Cleaning up the mess

Posted by egore911 on 26 July 2008 in English (English).

I visited my family last Wednesday. I took some GPS traces in Wiesbaden Breckenheim, Igstadt and Bierstadt and wanted to check if there are any improvements possible. And there were!

Many parts of Wiesbaden were created by using Potlach. I personally dislike this program since it does seem to do some nasty stuff. So I spent my friday night and the whole saturday fixing up the mess that was created using potlach.

Isn't there any validation available in Potlach like it is in JOSM? I only did the eastern parts of Wiesbaden and there were more than 500 warnings.

Anyway, now it's done and Wiesbaden is much better (more street names, fixed complex crossings and MANY MANY warings fixed)

Comment from Richard on 26 July 2008 at 20:15

Please be more specific: what "nasty stuff" or "mess" do you mean? Throwing around pejorative language doesn't actually help at all.

The Maplint validation layer is indeed available in Potlatch, you might find that out if you tried it.

Comment from mabapla on 27 July 2008 at 23:06

Hello Richard.

I can add four points here about Potlatch:
1) It seems that Potlatch does not make the "catching radius" bigger when the zoomlevel is rather low. On the other hand, people don't like to zoom in beyond the level at which the YWMS images are still shown - which is understandable. The result is a lot of unconnected ways instead of a junction when people don't click exactly on the other way.
This may not be noticeable on the rendered maps but is deadly for any routing application as it will produce strange routes as it has to think that the two ways are not connected.
2) Another error that I first found difficult to find is duplication of ways. You have two ways on top of each other, with different attributes. (I wondered why Maplint said "residential without name" but the name had a way.) Often in connection with 3) and created_by=Potlatch.
3) I keep seeing an error (that is revealed by the validator plugin in JOSM) and that is duplicated nodes, i.e. two nodes at exactly the same location. Often, this also means two ways that are again not connected according to the data. Again this may not matter for maps but is terrible for routing algorithms. In all cases I have seen (like 100 or so over the past months, no kidding) they were created_by=Potlatch XYZ.
3) Another thing, also revealed by the validator plugin, is duplicated way nodes. That means a node is in the way twice. Not as much impact as the others, but still just wrong and created_by=Potlatch.

I'm sure I'm not the first to notice these errors and it seems nothing has improved since, so I didn't bother to report them anywhere yet.

Greetings, Markus

Login to leave a comment