| HDF_Browser Woes [message #53803] |
Thu, 03 May 2007 08:55  |
David Fanning
Messages: 11724
Registered: August 2001
|
Senior Member |
|
|
Folks,
Does anyone have the foggiest idea of how HDF_BROWSER works?
I'm trying to figure out what is in an unknown HDF file.
When I select the READ button, something is returned,
but I can make no sense of it whatsoever. Help (or suggestions
for using something OTHER than HDF_BROWER) is appreciated.
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
|
|
|
|
| Re: HDF_Browser Woes [message #53881 is a reply to message #53803] |
Thu, 03 May 2007 14:14  |
George N. White III
Messages: 56
Registered: September 2000
|
Member |
|
|
On Thu, 3 May 2007, David Fanning wrote:
>> Sorry... my head is spinning..... they don't have a clue what's supposed
>> to be in the file (in any way, shape or form), yet they know that they
>> need to read it????
>
> Clearly you are not on the front lines teaching people
> how to use IDL or your head wouldn't be spinning. (Unless,
> of course, from the inevitable overdose of Prosaic.) But,
> yes, pretty much. They know their professional life
> depends upon it, but they haven't yet learned which poor
> sucker had already done all the hard work and will be
> willing to share it with them.
When they do catch up with her, chances are (given the lack of information
and the time frame when hdf was popular) she will be suffering from some
form of senile dementia, so good luck getting any useful information.
> That's, uh, sort of my role in life. :-)
Data rescue -- fast growing field.
--
George N. White III <aa056@chebucto.ns.ca>
|
|
|
|
| Re: HDF_Browser Woes [message #53882 is a reply to message #53803] |
Thu, 03 May 2007 14:10 |
George N. White III
Messages: 56
Registered: September 2000
|
Member |
|
|
On Thu, 3 May 2007, David Fanning wrote:
> Does anyone have the foggiest idea of how HDF_BROWSER works?
> I'm trying to figure out what is in an unknown HDF file.
> When I select the READ button, something is returned,
> but I can make no sense of it whatsoever. Help (or suggestions
> for using something OTHER than HDF_BROWER) is appreciated.
I tried HDF_BROWSER -- it needs tweaks for each different style of
hdf 4 file.
Sometimes converting hdf4 to hdf5 produces a much simpler file. There is
an h4toh5 utility to do this. The free R stats package has an hdf5 reader
that can be used to get a 2nd opinion on whether the hdf5 file makes any
sense.
--
George N. White III <aa056@chebucto.ns.ca>
|
|
|
|
| Re: HDF_Browser Woes [message #53884 is a reply to message #53803] |
Thu, 03 May 2007 13:18 |
James Kuyper
Messages: 425
Registered: March 2000
|
Senior Member |
|
|
David Fanning wrote:
> Richard Edgar writes:
>
>> (Sorry if this is distracting you from the task at hand ;-) )
>
> Well, to tell you the truth, I just found the Modis Level 1B
> Product User's Guide, so I am in the process of *looking*
> for distractions just now. :-(
You have my sympathy :-). If you have any suggestions for improving
the Guide, I'd appreciate hearing them.
Are the L1B product files the ones you're trying to examine with the
HDF_BROWSER()? If so, I hope that the filespecs which you can find at
<http://www.mcst.ssai.biz/mcstweb/L1B/product.html> will help.
You can also find L1B filespecs at <https://modaps.nascom.nasa.gov:
9500/software/>, along with the actual source code and and static
input files for all MODIS Land, Atmosphere, and Inhouse PGEs. It's a
password protected site; you have to register at <https://
modaps.nascom.nasa.gov:9500> before you can use it. However,
registration is just a legal formality to make sure you've signed the
NASA Software Usage Agreement.
|
|
|
|
| Re: HDF_Browser Woes [message #53886 is a reply to message #53803] |
Thu, 03 May 2007 12:01 |
David Fanning
Messages: 11724
Registered: August 2001
|
Senior Member |
|
|
Richard Edgar writes:
> (Sorry if this is distracting you from the task at hand ;-) )
Well, to tell you the truth, I just found the Modis Level 1B
Product User's Guide, so I am in the process of *looking*
for distractions just now. :-(
Cheers,
David
P.S. I'm beginning to understand why people who work with
satellite data don't work with dogs underfoot. :-(
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
|
|
|
|
| Re: HDF_Browser Woes [message #53887 is a reply to message #53803] |
Thu, 03 May 2007 11:54 |
Richard Edgar
Messages: 8
Registered: February 2006
|
Junior Member |
|
|
David Fanning wrote:
>> Sorry... my head is spinning..... they don't have a clue what's supposed
>> to be in the file (in any way, shape or form), yet they know that they
>> need to read it????
>
> Clearly you are not on the front lines teaching people
> how to use IDL or your head wouldn't be spinning. (Unless,
> of course, from the inevitable overdose of Prosaic.) But,
> yes, pretty much. They know their professional life
> depends upon it, but they haven't yet learned which poor
> sucker had already done all the hard work and will be
> willing to share it with them.
Well, I would sort of expect them to have a vague idea of what the file
was supposed to contain, even if they don't know _how_ it contains it.
For example, if the HDF file is the output of a hydro calculation, there
are probably going to be three velocities in there somewhere. This would
have me looking for data set names like "v1" or "vx" or "velx" etc. in
the browser. This does rely on the person who created the file doing a
little bit of legwork - a possibly poor assumption.
If all they know about the data is that it's in an HDF file, but have
nary a clue as to what the data might be...... you'll have more luck
extracting meaning from the output of /dev/rand....
(Sorry if this is distracting you from the task at hand ;-) )
Richard
|
|
|
|
| Re: HDF_Browser Woes [message #53888 is a reply to message #53803] |
Thu, 03 May 2007 11:14 |
David Fanning
Messages: 11724
Registered: August 2001
|
Senior Member |
|
|
Richard Edgar writes:
> Sorry... my head is spinning..... they don't have a clue what's supposed
> to be in the file (in any way, shape or form), yet they know that they
> need to read it????
Clearly you are not on the front lines teaching people
how to use IDL or your head wouldn't be spinning. (Unless,
of course, from the inevitable overdose of Prosaic.) But,
yes, pretty much. They know their professional life
depends upon it, but they haven't yet learned which poor
sucker had already done all the hard work and will be
willing to share it with them.
That's, uh, sort of my role in life. :-)
Cheers,
David
P.S. Like everyone else, I'm trying to take the shortcuts,
too. But, unlike everyone else, I have to eventually explain
it to someone, which requires that I actually understand what
I am doing. :-(
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
