[OSM-talk] labels for road names and route designations

[Immanuel Scholz]

Hi,

> Ah... My understanding of what a label is must be wrong. This goes back to
> my other mail about the need for a glossary of terms.

For the programmers part of OSM, the word "label" is not well defined (yet).

My current understanding is (please, cite me in the wiki if you start a
glossary ;-):

There are "properties" which is a synonym for "tags" (a list of key/value
pairs), "keys" which are the name of one property and "values" which are
user defined strings associated to a key.

Sometimes, "property" (one pair of key/value) is carelessly used as a
"value" only. "tag" (synonym for "property") may be used as just a key or
just a value.

"attributes" are an other synonym of "properties".


(The sentence "The foo is bar on dingus" means: "The key 'foo' has the
value 'bar' on the object 'dingus'." ;-)



> In terms of using XML, that would be good as a transfer format. But, how
> is the data actually held. There doesn't seem to be anything in the wiki
> about that. I know there are some servers, but what database system is
> being used?

First of all: From the talk at openstreetmap.org's point of view, it should
be of (almost) no interest, how the things are organized behind the scene
;-)

But the properties are equal seperated pairs of strings that transferred
over the new as a semicolon seperated string, terminated by a single
semicolon. The server saves this in database as a varchar in exact this
format. I don't know what happen if you try to specify a semicolon as key
or value ;-)

There is a proposal to change the way it is transfered so that every
property is in a single xml tag, but this is not implemented in the server
yet. (I think this is only supported by JOSM yet).


> Is it specific to this project? There isn't a high level overview about
> how all this fits together.

Personally I never liked second level documentation (it seems to be out of
date the time it is written.. ;). But if you want to create one, do it. No
problem here ;-). I will fix anything I am aware of in the wiki.. :---)


> There also seems to be some problems when two people are editing the "same
> area".

Yes.


> Which is a point I was curious about (but, I'll leave that for
> another time)

Why are you curious? This kind of problems exist in every heavily
distributed system. I would have been surprised if OSM does not have any
problems with two people working on the same area at one time ;-)


Ciao, Imi.