[OSM-dev] NameFinder - problems building index
david at frankieandshadow.com
Mon Jan 21 17:57:32 GMT 2008
On 21/01/2008 17:28, Nick Black wrote:
> Ok, the problem was the namefinder.sql - I've checked in an updated version.
Yes, sorry. You got to it before I did. That was a side effect of the
change to API 0.5.
> If its taking five days to run on planet right now, its not a viable
> option. Have you (David) or anyone looked at running it from a diffed
Yes - I think I said previously, I have a design and I am about half way
through coding it.
The problem is that it isn't enough to just process a diff through the
existing algorithm - for example, if a way is deleted with some name,
that may require a node or way which is nearby which hasn't been changed
so doesn't appear in the diff to be "revealed" in the name finder.
Example: "Parkside School" in Cambridge is represented by both by a way
(area) and a node, and there is also a Parkside School in Chester, say.
The name finder search has two entries, one for the Cambridge name,
which happens to be derived from the node, and one for the Chester. The
node is removed. The name finder has to replace this with the area from
Cambridge, so has to have reference to the whole data set in order to
determine this because the area doesn't appear in the diff. Similarly,
if the diff adds a name, it may not want to be added to the namefinder
search as it may be very close to another entry with the same name.
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