[OSM-dev] 0.6

Raphael Studer studerap at gmail.com
Wed May 7 11:13:12 BST 2008


>  You also have to realise just how many tags there are.
>  On nodes and ways there are close to 1 billion tags, comprising of
>  about 50 million distinct key-value pairs (this was the last time I
>  counted which was a while back).
>
>  So while you'd save on space, the table join to get the tags back
>  wouldn't be that cheap.

I guess there are a lot of key-value pairs, but joining tables is what
relational databased are made for.

>  As far as typos go, well, the typos are in there too so they'd turn up
>  in your autocomplete if you used it verbatim. You also have to
>  separate out tags used on nodes, tags used on ways, and tags used on
>  relations.

The api change would be a good time to clean out most of the typos.
with the node_tags, way_tags and relation_tags table (sorry i've completly
forgotten these above),  they are allready separated.

>  As far as your map features extension goes, this wouldn't need to be
>  real-time so it could be done on a different machine by processing the
>  planet dump. I think there would be a lot of value in a site which
>  could achieve something along the lines of an extended TagWatch, but
>  you probably don't need an API change to do it.

I agree with you, that the map features dosn't need to be created realtime.
An extended TagWatch could probably be a better solution than a map
feature extension. But I guess, TagWatch would also profit from this change.

The changes would more be an enhancement of the API (getNodeTags/
getWayTags/getNodeKeys...) than a change.

Raphael




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