[Openstreetmap-dev] key/value system question and broken osmServerHandler.getFeatureValues

Immanuel Scholz immanuel.scholz at gmx.de
Sat Sep 17 01:29:57 BST 2005


Can someone please acknowledge my understanding of the key/value system?
If I understand
http://www.openstreetmap.org/wiki/index.php/Key_Value_System correctly
(I never heard of "del.icio.us/flickr" before ;), then:

- Keys exist independend from any other stuff in osm. There is a list of
all keys in the server, regardless of whether they are used or not.
- A key can be assigned to any object. "Object" means all
	- node
	- point of interest (crippled node)
	- segment (line)
	- street (several lines)
	- area (several nodes)
	- other keys (e.g. displayLogo assigned to motorway)
- when a key is assigned, a "value" describes the key<->object
connection. So the trippel (key, value, object) is stored.
- keys and value both are strings. Interpretation of these strings are
application dependend (something like "please use sane values")

While I am on it: What's broken with

 osmServerHandler.getFeatureValues(int nFeatureType,
	java.lang.String sAreaUID,
        java.lang.String sToken)

The first parameter is an object type descriptor, missing some types
(only area, poi, street and segment seems to be supported. How to ask
for "node" and "key" values?). The second parameter is an uid, but the
wrong type: String instead of the usual int. And the last is the token,
which used to be the first parameter in all other functions...

Ciao, Imi.

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