Hi Schuyler
This is great, thank you.
For your questions on Somalia, there are several folks based in Nairobi we can
ask questions. I'll forward that now, cc you.
-Mikel
== Mikel Maron ==
+14152835207 @mikel s:mikelmaron
>________________________________
>From: Schuyler Erle <[email protected]>
>To: hot <[email protected]>
>Sent: Thursday, August 11, 2011 7:37 PM
>Subject: [HOT] Latest re: Increasing Somalia Coverage
>
>Hey gang,
>
>TL;DR: I am doing preliminary work on importing GNS and MapMappers roads into
>OSM. I will eventually need help. Someone who is intimately familiar with
>Somalian geography would be helpful right away.
>
>Last night I did some initial research towards importing data into OSM to
>improve our coverage in Somalia. I looked at three datasources:
>
>* UNHCR refugee locations
>* NGA GNS points of interest
>* MapMappers transport and hydrology layers
>
>(1) The UNHCR refugee location data is sadly unexciting. It's a KML file that
>consists mostly of UNHCR assets in Kenya and Ethiopia, with fewer than a
>couple dozen refugee locations, half of which are from 2007 or even earlier.
>None of the data is actually in Somalia. I don't see a reason not to import
>it, but it doesn't feel very high priority.
>
>(2) The NGA GNS data consists of 6,700 populated places, 4,200 assorted
>localities, 4,600 terrain features, 8,700 hydrographic features (including
>3,300 wadis), and 450 other points of interest. Somalia is one of the few
>places where I would seriously consider attempting this kind of import,
>because of the sparsity of the data. I expect to import only a fraction of the
>feature classes.
>
>Unfortunately, GNS imports have fallen out of favor in OSM, and all the code I
>can find to work with them is old and does very little for actually
>transforming the feature types into meaningful OSM tags. I haven't been able
>to find a good crosswalk between OSM tags and GNS feature codes, so I tried to
>do some statistical analysis of the distribution of OSM tags and previously
>imported GNS features in OSM but didn't come up with much. There are only 112
>feature codes used by GNS in Somalia, so I'll probably just break down and do
>the crosswalk by hand.
>
> http://iconocla.st/hot/so/dsgfreq.txt
>
>My plan for GNS is to do automated imports only of PoIs that are further than
>100m from anything currently in the database. The remainder I plan to split up
>into separate files (per Kate's recommendation) and import manually using JOSM.
>
>(3) The MadMappers road data appears to mostly have been traced from imagery
>from 2008 and a bit before. Here are the sources:
>
> SOURCE (String) = 200k topo maps (note: I think these are Russian - SDE)
> SOURCE2 (String) = Formosat January 2008
> SOURCE2 (String) = Landsat ETM+
> SOURCE2 (String) = Tracklog
>
>The feature types are interesting:
>
> fin_type (String) = Geological Trace/Track
> fin_type (String) = Major road
> fin_type (String) = Road
> fin_type (String) = Streets
> fin_type (String) = Track/Trail
>
>This Geological Trace/Track layer is curious, because it appears to contain a
>ton of straight lines that run at right angles through the middle of the
>desert:
>
> http://iconocla.st/hot/so/madmappers1.png (QGIS screenshot; the green lines
>are existing OSM roads)
>
>HELP: I'd like someone who actually knows something about the Somalian outback
>to reality-check us on this. I can see some of the depicted lines in the Bing
>imagery -- what the heck are they? They appear man-made. Are they actual roads
>(or trails)? Should we include them? Or should I just leave them out, to be on
>the safe side?
>
>We also get paving type:
>
> SURFACE (String) = Loose
> SURFACE (String) = Paved
>
>This is good, because there seem to be whole provinces in Somalia without a
>major paved road.
>
>We get some naming data, but not a ton.
>
>Again, per Kate's suggestion, I'd like to generate the .osm files and then
>parcel them out to volunteers for manual conflation, to avoid stomping on the
>work that's already there. If you look at the respective datasets for
>Mogadishu, you can see that both are woefully incomplete for a city of 2
>million people, but the overlap isn't complete, so there's useful work to be
>done manually:
>
> http://iconocla.st/hot/so/madmappers2.png
>
>Fortunately, the Bing imagery is *really* good there. So there's that.
>
>I strongly welcome any constructive advice that anyone has to offer.
>Otherwise, I'll let you know when I've got the data carved up and ready for
>people to look at. I'm hoping it'll be sometime over the coming weekend.
>
>SDE
>
>
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