[OSM-dev] [OSM-talk] OsmNote - system for keeping and sharing notes on your OSM surveying

[Christopher Schmidt]

On Sat, Dec 02, 2006 at 06:57:07PM +0100, Dan Karran wrote:
> It wouldn't be too difficult (not sure how processor heavy this would
> be, especially for large areas) to pull out all the nodes in a
> bounding box, joined with the tags table where tag key = whatever...
> Oh, I've just checked the schema and notice there isn't a nodes_tags
> table like there is for ways. Are they stored in the tags field on the
> current_nodes table?

And therein lies the problem :) Tags are stored in a single field using
something like:
 
   foo=bar|||baz=quux

There is no way to filter on specific tags in a SQL query, because the
tags are all shoved into one field (unless something has changed
recently). This is what makes the type of behavior you're seeking
difficult in the current OSM database, and why changing the database to
match would be a significant cost.

Regards,
-- 
Christopher Schmidt
MetaCarta