Glenn Plas has commented on the following diary entries

Post When Comment
Evolution of road network length in Flanders 7 months ago

Very nice work Joost, I love stats. Tx for the work. You seem to have plenty of bloggin time ;-)

Don't know what to think of it of this research over 2 years ago

We are talking about a change of max_speed on 1 single road (or is it 2?). How this can be representative in nature is beyond me.... The sample size is way too small to be significant.

It sure felt more like a Virtual Geocache game in OSM. "I've hidden a needle , now you figure out which haystack it's in"

Don't know what to think of it of this research over 2 years ago

Thank you @woodpeck. Clear signal, his account is probably a dud however. I don't think this research was very academic in nature, it sounds like an idea a minor would execute. Too bad it went unnoticed for so long.

Don't know what to think of it of this research over 2 years ago

This is a terrible way to 'test' the community. So we have 3rd parties introducing easter eggs into OSM for whatever reason. maxspeed is an important tag, it should not be messed with in this way. How is this measuring quality anyway ?

Address evolution in Belgium over 2 years ago

Love this stats stuff... The nodes are indeed needed from time to time, I always make sure that it's on an entrance if possible, very few are amenities with addresses. I also think that the quality of the areas I did was excellent. I've been looking elsewhere (Mechelen for example) and there are spots where I find 20 nodes on the same spot. The errors in Mechelen I wrote them down and after 2 hours I had 3 A4's full. I love mapping this stuff but I can't spend twice the time on entering all those errors in LARA. I wish we had some more automated way to push this upstream.

The only remark about the data that really bothers me are numbers like this : '73S' '72K' .. Really weird ones, it's not like appartment A,B,C , just random I see numbers with O after it. It does look like the source of them is interpolation. I do not transfer those numbers, that is why in the end, there will always be incomplete streets in the tool, even though in OSM it's ok.

Also, your remark about me changing building=house into building=yes , I figured out that the terracing tool was doing that so before I merge the numbers with buildings ( I do them all manually) I add building=house on the nodes first. Then the terracer will warn me when the existing building has been tagged differently. I had to redo thousands of houses I thought I finished up.

Trying to get on touch with (semi) nearby Belgian mappers about 6 years ago

Mmm... I actually found this while viewing that changeset concerning Tongeren. There are OpenGeoDB tags in there that got my attention.

I think this is the alternative datasource I intuitively suspected to exist.

Trying to get on touch with (semi) nearby Belgian mappers about 6 years ago

By the way, Bing has the same issue. I noticed that when you revgeocode coordinates in a city that could potentially returns more than 1 hit for the cityname, they just drop the postal code from the resultset. That's why I have that postal code service up and running to complete Bing data when I need it. Not always but I saw a nice corolation between my own problems and Bing's results

Trying to get on touch with (semi) nearby Belgian mappers about 6 years ago

That first URL is pasted double somehow but seems to work despite the crap in the url.

A better url is,fr,en-gb;q=0.8,en;q=0.7

Trying to get on touch with (semi) nearby Belgian mappers about 6 years ago

Have you tried building a gazetteer service ? Allmost reverse geocodings end up without a postal code in the resultset.

My patchwork solves that outside the OSM realm,fr,en-gb;q=0.8,en;q=0.7

If you follow the gazetteer installation instructions as-is you don't get the same result from the OSM run nominatim service. So I assume they have other database sources.

A good example of badly tagged cities WAS 'Tongeren' It had the standard and the french name set but not the :nl one. So in the resultset with language preferences set to prefer dutch first, then french and if all else fails you get the plain name tag back.


It DOES give you back the city name wich I use to translate the postal code but obviously there are many dubious names in our little country which makes that not as easy as one would think.

So in essence, the big question is why does my own nominatim installations (I do those with my eyes closed after 20 times now ;-) fail to return a postal code.

Scraping is out of the question as Google's data is full of easter eggs (I found 5 already in Belgium).

