HOT Contact / Tropical Cyclone Molave

Greetings OSM Thailand,

Forgive the delayed introduction, with the many Cyclones we’ve had this year I have been wanting to make contact and with Cyclone Molave leaving the Philippines (where I’m currently based) and headed your way, now is as good a time as any.

I hear your community’s frustration with organized editing happening without the discussion, so first - it is my job at the Humanitarian OpenStreetMap Team (HOT) to make sure this communication happens in regards to disaster mapping. Hence why I’m contacting you now instead of after the fact once we have a request to map Thailand (which is actually acceptable in the organized editing guidelines, but we can do better then that).

So as my first interaction on your forum - is this the preferred way to converse if/when there is a disaster in Thailand that HOT is (preparing to respond/responding) to? It looked to be the more active place listed in the OSM Community index.

Second - don’t hesitate to reach out to us if there is a disaster that you need help with, an email to will kick-start the conversation.

And last, for those who do not know about HOT well, we organize a lot of the ‘humanitarian mapping’ that you see in and around OpenStreetMap. From remote mapping to get basemaps for response and aid organizations, to field mapping and training on mobile data collection, most famously our technology and innovation team creating solutions like the OSM Tasking Manager and OpenAerialMap among others, and our community and partnership engagements such as Missing Maps, the Microgrant programs and so much more. All in attempt to empower organizations, and more importantly local mappers.

We’ve made our mistakes as well, so that is partly why I’m coming here now; if Cyclone Molave causes havoc in Thailand, we don’t want to cause a swarm of people haphazardly adding data to the map. We want to coordinate with locals who know best what is needed and whether or not that is doable by the crowd.

I hope this is just a false alarm and Molave only brings you some rain, but do reach out if HOT can help coordinate an organized mapping response that puts useful geospatial data into the hands of first responders, aid organizations, and the local communities finding their way to recovery.

Happy Mapping!

Russell Deffner
Disaster Response Coordinator
Humanitarian OpenStreetMap Team

Hello Russ,

thank you for proactively reaching out. You got it right: We face a lot of frustration with regards to organized mapping.

We highly appreciate support in improving OpenStreetMap in Thailand. As we are very proud of the very high quality standard we achieved in Thailand in comparison to our competition, you surely understand why we push so hard to keep up this quality.

So the key point in any organized mapping activity has to be quality control. And to put quality over quantity in regards of mapping.

It does not help to draw 1,000 oddly shaped polygons and label them as buildings which have nothing in common with the reality. There are easier ways to get approximations to population density. And if you would decide that for whatever reason these rough outlines would do it, then store it in a separate temporary database independent from OSM. In Thailand the buildings have regular orthogonal shapes like in other parts of the world.

We notices that often people participating in organized editing are using the tooling wrong or choose plainly wrong labels for their mapping. Sometimes they add “markings” on the map to see “their” area on the map.

You, as an organizer, have to cover such aspects. You have to provide proper introduction to the newly brought in mappers. You have to provide enough experienced mapper capacity to timely review their edits and improve the quality in the beginning, not after they invested hundreds of hours with a result better deleted right away.

I know that HOT has training materials. So you have to make sure it reaches the people. You also have to take an active role in reviewing first edits and not simply saying that iD has set the review request label and not it is no longer your problem who is actually doing these review.

In case you want to tag something special it is best to clarify beforehand the established tagging scheme in case it enteres the not so well defined areas of the OSM ecosystem.

To start early with such a discussion: What kind of features would you foresee as a mapping priority in case the cyclone strikes? Road and railway network is quite complete on the major level. Do you intend to add specific tags for marking flooded areas or destroyed bridges/unpassable roads? As it was observed in the 2011 flooding, armed forces are quick in helping the worst affected areas. And certainly people are prepared better since that time. When mapping from remote on aerial imager which is then quickly outdated a few weeks later: how would be the plan to update the map after repairs which certainly happen shortly after?
There must be a sustainable plan. Otherwise a temporary secondary database which overlays OSM as a basemap would be a better solution.


Hi Stephan,

Each disaster is unique, so I can’t really say what is foreseen with Cyclone Molave. A complete pre-disaster basemap (buildings, roads, waterways) are typically most broadly useful for disaster response. HOT typically does not do post-disaster mapping, at least not any damage assessment as of yet because, as you point out, there is no generally accepted way to do it.

Keep in touch if you know of any first responders, aid agencies, or local communities using OSM and need mapping help!