Some notes on Map Kibera mapping

by: January 12th, 2010 comments: 3

Just yesterday, I imported the Map Kibera data into OpenStreetMap. I thought I’d take the opportunity to review how the data collection went in this entirely unique process, allude to a few of the mind-changing map features of Kibera that I’ve yet to fully comprehend, and provide some guidelines for further data clean up. I’ve been spending spare time over the last few weeks in Chicago working on the data, but realize this needs the help and energy of the entire community. If you’re interested to help, please get in touch.

In short, a pretty map geeky post! Divided into ways and nodes. This may excite you, or not ;)

Ways

Ways in Kibera encompass roads, paths, streams, sewer lines (sometimes hard to tell the difference between those two), village boundaries, the railroad line, walls, permanent buildings (there are many, yes), open grounds/playing fields, and markets. So far. An incredibly dense, informal area, there is a challenge to the uninitiated to simply decide what constitutes a public road in Kibera. As it turns out, Kibera has a complex structure well known to its residents. Collecting these ways required a combination of GPS surveying, which worked reasonably well even in a dense area of corrugated iron roofs, and satellite imagery, notes written on Walking Papers and in conversation. Both introduce their own accuracies and inaccuracies, so there’s also an element of artistry involved, as usual with cartography.

Tally of mapping day 2

These were initially traced by [User:Harry Wood|Harry Wood], from purchased DigitalGlobe satellite imagery collected in February 2009. Harry did a phenomenal job locating paths in this new terrain, which for the most part were later verified by GPS tracks. During and after the surveying phase, myself and other mappers traced from GPS tracklogs uploaded to the Map Kibera site, and from higher resolution GeoEye satellite imagery collected in July 2009 arranged by Lars Bromley of the [http://shr.aaas.org/geotech/ AAAS Geospatial Technologies and Human Rights program]. The GeoEye imagery was higher resolution (50cm, vs 60 cm for DG), brighter with a better color balance, but didn’t match the rectification of the February imagery, or of the GPS tracks. What followed was a series of tweaks and feedback between a very patient Lars and myself of re-rectifying the imagery; we finally got something which matched the GPS tracks more or less, and both learned that satellite imagery has shades of accuracy, subject to shakes in orbit, different angles of acquisition and lighting, that mean any correction in one direction results in a mistake in another region.

Besides the July imagery, the AAAS very generously donated purchase of another 5 satellite images from over the past three years in Kibera. We are very eager to explore the possibilities of automated and manual change detection and story telling using this resource; Kibera, like slums everywhere, changes rapidly, due to improvements by residents, resettlement by the government, acquisition and construction on private plots (mostly churches), and conflict on small and large scale. Imagery will help inform our understanding of these dynamics. For the moement, we have simply posted the layers to [http://aerial.maps.jsintl.org/layers/], and you are free to browse and select a slice of time. Particularly interesting are the Toi Market area, completely destroyed in the post-election violence and re-built in a new planned model, and the east side of Soweto East, the site of the first relocations and road construction. From these images is possible to date the Google imagery over Nairobi as pre-2006. For mappers, there are still a few permanent structures and walls that could use more tracing .. get in touch, and I can give you the JOSM or Potlatch settings for using the imagery.

Nearly all traced paths in OSM had GPS tracks associated, but not all, and in very dense areas, some artistic judgment was required to trace where a narrow path might really be going (these can of course be improved as more data is collected by other mappers). Road classification is still a challenge. In the formal villages, Olympic, Karanja, and Ayani, the roads are wide enough for vehicles, unpaved or in bad enough repair to qualify as unpaved, and very clearly evident in satellite and GPS, so highway=unclassfied or highway=residential. In the rest of Kibera, the situation is more interesting; for a place with no official centralized planning, there has definitely evolved a hierarchy of roads, branching fractal patterns intimately influenced by Kibera’s rugged topography. Some are wider, full of commerce, and obvious “main” roads; these have been tagged as highway=track. There are narrower paths, that are still very “public”, with significant commerce and foot traffic. These have been tagged as highway=footway. Also tagged as highway=footway are public paths through primarily residential areas. There are also even more narrow paths, nothing more than spaces between buildings, but still public; and paths that are practically private, through private plots. These all need differentiation, possibly though use of abutters=residential/commercial and private=yes tags. Complicating matters, the railway is the main thoroughfare of the area, so should be also indicated as a pedestrian area, and many of the creeks/sewers sometimes serve similar functions.

