Earthdata Forum

Hello,

I processed some MODIS-A files with the standard corrections applied, using a shell script, from L1 to L3.
Sometimes, an image is empty at the end (masks/clouds) so the final file is not saved (l3map).
I wonder :
1) How many pixels / percentage of pixels are required for a file to be saved ?
2) Is there a way to force a file to be saved ?
3) When a file is empty and then deleted after the processing, can we get the information by doing something ? So I can remove it from the list later and avoid processing it again if I need to reprocess the data. I could check if the file exists after the processing, but then I would miss real failure of the processing, that is why I ask.
4) Bonus : How can we change the size of the straylight mask ?

Regards

l3mapgen -h
l3mapgen 2.2.0-V2019.3 (Aug 16 2019 12:46:16)
Usage: l3mapgen argument-list

  This program takes a product (or products if netCDF output) from an L3 bin
  or SMI file, reprojects the data using proj.4 and writes a mapped file in
  the requested output format.

  Return values
    0 = All Good
    1 = Error
    110 = No valid data to map
[...]
   threshold (float) (default=0) = minimum percentage of filled pixels before
        an image is generated
   num_cache (int) (default=500) = number of rows to cache in memory.
   mask_land (boolean) (default=no) = set land pixels to pixel value 254
   land (ifile) (default=$OCDATAROOT/common/landmask_GMT15ARC.nc) = land mask file
   full_latlon (boolean) (default=yes) = write full latitude and longitude arrays (except for SMI)


The return value of 110 should allow you to separate processing errors from files with no filled pixels.

Thanks George, any chance to see an example ?

If you are using bash or a similar shell (dash or zsh), the return value is stored in "$?".   For l3mapgen, you can adapt the following sample script:
#! /bin/bash
#l3mapgen ...
./retval.sh $1
case $? in
0) echo All good from l3mapgen
    ;;
1) echo l3mapgen: error
    echo "insert error processing here ..."
    ;;
110) echo l3mapgen: No valid data to map
   echo "insert no data handling here ... "
   ;;
*) echo Novel return value from l3mapgen.
    echo "Insert novel return value handling ..."
    ;;
esac

To test this script, create retval.sh:#! /bin/bash
exit $1

Make these two scripts executable and try them out:
$ ./retval.sh 0; echo $?
0
$ ./retval.sh 110; echo $?
110
$ ./runner.sh 110
l3mapgen: No valid data to map
insert no data handling here ...
$ ./runner.sh 99
Novel return value from l3mapgen.
Insert novel return value handling ...


Fantastic, thanks again !