Notes for #NepalQuake Mapping Sessions @RyersonU Geography

This is an impromptu collection of information to support a series of meetings of Ryerson students, faculty, and alumni of the Department of Geography and Environmental Studies with getting started with OpenStreetMap (OSM) improvements for Nepal. As part of the international OSM community’s response, contributions may help rescuers and first-responders to locate victims of the devastating earthquake.

Note that I moved the reports on our mapping sessions out into a separate post at

Information from local mappers: Kathmandu Living Labs (KLL), KLL’s crowdmap for reports on the situation on the ground:

Humanitarian OpenStreetMap Team (HOT):,

Guides on how to get started with mapping for Nepal:

Communications among HOT contributors worldwide: Also check @hotosm and #hotosm on Twitter.

Things to consider when mapping:

  • When you start editing, you are locking “your” area (tile) – make sure you tag along, save your edits when you are done, provide a comment on the status of the map for the area, and unlock the tile.
  • Please focus on “white” tiles – see a discussion among HOT members on the benefits and drawbacks of including inexperienced mappers in the emergency situation, (via @clkao)
  • In the meantime (May 3rd), some HOT tasks have been designated for “more experienced mappers” and few unmapped areas are left in other tasks; you can however also verify completed tiles or participate in tasks marked as “2nd pass” in order to improve on previous mapping.
  • Don’t use any non-OSM/non-HOT online or offline datasets or services (e.g. Google Maps), since their information cannot be redistributed under the OSM license
  • Don’t over-estimate highway width and capacity, consider all options (including unknown road, track, path) described at Here is a discussion of the options, extracted from the above-linked IRC (check for newer discussions on IRC or HOT email list):

11:23:18 <ivansanchez> CGI958: If you don’t know the classification, it’s OK to tag them as highway=track for dirt roads, and highway=road for paved roads

11:26:06 <SK53> ivansanchez: highway=road is not that useful as it will not be used for routers, so I would chose unclassified or track

12:31:12 <cfbolz> So track is always preferable, if you don’t have precise info?
12:32:11 <cfbolz> Note that the task instructions directly contradict this at the moment: “highway=road Roads traced from satellite imagery for which a classification has not been determined yet. This is a temporary tag indicating further ground survey work is required.”

Another example of a discussion of this issue:

  • Map only things that are there, not those that may/could be there. Example: Don’t map a helipad object if you spot an open area that could be used for helicopter landing, create a polygon with landuse=grass instead (thanks to IRC posters SK53 and AndrewBuck).
  • Buildings as point features vs. residential areas (polygons): To expedite mapping, use landuse=residential, see IRC discussion below.
    More about mapping buildings:
  • Be aware that your edits on OSM are immediately “live” (after saving) and become part of the one and only OSM dataset. In addition, your work can be seen by anyone and may be analyzed in conjunction with your user name and locations (and thus potentially with your personal identity)

Note that I am a geographer (sort of) and GIScientist, but not an OpenStreetMap expert (yet). If you have additions or corrections to the above, let me know!