Three weeks of GPS tracks in Kibera

The village boundaries were initially roughly drawn from a [http://warper.geothings.net/maps/1640 map commissioned by Carolina for Kibera 7 years ago]. These were tweaked by mappers physically walking village boundaries when possible. Often these boundaries follow streams/sewers, or particular roads, and everyone is aware of precisely where they lie.

Nodes

Points of interest were the primary survey and editing activity of the Map Kibera mappers. They marked waypoints on the Garmin eTrex Legend HCx GPS, and made marks and notes on Walking Papers. They very quickly got hang of this, though there were particular subtleties, and sometimes not so subtleties, which we are still working to master.

One error that crept up occasionally were waypoints placed in an location different from where the mapper was standing. This occurs when the joystick on the GPS was moved, and quickly depressed, which the units interprets as intentionally placing a point in a different spot; vs holding the button down for 2 seconds to mark the present location. I have to say, that joystick is too clever, a persistent usability problem that has a steep body learning curve, especially for people who haven’t grown up with game controllers. Most of these errors were picked up immediately and resurveyed later; they were obviously misplaced, either in absurd locations or mappers in the wrong village, but certainly there is possibility that a few slipped through.

Each mapper definitely had their own style. In the intense density of Kibera, selecting which features are “important” is a judgment call and a matter of interest. There’s a baseline of water and sanitation features, clinics, religious and community buildings, etc. Some folks found m-pesa points important to collect, others not. Some folks picked every water collection point or water tank, even if private. Both of these things still need consistent, new tagging. Features like posho mills, battery charging stations .. entirely non-existent on any other maps. Is a movie theater in Kibera a movie theater, when it consists of a small dark room, a TV, and a DVD playing pirated movies? How to tag a witch doctor’s clinic, which these days are called “herbalists”? Most of the details on all these new features are simply in the NOTE or even name tag, all POI need some review.

Caution is needed. Even a name may not be a name. The use of a structure changes more rapidly than the availability of money to repaint a sign. So the sign might show a beauty parlor, but it’s currently used as a tailor, and everyone knows that and calls it by it’s “spoken name”. How can the map reflect both what residents already know, and what an outsider might need to know to navigate.

Some villages have much higher density of collection … as some places do have higher density of commerce, while others may be primarily residential, due to their placement peripherally to Kibera. Some are quite small, like Soweto West, so possible to comprehensively collect all. Others large places, like Makina, required additional surveyors in addition to the primary mapper, and it shows — occasionally I saw duplicate features. Capitalization never seemed to sink in with everyone … they just don’t use computers enough to care. Also, there was little care for which side of the “road” a feature sat on … something we can also improve with error checking days.

The density of features is really going to require moving to abutters and ways for many commercial areas. For web interfaces, we’ll need to separate things out into thematic, toggle-able layers. For print, we’re going to do a series of maps, atlas style, each focus on a different theme, with more narrative and photos.

So

Chickens, goats, dogs, movie theaters, hardware stores, pubs, kerosene, charging stations, butchers, trees, sewers, rocks, mud

mapkibera twitter

Mapper Diaries

by: November 25th, 2009 comments: 0

Mapper Diaries

Here are some excerpts from the short diary entries that mappers have made upon uploading and editing their data in OpenStreetMap over the past three weeks:

This was my first day to do mapping and the day was quite intresting. Being that it was my first time to use a GPS machine. In the morning we went for afieldwork using GPS and we cuptured alot of thinngs. In the afternoon we used paper walking. So its quite good that as days goes on i will be knowing alot concernin Kibera. THANKS
Posted by anekeya at Tue, 10 Nov 2009

The campaign against Kibera’s Isolation: Early on the morning of 9th nov I and my associates came together and joined the team of Mikel in the mission to map and put Kibera on line.
Posted by Gee at Tue, 10 Nov 2009

Great to have volunteered in this exercise. For sure, there are lots of new stuff to learn ranging from the kibera community response on the mapping exercise and the new enhanced technologies.
Posted by Marimba Fednance at Thu, 12 Nov 2009

i enjoy mapping my ghetto, it is adventure
Posted by kevin at Mon, 16 Nov 2009

my fellow friends it has been a very nice experience to learn new things as a team and the challenges, i will urge to continue with same spirit please keep the fire burning. Guys we are the people we must be proud of Kibera and upgrade is part of our country Kenya
BRAVO
Posted by millicent at Mon, 16 Nov 2009

With time the marking got easier and interesting in Katwekera.
Posted by Gee at Fri, 20 Nov 2009

On 19th i mapped Makina. I realised that Makina is a wide village.
Posted by anekeya at Fri, 20 Nov 2009 08

mapping Lindi on this day was very cumbersome considering the fact that the rain had caused a lot of mud making it difficult to explore far flung areas of Lindi.
Posted by leonard kwaks at Fri, 20 Nov 2009

