[Openstreetmap] expiring GPS tracks after 30 days

[Tom Carden]

It's been suggested GPS tracks should expire from OpenStreetMap after 30 
days (for example).  This is to encourage people to upload AND annotate 
their trails, not just dump them on OSM for all eternity.

Rather than discuss it on the wiki, I think it's best to bring the 
discussion here.

(So you can follow the discussion, so far it's all here:
http://www.openstreetmap.org/newwiki/index.php/Roadmap_For_Version_1.0
And Lars has also commented here:
http://www.openstreetmap.org/newwiki/index.php/GettingTheSource
-- Lars, perhaps bugs with the web software should go direct to Steve?)

The following is my own opinion...

I think expiring trails is a good idea.  I'm not advocating throwing away 
data, just removing it from the interface if nobody is using it.  I suggest 
that reinstating data should be possible but not encouraged - perhaps it 
could only happen once per user, something like that.

The idea is that GPS points would be removed from the editing interface if 
nobody has done anything with them.  Until we have decent caching for 
images, everything gets drawn individually, and a couple of thousand 
(million) GPS points causes significant lag.  I think the emphasis should be 
placed on the maps, not the trails.

Some background: GPS trails are just one planned way to get data into OSM, 
other methods are in development. For example, tracing out of copyright 
maps.  GPS tracks are a good sanity check if we're annotating old maps, and 
they give a great idea about where we should focus (we want maps first where 
we have lots of activity), but they aren't the be all and end all.

There are interface solutions to this problem too (like offering check boxes 
for available trails), but I think expiring trails correctly places the 
emphasis on annotating and translating raw data into maps, not on storing 
people's daily movements.  On the wiki, Lars has suggested a separate 
repository for GPS trails - how would that work?

Thoughts on this would be appreciated,

Tom.