Re: Newbie needs help...

[Paul van Delst <pvandelst(at)ncep.noaa.gov>]

Bruce Bowler wrote:
> 
> David Fanning wrote:
> >
> > Bruce Bowler (bbowler@bigelow.org) writes:
> >
> > > I'm willing to try this "thinking outside the box" thing for a while,
> > > but I can't see the box.
> >
> > There is no box. (But see more on spiritual development, below.)
> 
> Then what did I trip over last night on my way to the
> toil<del><del><del><del>reading room?
> 
> Fortunately, I think I landed on the outside, and I didn't hurt
> myself...
> 
> As I hit the ground, I realized that displaying the data and extracting
> the data value at some lat/lon are 2 entirely different processes.  I
> can use Liam's image_map to display it and came up with clever (but as
> yet untested) way to extract the data.
> 
> Given a target lat/lon and BHAlat and BHAlon, how about (in pseudo-code)
> 
>         possiblelats = where(BHAlat eq lat{+/- some epsilon})
>         possiblelons = where(BHAlon eq lon{+/- some epsilon})
>         possiblevalues = intersection(possiblelats,possiblelons)
> 
>         if number of possiblevalues is between 1 and 10, printout the data
>                 otherwise adjust epsilon either up or down and try again.
> 
> Does that sound like it ought to work (and in some time less than a
> glacial epoch) ?
> 
> Bruce

It seems to me that the problem is one where the transformation from array lat/lon to map lat/lon
(for viewing as a contiguous eye-candy type of image) is linear, but the reverse is decidedly
non-linear. Your nearest neighbour search above seems like a workable solution since your
referencing the original lat/lon array.

paulv

-- 
Paul van Delst                 A little learning is a dangerous thing;
CIMSS @ NOAA/NCEP              Drink deep, or taste not the Pierian spring;
Ph:    (301) 763-8000 x7274    There shallow draughts intoxicate the brain,
Fax:   (301) 763-8545          And drinking largely sobers us again.
Email: pvandelst@ncep.noaa.gov                    Alexander Pope.