[Freegis-list] Re: VMAP0/TIGER/SRTM30 data via BitTorrent

[Sean Fulton]

Frank Warmerdam wrote:
> Folks,
> 
> A few of us have been thinking about use of the BitTorrent protocol 
> in the geospatial area.  Our conclusion is that it's greatest use is
> in distributing large public (free) geospatial datasets.  To that 
> end we have setup a modest experiment to see how useful and popular
> such a service might be.  
> 
> BitTorrent, for those not familiar with it, is a peer-to-peer file
> sharing protocol.  It's distinguishing factor is that the "server" can
> scale to handle large numbers of clients without a large increase in 
> bandwidth by virtue of forcing clients to trade parts of the downloaded
> files with each other rather than having to send a full copy of the file
> to all clients.
> 
> To test out the utility of BitTorrent in this field we have prepared and
> "seeded" a few fairly large, and reasonably popular datasets.  These include:
> 
>  o TIGER 2004fe: Full Tiger data for the full USA. 
>  o VMAP0: All 4 VMAP0 CDs - various vector data for the whole world. 
>  o SRTM30+: SRTM derived DEM data at 30 second postings plus Bathymetry data. 
> 
> The torrents can be found at:
> 
>   http://uo.space.frot.org/?GeodataTorrents
> 
> I welcome feedback, suggestions, additions, and even boos and hisses. 
> 
> Best regards,

This is very cool, by the way. However, the problem with Bittorrent is 
that it only to work well with popular files, i.e. files that with a lot 
of downloaders. I tried downloading the vmap0 data via those torrents 
and it was taking an excrutiatingly long time. I gave up and downloaded 
directly from NIMA.

Perhaps you could get a couple other sites to help seed(is that the 
right word?) the torrents?

	Sean