Sanderd17's Diary

Recent diary entries

New Open Data for Flanders

Posted by Sanderd17 on 4 December 2015 in English (English).

Today, the GRB database was opened to the public on the Flemish Open Data license (which is compatible to ODBL).

The GRB is a massive dataset, it contains many different types of data:

  • Administrative parcels
  • Building outlines
  • Building-attachments (stairs, roofs, …)
  • Man-made objects: bridges, chimneys, water towers,
  • landuse: railway-areas, highway-areas, residential, natural, recreational, …
  • road-related features: bus shelters, bicycle parkings, curbs, guardrails, poles, manholes, …
  • highway and waterway areas and center lines and even more

Of course, it will be a massive job to figure out how the relation to OSM is, and if the features can be imported in some way. But I think we’ll be able to handle this.

manhole cover manhole covers on a map

Location: 1850, Flemish Brabant, 1850, Belgium

Address evolution in Belgium

Posted by Sanderd17 on 5 February 2015 in English (English).

As there has been an Address import in the Brussels region, and the Flemish Agiv also opened a database with address positions (not good enough to import directly, so we agreed to draw the buildings from aerial imagery while adding addresses, that way we at least check consistency of addresses). In Flanders, it’s a slow import that started around the end of 2014.

So I wondered what evolutions were visible lately. If it was possible to see where people were editing. Stuff like that.

First I investigated the total number of addresses per province. Brussels capital region doesn’t have any provinces, nor does it belong to a province (although it’s completely enclosed by one). But Brussels is included next to the provinces, just to cover Belgium completely.


Here you clearly see that Brussels has many addresses mapped. Most likely due to the import. But between other provinces, there are also major differences. Oost-Vlaanderen and Vlaams-Brabant are both part of Flanders, they have the same resources, but there’s a major difference. The population also doesn’t seem to matter, as Oost-Vlaanderen has almost 1.5 million inhabitants, and Vlaams-Brabant has just 1.1 million.

Then I wanted to compare addresses with their data types, to see if nobody just imported nodes from Agiv without drawing the buildings. Nodes as addresses are not forbidden (f.e. on an entrance), but the clear majority should be on buildings.

Comparison of data types

Ok, this looks good. Most addresses in Flanders are on buildings. Ratios seem rather constant. There are a few addresses on relations too (normally multipolygons), however, too few to be visible.

After that, the evolution of addresses through time is also interesting.

Evolution over time

Here you clearly see the import of Brussels. Skyrocketing all provinces. But address mapping in some other provinces is also gaining traction lately, however small.

Overall, I’m very surprised by the differences between the provinces, even if you ignore Brussels. And I hope address mapping in other provinces will gain some more traction.

As a final treat, I give you some graphs per province.

Antwerpen Brabant wallon Brussels Capital Region Hainaut Liège Limburg Luxembourg Namur Oost-Vlaanderen Vlaams-Brabant West-Vlaanderen

Dutch licence text

Posted by Sanderd17 on 30 November 2012 in English (English).

When I read the Dutch license text:, it still states that the data is available under CC-BY-SA on the first line.

While it has been translated in the Wiki: it looks like something is out of sync.

The other paragraphs do mention ODBL for the data and CC-BY-SA for the tiles.

Some new added feature in Google maps is, when you search for something with a boundary. F.e. my city Roeselare or my country Belgium, the boundary of that feature is highlighted.

If you search it in OSM, the boundary is not highlighted, you only see an arrow on the middle of the feature.

This is while Nominatim does offer the possibility to get the polygon outline of a feature with a boundary. Just see this query:

Wouldn’t it be nice to also have this on the main OSM site? Or are there services doing this Google-like boundary highlighting.

There is a new service launched in (and around) Belgium:

The service is launched by the mobile operator “Mobile Vikings” which focusses on smartphones and mobile internet. To the first 4000 people who enter 15 locations, they give €15 credit (that equals 2000 free SMS and 2GB free mobile data for a month).

If you look at the map, you see that a lot of POI have been entered in the first day it was online. So one might think such a model would be profitable for Openstreetmap too (off course, we can’t afford to pay €60.000, so with smaller gifts). But when you look closely, you see that a big part of the data is highly inaccurate. So people just loaded 15 POI as fast as they could to get the €15.

So I guess, if OSM wants to give quality, that kind of games are not beneficial, and we should continue to do what we do.

Universal OSM router

Posted by Sanderd17 on 3 January 2011 in English (English).


In a lot of regions, OSM has better data than Google. But still, Google data is used more than OSM data. Why? Because Google creates good tools to use their data: Navigation apps for iPhone and Android, the social latitude app ...

Therefore, I do a call for all developers to collaborate on one app: Navit.

Why Navit?

  • Because it has been ported to many devices, including iPhone, Android, Windows Mobile, Maemo, Palm Os, Mac OSX, Windows, Linux and even TomTom. So any contributions to the Navit core become available for many devices.
  • Because it's not a start from zero: Navit can already do a lot of things.

How is Navit written?
The Navit core is written in C, the device specific bindings are written in the device specific language: e.g. Java for Android, Objective-C for iOS ...

