Entries tagged with haiti

Part of the OSM Haiti response has been to pick over fresh satellite images and mark stuff. Half of that is map-tarting, the other half is looking for interesting places: collapsed buildings and bridges, landslides, campsites. This phase is more or less done now, with the relief agencies rolling that data into the other crisis sources and using it as they will.

I've been staring into sat photos (DigitalGlobe and GeoEye have been utter stars in making their data widely) available all week, and wondering if the process could be automated. Collapsed buildings visible from space go into two patterns, it seems: the roof falls in leaving a tic-tac-toe grid of walls, or the whole thing turns to rubble (many buildings have pancaked instead, with the walls failing and the roof falling intact: these aren't easily visible from directly above). Campsites are erratic splats of tent colours in otherwise plain areas. So some rules could be drawn up:

If in a block of edge-detected buildings there is an area of high noise and it's not green, it's probably rubble.
If edge-detection finds a cluster of boxes about a factor or two smaller than their neighbours, it's probably the rooms inside a house.
If in an area of otherwise plain detail there are spots of noise in telltale colours - tarp blue and tent orange, particularly - it's likely to be a campsite. This is especially true if the site is already geotagged as a park, playing field, car-park, etc (ie an open flat space).

It would need higher resolution imagery, but not by much.

I must confess, there's a part of me that worried about the prurience of scrambling to update a map of a disaster zone. That's what I and scads of others have been doing on OpenStreetMap since the Haiti quake struck. On its own, as just another map, that might be true, but OSM's not on its own like that.

It took about twelve hours to get the coverage in Port-au-Prince (PAP) up to best in breed, and at the same time the amazing flexibility of wikis was coming into play. GeoEye provided a Bourne-style high-res satellite image of the day after the quake; it was deployed as a traceable background layer. A tagging schema was agreed in IRC and mailing lists and wikispace for refugee camps, damaged buildings and blocked roads; the OSM deep nerds set regular extracts running so fresh maps are always available for agency GIS, routing, satnav and so on. In parallel, the map was amped up in detail and at the same time the disaster-specific information was sourced, implemented, distributed. "Please tag camps and graveyards". Grim.

It could still be prurience: zooming in to see, is that rubble or a crowd? tents or tin roofs? collapsed buildings or just shanty neighbourhoods? - it has the fun of a resource-management computer game -- until one of the search and rescue teams said thanks for the Garmin extract. And then the kid on the news is shown camped in a football pitch you spotted earlier. Then it all gets a little bit real.

Medicin sans Frontiers will be in with an inflatable hospital soon, and the USS Carl Vinson just arrived with the USNS Comfort en route. They'll get marked up once they lay anchor. The system is insanely agile, the wiki mantra "assume good faith" paying off in spades.

Rubble and Tents

Haiti and disaster mapping