On 18 May 2009, at 01:38, Matt Amos wrote: > On Sun, May 17, 2009 at 11:32 PM, MP <singular...@gmail.com> wrote: >>> http://en.wikipedia.org/wiki/TopSat >>> http://www.qinetiq.com/home/defence/defence_solutions/space/topsat.html >>> >>> Apparently you can rent it for £25k a week... easily within the >>> ambition of >>> donate.openstreetmap.org. >> >> How large part of earth could be imaged in that timeframe? >> Topsat have 2.5m resolution, which is quite fine for most areas, >> though less than aerial imagery ... > > 2.5m sounds about the same as Y!, so its even enough for rudimentary > building mapping. but thats the black-and-white figure, the colour > resolution is about 5m. :-) > > out of interest, is there a link to the £25k figure? i couldn't find > any pricing information on the net anywhere...
Sound great, but in the mean time we can of course buy commercial photography including the right to derive mapping at a cost of about $17 per sq km which is affordable for compact European cities but not for large rain-forests! The Gaza strip cost £4,500 and photography for the Birmingham conurbation would be about £5,000. A small UK town would be <£5000. The West Midlands are looking for sponsors at present. http://wiki.openstreetmap.org/wiki/Aerial_photography_funding_appeals Regards, Peter > > > i guess hiring it for any fixed period is a bit hit-and-miss, since > satellite imagery will be affected much more by cloud conditions. > >>> MP's point about what you do with the vast quantities of data >>> that you get >>> is well-observed, of course. But we like a challenge. >> >> One thing is having the data on ground - entire world (510,072,000 >> km²) from Topsat in 2.5m resolution will have ~ 245Tb of uncompressed >> data (you'll get to about 1/3 of that if you discard imagery with >> just >> sea), which is lot, but perhaps still manageable. > > at 5m in colour, thats about 20.4 Tb for the land portions of the > world. compressing in JPEG, which compresses about 2:1 based on their > sample images, thats 10.2 Tb - or 1,400 gmail accounts ;-) > > or it would cost $20,110 to put it into S3 and host for a year > (without downloading) > > or about £1,400 to stick it on some 1Tb SATA drives in a RAID1+0... > > (interesting co-incidence which implies that each gmail account at > capacity costs google about £1 in storage...) > >> But you have to >> either store some non-trivial part of it on the satellite (that is >> not >> as easy as on earth where you can buy some server with RAID and plug >> it into wall) while the satellite does not have direct visibility of >> the earth contyrol center where it can relay stored images (and then >> you have some means to transmit large amount of the data while the >> satellite flies over the earth control center) or have multiple >> ground >> stations or bunch of another satellites that relay the continuously >> transmitted data. > > i have to assume that qinetiq have some way of solving this. > > also, would it be worth it as a PR stunt for qinetiq to just use up > whatever spare capacity they have when maneuvering or between clients > and give us whatever gets photographed...? anyone know anyone at > qinetiq? > > cheers, > > matt > > _______________________________________________ > talk mailing list > talk@openstreetmap.org > http://lists.openstreetmap.org/listinfo/talk _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
