[OSM-talk] Satellite for OSM

[Matt Amos]

On Sun, May 17, 2009 at 11:32 PM, MP <singularita at 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...

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