I got to learn more about the area especially the challenges facing the residents
Posted by lucy at Tue, 24 Nov 2009

Hello, guys it has a very nice experience to have new faces in carrying out Kibera map where we are trying to collect the hidden features and bring them into light. These will also help people of Kibera and country wide to access and know what we really have, positive changes and reality of Kibera. Thanx.
Posted by millicent at Tue, 24 Nov 2009

Getting to Nairobi

by: October 25th, 2009 comments: 0

Only two days late, not bad. Loss of power, rapid descent and no comment from the cockpit, it certainly didn’t feel like a normal manuever. Our flight from DC to Amsterdam lost one engine, turned around over Canada in a set of new-feeling one-engined manuevers, for a landing in Bangor, Maine. Bangor was ready with the unnecessary fire trucks, but not ready for much else. On the ground, sequestered in a wing of the tiny airport, the herd control techniques of the KLM flight crew soon went unscripted and chaotic, and they quickly went for their favorite flight placating technique — food! — we ate the breakfast we should had been eating flying over Ireland the next day.

What followed was a terribly interesting exercise in information mismanagement and sociology, somewhat resembling the tv show Lost. The leading mismanagement theory seems to be that the less uncertain information given to a crowd, the better .. I of course believe that open questions and potential answers should be open, and information can only help. Are they going to repair the engine here? Is a new jet being flown in? Where are we sleeping? Do you know what you’re doing? Unexpectedly, in the midst of trying to surmise all this, I made a contact with an education specialist from USAID, who lamented that a recent survey of Kenyan schools totally overlooked schools based within informal settlements .. we should be able to fix that.

The first bad sign of the plan was 250 folks descending an escalator to a tiny landing on the floor below, with much hollaring preventing impactful disaster. Herded onto buses, off into the Bangor night, we arrived at the Hollywood Casino Hotel, and to a single night attendant who saw no need to modify the normal checkin routine for 80 grumpy guests, a procedure which lasted til 2am. His instructions were to fill available rooms, maybe 53, until the hotel was full and then call the airline to pick up the remainder for transport to another hotel. An inhumane plan, so I decided to count, democratically filling the incompetency of a flight crew on the ground. So down the line, counting who was planning to share, or willing to share with a new friend “for the cause”. This quickly got personal “my wife and I will share one room, but need two queen beds” was the response of one Indian gentleman.

My ideals of openness are often tested. Some self-reliant folks at the back of the line had called the airport hotel, steps away from where we boarded the bus, and found they held 30 rooms for KLM and there was no line. We were uncertain about if we qualified for this, perhaps only first class and the crew, but decided to taxi and go for it. The test to myself .. how should this information be shared with the restless crowd of the Hollywood Casino Hotel? I decided a general announcement of rumored relief could cause a riot, so shared just to a couple individual points, and taxied off to what was an easy, free night at the Bangor Airport Sheraton. Had I become the authoritative judge of information sharing?

The next day, clans formed in the airport waiting areas (the restaurant featured an awesome lobster roll sandwich actually), and rumors swirled. A pretty reliable message of a late evening replacement plane arrival from a Sheraton co-conspirator, was quickly squashed as rumor by the lead flight attendant — “the captain has not yet decided with Amsterdam” — was eventually shown an attempt at authoritarian information control. That’s exactly what happened, and I would’ve known that a plane was due anyhow if I had checked Flight Aware for the newly created route of Amsterdam to Bangor (also soon found the record of our original flight, and the distress call). Twitter also played a roll in undermining official information flows, with my late night play by play, getting the attention of a local newscaster, who sent out a team to report, and broadcast. They tried to find me, but came apon another very competent eyewitness with a beard, Matthew Briggs.

We were off to explore Bangor, home of the largest runway in the US, former main refueling jump for trans-Atlantic flights, former home of the largest radar array in the world (to see those Russian nukes raining down), one of the most industrious lumber towns of the 19th century, AND home to Stephen King. I learned all this on the most lovingly crafter Wikipedia article on Bangor. The town was beautiful in a way too few small American towns have retained.

We also got to explore Amsterdam, in only a sleepless haze, after missing yet another connection and having to argue for a cheap hotel room courtesy KLM (Boo KLM!). We visited the sights .. the red light district, Residence le Coin hotel where the OSI scholarship crew stayed for State of the Map, and the Reijksmuseum. From there, it was pretty uneventful and normal to our landing in the perfect temperature evening of Nairobi.