| Re: HDF_SD_GETACCESS: No content in variable, error [message #71851 is a reply to message #71782] |
Fri, 23 July 2010 01:11  |
aa8533
Messages: 8
Registered: July 2010
|
Junior Member |
|
|
On Jul 22, 7:54 am, Dave Poreh <d.po...@gmail.com> wrote:
> On Jul 21, 9:38 am, David Fanning <n...@dfanning.com> wrote:
>
>
>
>
>
>> aa8533 writes:
>>> Hi - I'm trying to make a program which automatically runs through
>>> 100s of images (MODIS Fire data) and extracts data at a particular
>>> point. The program works fine where there is data to extract (in the
>>> case below, when there is data in FP_Sample) but halts for an image
>>> where there is none with message "Array dimensions must be greater
>>> than 0".
>
>>> Extract of code is:
>
>>> sd=hdf_sd_start(fileName)
>>> index=hdf_sd_nametoindex(sd,'FP_sample')
>>> sds=hdf_sd_select(sd,index)
>>> hdf_sd_getdata,sds,sample <------------------ Halts with message
>>> here
>
>>> Is there a way to test the size of the variable (in this case Sample)
>>> and if, say it's -1 (no data) then skip the last line of this code?
>
>> I opened each of the two files you sent me up in my
>> NCDF_Browser program and I could immediately see that
>> FP_sample in the file that causes the problem has
>> a dimension of 0. Obviously, nothing is there, even
>> though the variable has been defined in the file!
>
>> To look for this possibility (I have modified my own
>> code in ncdf_data__define.pro and it will be on my
>> web page shortly) you will have to check for a zero
>> length dimension:
>
>> sd=hdf_sd_start(fileName)
>> index=hdf_sd_nametoindex(sd,'FP_sample')
>> sds=hdf_sd_select(sd,index)
>> HDF_SD_GetInfo, sds, DIMS=dims
>> IF dims[0] NE 0 THEN BEGIN
>> hdf_sd_getdata,sds,sample
>> ENDIF
>
>> I notice that every variable in that particular data file
>> has a dimension of 0. That is one very sick puppy! :-)
>
>> 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.")
>
> That is a wise solution. You are the man David!
> Cheers
> Dave
David, thank you so much, that works fine now, saving me hours of
frustration
I appreciate it.
Matt
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
