HDF-SDS Read Error

[Don Hooper]

Ajayan,

I errored; it's not "scan,longitude,latitude" you want, but "z,x,y".  I
didn't much care for the plots I got from this DDF:
DSET ^3B42.980101.3.6.HDF
DTYPE hdfsds
UNDEF -9999.90
XDEF 1440 LINEAR -180.0 0.25
YDEF 400 linear -49.875 0.25
ZDEF 1 LEVELS 1
TDEF 1 LINEAR 03:06Z01jan1998 3hr
VARS 2
precipitation=>pcp 1 z,x,y precip
relativeError=>err 1 z,x,y error
ENDVARS

As for alternatives, the xdfopen interface should work.   However, I
liked even less the plots I got from this DDF:
DSET ^3B42.980101.3.6.HDF
UNDEF -9999.90
XDEF longitude 1440 LINEAR -180.0 0.25
YDEF latitude 400 linear -49.875 0.25
ZDEF scan 1 LEVELS 1
VARS 2
precipitation=>pcp 1 99 precip
relativeError=>err 1 99 error
ENDVARS

I think this is an HDF-EOS file, so working with it is tricky.  Based
on my reading of the metadata, which I find confusing, the longitude
goes -180 to 180, not 0 to 360 as you indicated.  But, who knows?  I
would use a tool that is cognizant of HDF-EOS metadata, such as NCL
from NCAR, to try looking at this file.  Hell, if I was a dab hand
with NCL I'd have tried it myself.  %}

-Hoop
> From ajayan at jamstec.go.jp  Thu Apr 13 19:48:10 2006
>
> Hoop,
>
> Is it possible to read this file without using "dtype hdfsds" ?
> I find that xdfopen with out "dtype hdfsds" also gives error.
>
> Changing VARS line with scan,longitude,latitude also gives the same
> error.
>
> best,
> Ajayan
> -------------------------------------------------------------
> On Thu, 2006-04-13 at 07:16 -0600, Don Hooper wrote:
> > Ajayan,
> >
> > I'm not an expert in "dtype hdfsds"-style DDFs, but, I'm thinking that
> > the "99"s in the lines between "VARS" and "ENDVARS" should change to:
> >     scan,longitude,latitude
> > in both cases.  Just a thought....
> >
> > -Hoop
> > > From owner-gradsusr at LIST.CINECA.IT  Thu Apr 13 06:34:18 2006
> > >
> > > I have used the following descriptor file to open an HDF file
> > > using gradshdf (GrADSVersion 1.9b4 in FC3) using open <file.ddf>.
> > >
> > > I get the error HDF-SDS Read Error for dtype FLOAT32.
> > >
> > > Any idea, about where I am going wrong? Any other suggestion to open
> > > this file in Grads?
> > >
> > > DSET ^3B42.980101.3.6.HDF
> > > DTYPE hdfsds
> > > TITLE This is only a test
> > > UNDEF -9999.90
> > > XDEF 1440 LINEAR   0.12500000 0.25000000
> > > YDEF  400 linear -49.87500000 0.25000000
> > > ZDEF 1 LEVELS 1000
> > > TDEF 1 LINEAR 03:06Z01jan1998 3hr
> > > VARS 2
> > > precipitation=>pcp    0  99 Precipitation
> > > relativeError=>error  0  99 Error
> > > ENDVARS
> > >
> > >
> > > The HDF file used is
> > > ftp://disc2.nascom.nasa.gov/data/s4pa/TRMM_L3/TRMM_3B42/1998/001/3B42.980101.3.6.HDF.Z
> > >
> > > best,
> > > Ajayan
>