What can Navit do already?
See the wiki for this one:

What Navit can't do yet:

  • Device specific bindings are poor: e.g. in Android, you can't navigate to a contact: Navit can't access contacts, the volume button doesn't work yet ...
  • Add via points is under development, GPX backtracking isn't implemented
  • POI search (by name) or housenumber search isn't working yet. There is a nearest POI by category view though.

So if your a developer and have some time left, there is always work to do.

PS. I'm not one of the core members of Navit. I tried to help with Navit but had too little experience in C to solve real bugs.

mapping house numbers

Posted by Sanderd17 on 22 November 2010 in English (English).

Yesterday, I started mapping house numbers. Since the roads were pretty complete and almost all POIs I knew were OK, I had to find something else. I can't start drawing buildings since I don't have aerial material, so I began mapping house numbers.

Mapping house numbers is a quite huge job. When I do it, I try to map every house that stands separate. If houses stand close to each other for a longer row, I map about every 5th house and connect them with an addr:interpolation way.

I understand why there are so little house numbers in the database. It's quite a job, you can't do armchair mapping (no data available) and the result is only a few numbers on the map. You don't get to see the result that was intended: better search.

Are there any other mappers doing house numbers?


Location: 3000, Flemish Brabant, 3000, Belgium

I've completed the boundaries of Heuvelland, Heuvelland is a quite big municipality, it consist out of 8 villages of which all individual boundaries are drawn too.

The drawing of the boundaries itself happened with the help of old Popp maps which fall under PD. But since the biggest part of the boundaries didn't change in the past years, I could still use those maps. I even have drawn some roads with the help of it, roads of which I knew that still existed.

The only problem I had was with the village De Klijte. In the time of the Popp maps, De Klijte was a part of Reningelst. But with the fusion of the 70's, De Klijte became an independent part of Heuvelland, and since Reningels is not a part of Heuvelland but a part of Poperinge, I had to search the boundary between it. But I saw that there was a stream between De Klijte en Reningelst, just at the location where the rough boundaries between those two were. So I took that stream as boundary. I believe it's correct.

If someone can correct the boundaries, please do. But now, nominatim and other search engines will give more correct search results.

Location: 8956, West Flanders, 8956, Belgium

If you look at , you see that the university buildings have references. These are mapped as names since these are used on all the signs. But I also want to map the use of the building.

e.g. building B 200 is the mathematics building, A 200 is informatics ...

This doesn't have to appear on the map (it would make the map unreadable anyway) but I like to have it in the database. The only problem is that I can't find an appropriate tag for it. I don't even have enough inspiration to think of a tag myself.

Location: 3001, Flemish Brabant, 3001, Belgium

November 11 is coming, that means that a lot of Englishmen will come to Flanders Fields. I wonder if some OSM'ers will come to the Menin Gate in Ypres, or the Tyne Cot cemmetry in Passchendaele.

If you come,
welcome to Flanders (and there is still a lot of work in that region, Ypres is just a little too far away from me to go mapping there).

Look at this article (the article is in dutch, but you'll know enough with the photo)

The traffic sign says no GPS is allowed. In the entire article, they're talking about putting your GPS off and so, but I hope they mean "routing software" instead of "GPS" :-P

Otherwise it would be impossible to track the new situation of the crossing near Lummen:

The new crossing is open since today and I hope it will be adapted soon on OSM.

Location: 3560, Limburg, 3560, Belgium


I have a concave parking:

As you see, the P is appearing in the building. I know I could split the parking in 2 pieces and so there would be 2 parking symbols. But I always heard not to change the data for the purpose of rendering.

Should I show this to someone who's working on mapnik?
Should I adapt the data (split the parking)?
Or should I just leave it?


Btw: is there a new server? The updating of the map was freaking fast.

Location: 8890, West Flanders, 8890, Belgium

check changes in your area

Posted by Sanderd17 on 20 September 2010 in English (English).

Just found something new:

Did you put a complete village or even a complete city on the map and you want to check the changes people make to "your" area? You can do it with an owl:

Zoom to your area and see the changed areas of the past 24 hours. At the bottom left of your screen there's a link to create an RSS/ATOM feed of your area. That way, you can always check other mappers in "your" area (and thank them if they upload/correct something) :P

Happy mapping.


Posted by Sanderd17 on 11 August 2010 in English (English).

Is this just me, or does it happen with other people to? When I am in edit mode (potlatch) and I want to go to the slippy map, the link it sends me to has the php parameter layers=null. Which makes me see... nothing. When I delete the layers=null parameter, I can see the map.

This happens when I'm working on my works computer (windows 7 and ie 8.0), it doesn't happen on my computer (ubuntu 10.04 and ff 3.6)

Does anyone has this to? or does anyone know how to solve it?


I'm giving up

Posted by Sanderd17 on 8 June 2010 in English (English).

All I tried to do is drawing some bridges when I saw streets intersecting with waterways. But the servers were so slow I got server conflicts from my own, dubling and tripling the roads that were there, placing one node ways, POI's without tags ...

can someone clean up the mess I made?

I'll try to clean it up later (when the servers are better) if no-one does.

Location: 8000, West Flanders, 8000, Belgium