The Netherlands is starting to look really great in OpenStreetMap. This is due only in part to the tireless efforts of the Dutch Mappers – who are not to be deterred by the cold, rain, hail and winds of the Dutch fall season. Data imports have played a very important role in the state of the map in the Low Countries. As early as 2007, AND released its complete road network for The Netherlands to OpenStreetMap, and was imported in July and August of that year.
More recently, a comprehensive high resolution buildings and land use dataset was released for public use in a license compatible with OpenStreetMap. Import of this 3DShapes data set commenced almost immediately, starting with building footprints. Land use is ongoing – if you take a look at the map now, it is easy to distinguish the regions that have seen land use import love from those who haven’t yet.
These imports make the map look beautiful and contribute enormously to the richness and completeness of the data. In the Dutch OpenStreetMap community, there has been little if any resistance to the large scale data imports. What helps this run smoothly is that the imports are done by dedicated OpenStreetMappers who take every precaution to make sure no arduous manual edits based on ground surveying are overwritten without consent.
Apart from a visually stunning map, there are more arguments in favor of these large scale imports. A map that already contains information for your local area is less daunting to start working on than a map that is empty and void, so data imports may help lower the barrier to entry for new contributors. A map that looks complete is also more attractive for potential users, and thus may encourage professional use of of OpenStreetmap data.
Still, I feel ambiguous about the large scale imports that we are seeing in the Netherlands. I support all the arguments I mentioned in favor of them strongly, but there’s also some important drawbacks that I’d like to point out here.
The most important issue I see has to do with data aging and pseudo-information. As it is, the data being imported is a few years old. It comes from a source that would update it by ground surveying every few years to keep it up-to-date, but as yet it is unclear if newer versions of the dataset will also be released under a compatible license. Even if it will be, a re-import will be a hard thing to do. The community will go ahead and update imported the land use data in OpenStreetMap, acquiring its own community dynamic. That will be difficult if not impossible to retain in a subsequent import of a new version of the source data. I’m therefore going to assume that both the AND and the 3DShapes imports will remain one-time efforts.
Given the singular character of the large scale data imports, it is upon the OpenStreetMap community to keep it up-to-date after the initial import effort. In some areas, this will be done diligently by a dense network of active OpenStreetMappers. But community activity is not spread evenly over the Netherlands In others, community activity is sparse and the data just sits there, turning stale slowly. This raises the question which is better: no data at all, or one-time imported data that is slowly turning stale?
Stale data represents pseudo-information, in my opinion. As long as the data is more or less static, it is not such a big deal. Land use is more static than the road network, but it still changes over time. On average, more than 15% or the road network sees some kind of change every year according to some. Even if it’s half that, road network information requires a lot of community love to keep it from going stale fast. I realized this soon after the initial AND import, and requested a layer in the awesome Geofabrik OSM Inspektor tool that would reveal which parts of the road network in the Netherlands had actually seen any community updates since the imports. On higher zoom levels, this layer reveals that some cities have seen almost no updates in the last three years! Assuming that the data was around two years old at the time of import, this means that even in major towns and cities, most of the road data is five years old by now. For use in a background map, that may be just fine, but for more data-critical uses such as routing, five year old data has little value. How much would you pay for a satnav device with data that old on it?
Another more fundamental issue has to do with OpenStreetMap as a community effort. Looking at the OpenStreetMap of Amsterdam, I still feel a sense of pride. I made a significant contribution to this map. I know most of the other OpenStreetMap mappers here. We get together now and then to discuss the local state of the map. On the scale of the Netherlands, looking at the map I do not feel that sense of pride anymore. The map does not feel like a community effort, it feels more like a repository for open data. The map looks great but it looks cold – the quality looks about the same across the country, but that obscures the huge differences in community activity, which in some regions is all but nonexistant. I doubt that the current situation, the map looking the way it does and the tools availble for editing being what they are, will inspire people in those regions to join and start contributing.
Arguments for and against large-scale imports like we are seeing happening in the Netherlands are both strong. OpenStreetMap largely ignited the open geodata movement, and I think it’s awesome that we’re now seeing more geodata becoming open, and OpenStreetMap becoming a showcase and repository for that open data. I do believe that the community can, in some places and to some extent, benefit from these infusions of open data, improve it and keep it up-to-date. One of the pillars of a community however is a common goal; the sense of building something together. As that common goal fades out of focus, it takes much more than a casual glance on the Dutch OpenStreetMap to see the community effort.