtitles since my kiswahili is far from fluent 😉