On Friday 30 August I was sitting next to developer Bert Spaan when he put the finishing touch to his datavisualisation of all buildings of the Netherlands, according to their year of construction ("let's do this in English, CitySDK is an international project"). And I just had some time left to put the fact on Twitter.
The same evening, nrc.nl posted a news item (in 'the best of the web'), followed the next day by Dutch Cowboys. The item at NRC generated 40 reactions in a short time span. Most people like the map (Peter van der Ploeg on Twitter even says it is "the most beautiful site I've seen this month"). There were also remarks that certain data are incorrect. How come?
The data for this map are stemming from the 'Basisregistraties Adressen en Gebouwen' (BAG). Dutch municipalities are delivering the basic information, the Dutch register, 'the Kadaster', administrates the data. These are not always complete or up-to-date. Like the fact that all older buildings of Amsterdam have the same year of construction: 1005 (also de Waag). Luckily, people can report mistakes and omissions themselves at the Kadaster. By doing so, they can make it become a crowdsourced map!
Another issue being mentioned was 'getting lost' on the map, as it does not offer a switch to a normal map view. It's not ideal, but you can copy the coordinates from the address line and paste these in Google Maps (minus the last number, as it is the zoom factor). You can also click on a random building to see what municipality it belongs to (it shows up under 'Data'). Personally, I do prefer to have no further map details or labels. It gives you the opportunity (one could even make a game of it) to ask the question: where is this place?
The map shows The Netherlands from a whole new perspective. You can only view buildings, shaded according to their age, where blue is used from younger buildings (dating from 1960) and (deep) red for buildings from 1800 and before. It clearly presents the age distribution of our cities and also delivers many beautiful patterns. Who had thought that the new areas in Amersfoort would create such a nice view? (I will even use this for a leaflet about CitySDK, but on a white background).
And take the above picture (that I photoshopped a little to get a clear shape). Does it not resemble some kind of fish? It is indeed in a place abounding in water (in Sûdwest Fryslân).