Beer and maps

Text: Katri Isotalo

Charity without any commitment, game-like activities and meeting like-minded people – there are many motives for voluntary mapping.

Tuopillinen olutta.

I have walked with old people outdoors, but I’m not familiar with doing mapping for charity. Well, I’m not familiar with mapping in general. However, I boldly step inside a pub in Helsinki with my laptop where a HOT Beer and Maps event is about to start. It doesn’t mean that they serve hot beer – HOT stands for Humanitarian OpenStreetMap Team.

About a dozen map professionals or students and a couple of newcomers like me are present. One of the new faces is a Nepalese student of environmental engineering and the other is an active user of OpenStreetMap (OSM) data.

First, I log in to OSM (, the Wikipedia of maps. Next, I’m instructed to go back to It offers areas from different parts of the world for which maps are needed. The Tasking Manager tool makes sure that only one person is mapping one area at a time. Our group selects an area close to Can Tho, a town in Vietnam. It is not a disaster area, but it needs to prepare for the flooding Mekong river. Eduardo Gonzales, who recently returned from Vietnam where he led a forest information project of the Ministry for Foreign Affairs, speaks about the area.

I select one easy-looking grid from the target area on my screen, after which I can access a Bing satellite image. It shows only a few buildings and irrigation ducts. Someone has already mapped a larger channel that travels across the grid. Towns with their many buildings, as well as special terrains, should be left for more experienced users.

There are various editors to use. I decide to use iD. It is intended for beginners, but I still manage to make a big error: the irrigation duct which I’m mapping is shown as a dashed line, not as a continuous network. Luckily, Vuokko Heikinheimo, who is sitting next to me, sees this, and helps me to correct my error. Properties must also be defined for mapped areas. It is easy to select a classification for an irrigation duct from the menus. However, I’ve heard that the classification of African roads, for example, is not easy for Finnish users.

Routes for vaccination campaigns and landings sites for helicopters

Around the world, HOT events among OSM users started some ten years ago. Voluntary mapping became a busy activity in 2010 when volunteers aimed to help rescuers after an earthquake in Haiti. The mapping needs of voluntary associations are coordinated, for example, through the Missing Maps project. HOT is one of its founding members.

In Finland, general interest towards humanitarian mapping increased after an earthquake in Nepal in 2015, and regular HOT events have been held in Helsinki since autumn 2015. When the name of voluntary Mapathon meetings was changed from OSM coffee events to OSM beer events, the number of participants increased directly. In addition to voluntary meetings on Thursdays, the HOTOSM group has held larger and more organised Mapathons with the Red Cross, among others.

When a real disaster strikes, volunteers from all over the world map the area in just a few hours. This is why HOT events, held in Helsinki every two weeks, focus on less urgent areas. In principle, anyone can propose an area to be mapped using the Tasking Manager tool. However, these areas are often proposed by the Red Cross, Doctors without Borders or any other local humanitarian organisation. The mapping request indicates what areas should particularly be mapped. If there is a flood, data is needed about rivers and inhabited areas, whereas roads and villages need to be mapped for vaccination campaigns. In disaster areas, data about suitable landing sites for helicopters is also valuable.

Crowdsourcing is a productive source

In one hour, I’m able to map two irrigation ducts and two buildings. What I learned is that the laptop mouse is not a good tool. However, mapping does not require any special equipment or a gaming computer. But what if mapped areas are classified incorrectly? What if a garden shed is classified as a residential building, or vice versa?

To my relief, I’m told that a local or at least a more experienced cartographer always validates the work of remote users. Grids to be mapped have been colour-coded to indicate whether the particular area is unmapped, mapped and/or validated.

Even though a couple of irrigation ducts seem like a modest result, Vuokko Heikinheimo consoles me by saying that now it’s done and no-one else needs to do it. She says that she started by spending 20 hours mapping roads and inhabited areas in Mozambique for a cholera vaccination campaign. She realised that 20 people would have been able to do the same work in one hour!

An alternative for Facebook

Everyone can do this at home. However, the participants in the HOT event agree that it’s more fun working together. You can always ask for help from the person sitting next to you, and you can get to know other like-minded people. “This is a good way to be useful without being overly committed”, says Pauliina Jalonen, describing her hobby. “Most importantly, this makes me feel better than spending a couple of hours on Facebook”, Vuokko Heikinheimo continues.

Erno Mäkinen also believes in the power of competition. The statistics of each mapped area shows how many grids or square kilometres each user has mapped. The Missing Maps site even includes a leaderboard that lists the most active users. However, just mapping simple field areas isn’t enough; the content of each grid also matters.

If the available space doesn’t limit the number of participants, HOT events are open to all, in Finland and everywhere else. Events in Helsinki are advertised on Facebook. The HOTOSM group encourages everyone to launch mapping events in other parts of Finland and helps everyone interested to get started.


Article in pdf >> 
Positio 2/2019 table of contents >>