RE: [Tcl-nap-users] writing HDF files

[<Pet...@cs...>]

Hi salah,
   =20
   You seem to have sorted out how to write multiple SDSs and
attributes.=20

I am not sure if you are aware but you need to be careful mixing NAOs
and tcl commands.  Your example below is a bit dangerous if you want to
use x for anything else.  NAOs have a reference count which counts the
number of tcl variables pointing at them. If the NAO reference count
goes to 0 then the NAO kills itself. In order to create a relationship
between the NAO and a tcl variable the nap command needs to be used:

nap x =3D [nap_get hdf .......]

In the above case the NAO will have a reference count of 1 and be
attached to x so that if x gets unset the reference count on the NAO
will be decremented and if the reference count is zero it will
disappear.
In your example, although x points to the NAO the reference count on the
NAO will be 0. In this case the NAO is a bit smart an says, hey, you
just created me, even though I have a zero reference count I must be
needed for something so I will hang around until something happens. In
your case you wrote straight back to an HDF file. However, once that
event happened the NAO will disappear so trying to do anything further
with x/NAO will not work.  It is important to understand this, because
if you do not you can get into lots of trouble.

You cannot get rid of the fillvalue at present using nap.  I doubt that
this is causing a problem. I would just check the contents of the output
file with hdp, I would then use the NAP HDF display utility to have a
look at the contents of each file and make sure there is nothing else
wrong.

Cheers

Peter




		-----Original Message-----
		From: tcl...@li...
[mailto:tcl...@li...] On Behalf Of salah
jubeh
		Sent: Wednesday, 8 March 2006 11:03 PM
		To: NAP
		Subject: [Tcl-nap-users] writing HDF files

		Hi guys
		=20
		I tried to genarate HDF files out of NAOs.
		=20
		set x [nap_get hdf c:/sampels/p14/gdal/p14_4.hdf
"3-dimensional Scientific Dataset"]
		$x hdf sa.hdf sa
		nap_get hdf -list sa.hdf
		-------
		sa
		sa:_FillValue
		I want to ask how i can add SDS to the file like
transformation matrix and projection.=20
		=20
		Regards
		=20

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