Re: DODS/Binary format

[Jonathan Callahan <callahan@xxxxxxxxxxxxx>]

Long,

As you have discovered, some datasets lack most meaningful metadata
including 'use' metadata required to understand what region of space the
X and Y axes represent.  After poking around I eventually arrived at
this URL:

  http://daac.gsfc.nasa.gov/daac-bin/nph-ff/DODS/catalog/

There is precious little information available through the DODS .das
file:

http://eosdata.gsfc.nasa.gov/daac-bin/nph-ff/DODS/catalog/erythemal-cat.dat.das

This is not really a fault of Ferret or DODS or even FreeForm (whenever
you see /nph-ff/ you're connecting with a DODS FreeForm server).  The
person who created the FreeForm configuration file did only the absolute
minimum to get the data into a DODS server and we are left guessing what
the data and even the axes represent.

So we need to use Ferret to add some sensible 'use' metadata.  I've
appended a quick Ferret session to let you know what you've got to do
with this kind of data.  These are my best guesses of what to do but
you'll have to use your own expertise or contact someone at GSFC to
figure out what's correct.


Good luck,


-- Jonathan Callahan

!--------------------------- Feret script
----------------------------------
use
"http://daac.gsfc.nasa.gov/daac-bin/nph-ff/DODS/catalog/health/toms/erythemal/EPTOMS_UVM0001.bin";
show data
shade toms_eryth
!
! This could be a global dataset.
! Do I see South America and the Andes at X=85?
!
message/quiet

show grid
list `360/288`
!
! 1.25 deg by 1.00 deg is a strange grid but who knows.
!
message/quiet

define axis/x=-180:180/npoints=288/modulo longitude
define axis/y=-90:90/npoints=180 latitude
define grid/x=longitude/y=latitude toms1g

let a = toms_eryth[gxy=toms1g@asn]

shade a
go land
!
! If I new more about UV data I might be able to decide
! whether this was a reasonable plot or not.
!

!--------------------------- Feret script
----------------------------------



Long Pham wrote:
> 
> Jonathan,
> 
> I'm currently using the latest Ferret 5.22.  I'm trying to access
> data from
> 
> http://daac.gsfc.nasa.gov/daac-bin/nph-ff/DODS/catalog/health/toms/erythemal
> /EPTOMS_UVM0001.bin
> 
> Thank you.
> 
> ----- Original Message -----
> From: "Jonathan Callahan" <callahan@pmel.noaa.gov>
> To: "Long Pham" <pham@eosdata.gsfc.nasa.gov>
> Cc: <ferret_users@ferret.wrc.noaa.gov>
> Sent: Monday, November 05, 2001 4:07 PM
> Subject: Re: DODS/Binary format
> 
> > Long,
> >
> > You'll have to give some more information.
> >
> > What version of Ferret are you using?
> >
> > What is the DODS URL for the data you're accessing?
> >
> >
> > -- Jonathan Callahan
> >
> >
> > Long Pham wrote:
> > >
> > > Hi,
> > >
> > > I'm currently trying to retrieve/use binary files via DODS in Ferret,
> but
> > > I'm having some problem.  Has anyone had success in this area? Could
> > > you send me sample file of what you did?
> > >
> > > Thanks,
> > >
> > > ~ Long ~
> > > ___________________________________________________
> > > ___________________________________________________
> > > Long B. Pham                                       Ph.:  (301) 614-5132
> > > GSFC Earth Sciences DAAC                 FAX: (301) 614-5268
> > > NASA-GSFC, Code 902
> > > Greenbelt, Maryland 20771
> > > Email: pham@daac.gsfc.nasa.gov
> > > ___________________________________________________
> > > ___________________________________________________
> >