[Freegis-list] Re: VMAP0/TIGER/SRTM30 data via BitTorrent
fulton at cmu.edu
Sun Apr 3 19:20:14 CEST 2005
Frank Warmerdam wrote:
> 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:
> 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?
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