WorldWideHelp and ShelterFinder are stepping up in response to the Indonesian Earthquake. I’m engaging, trying to free up the flow of satellite imagery, village/hospital/airport location dbs, mapping apis, photos, textual reports, etc into a fluid coherent shape, meaning GeoRSS and KML.
First pass, I took locations listed in the ShelterFinder wiki, and manually created a quick GeoRSS file, and loaded into a Yahoo Map. Of the big 3, Yahoo currently has the best map coverage of Indonesia. From this, I experimented in mapufacture, layering weather and disaster alerts with these locations in the mapufacture JavaQuake.
Later I heard about satellite imagery released by the German Center for Satellite Based Crisis Information, taken post quake with damage assessment overlays. This would be very useful in Google Earth. Helpfully, these were posted with georeferencing world files. These images were projected in some form of UTM, while Google Earth expects image overlays unprojected with lat/long extents. The projection itself was not specified in the world file, but directly in text with the image as “UTM Zone 49 S”. I hopped on irc #geo, and was quickly aided by Tyler Mitchell, Schuyler Erle, and Chris Schmidt. After some experimenting, the method hit on was to use gdalwarp to convert each jpg/worldfile into an unprojected GeoTiff, and then gdal_translate to produce a jpeg compatible with Google Earth, along with another worldfile listing in lat/long. Here’s the geek…
gdalwarp -s_srs '+proj=utm +zone=49 +datum=WGS84 +south' -t_srs 'EPSG:4326' bantul_high_1.jpg bantul_high_1.tif
gdal_translate -outsize 50% 50% -of JPEG -co WORLDFILE=YES bantul_high_1.tif bantul_high_1_50.jpg
Thanks to Chris Schmidt for doing the heavy lifting here. I took the results, calculated the extents, and produced a KMZ of remote assessment of Indonesian Quake Damage.
Still a year or so into map mashup hype, I’m surprised this wasn’t easier, and that the original publishers didn’t think of producing KML for their imagery. And there’s loads of other sources producing images and data that could be useful for relief efforts, and put into KML etc. There’s still a ways to go to design geodata for sharability.
A side note, at XTech the other week, Anselm Hook and I were discussing methods to specifiy image overlays in GeoRSS, and I think we found something that could be useful. An image can be specified using MediaRSS, and its extents specified with a GeoRSS Box Geometry, with a relationshiptag of something like “image-extent”. Mappers and visualizers would treat this the same as a KML GroundOverlay. Why not just stick with KML? Cause GeoRSS already has wider support, and greater potential for support and aggregation, and there are tools for translating GeoRSS into KML, if not the possibility for native support at some point.