RE: Offset threshold problem

Curtis L. Olson writes:
>
> David Megginson wrote:
> 
> > Erik Hofman wrote:
> >
> >> For what I've seen so far the STRM data incorporates terrain 
> >> elevation due to stables, farm houses, trees (or rather small woods), 
> >> tall buildings, etc.
> >>
> >> So in reality the data is too accurate for our needs.
> >
> >
> > That is correct -- once we go below 3 arcsec, we'll start seeing large 
> > hills in urban areas that are really skyscrapers, etc.
> 
> 
> We also see a lot of noise in the data even at 3 arcsec resolution ... 
> They had a  huge antenna (60m) that they extended from the shuttle.
> 
>     http://www.shuttlepresskit.com/STS-99/payload57.htm
> 
> This had a natural oscillation that shows up in the data as well.  They 
> had some scheme for trying to account for or correct for this, but 
> perhaps that didn't work out as well as they hoped, or no one managed to 
> figure out the math?

Patience, this data is relatively new and this is just the 'first' distribution.

Secondary processing can and will remove the systemic noise,  but 
nothing short of actual ground survey will remove that part of the signal
due to actual objects built apon the surface.

In fact if you think about it elevation of the surface of the earth is bumped 
where there is a building from some perspectives :-)

Cheers

Norman