I ended up writing a PHP class just to see how different those results are among the top 5 players.

The development version is different in the nominatim service implementation, the master branch is written against the standard nominatim service, the former is written against my own solution.

I've made a list of postal codes coming from different data sources. (De Post) But OSM data is filled with Village/Town names that share a postal code with another city so you have a 1 to m relation. I use proximity to solve that but as you can see here:,en;q=0.8,fr;q=0.5

Big cities have many codes and they are all very close to eachother so that solution won't work perfectly.

Also the other way around,en;q=0.8,fr;q=0.5

Also returns 2 results. So which one is it?

I think by now I probably have the most complete database of cities/postal codes mappings in Belgium. Since I manually include failed geocodings I encounter in the logs.

I just don't know enough about the inner workings of gazetteer to fully understand where that problem occurs.

Thanks for discussing this!

mapping house numbers about 6 years ago

Hi fellow Belgian,

I do housenumbers where I can. Which is not really that often. I'm using the nominatim imports quite heavily and I believe the bigger problem in Belgium is the missing postal codes from the resultsets.

I only dug into that gazetteer code as far as I had to to just patch my own postal code stuff on it -which is quite imperfect- With distance checking from reference points (which works when they are far away, but doesn't work when you have like 7 different zones in Antwerp of Brussels for example)

We have tons of issues having the french/dutch names for cities for example. I can't match 'Forest' easily, since that could mean 'Vorst' but also 'Vorst-Forest' but there is also a town called 'Forest' in the Walloon area. So it's ambiguous all the way.

I would rather see the postal codes fixed first.

Make SURE you get the buildings Plugin for JOSM as that will speed up your work drawing buildings in a factor 10. I've mapped about 4000 houses this week over here ;-)

Trying to get on touch with (semi) nearby Belgian mappers about 6 years ago

By the way, what is ONK ? I failed to google anything :)

Trying to get on touch with (semi) nearby Belgian mappers about 6 years ago

Hi both!

The devices we are using are coming from It's a dutch manufacturer who has taken the professional market in a storm. They are absolutely ace. The data comes in over GPRS/EDGE of course. I'm not sure that going the open source way would benefit OSM. I do have lots of tracking data I can easily anonymise as the only reference is the device's Imei number.

I'am writing a 'light' version of what we call the 'socket server' which stores all incoming data. They are not cheap however but they are supported with open code. (not open source I guess since it's lacking licenses. See here for the capabilities of those tracers:

You can check a development map of mine here:

It's my own car I'm experimenting with. Notice the accuracy of this device, it CAN but doesn't have to be used with timers, it checks the direction changes, distances. I've seen like 5 different devices, all kinda sucked until we found this supplier. Currently we have about 2500 running in the field.

It's all implemented in PHP since that was the only available Class about 5 years ago when we started out. No ideally but we have no performance issues due to PHP. I'm implementing a SQLITE backend which totally rocks. Having Mysql as a backend was a very bad idea since it didn't scale at all when we needed it. Hence we use MariaDB now.

Thanks for the comments.

Experience about 6 years ago

Make sure to map the idiots house with full address ;-)

And BTW, did you map the police station inside ? Including vending machines etc?

A friend of mine is a police woman and she has stopped some people with laptops in front of the door being alarmed by worrying citizen. Most of the times its some kids abusing some poor sods open wifi... I have issues with them having enough knowledge about technology to fully understand if and when someone is breaking any rules. These people seriously overreacted, imagine your mum being robbed in the meantime and they have no personal 'available' to deal with it. You should atleast voice yourself and do some OSM PR maybe....

Bring along a camera next time and take pictures of innocent things where everyone can see you, right away, everyone will think you are a photographer, no need to explain uploading pictures to the laptop. Don't fotograph their houses. Or bring a fluo-jacket in yellow/orange. There is no burglar that wears that, and you look kind of official. After a while it's fun deceiving people, they all think you're doing important stuff.