Announcement: MODISL1DB 1.3 Released

MODISL1DB 1.3 is now available for the MODIS DB community via http://oceancolor.gsfc.nasa.gov/seadas/modisl1db/. MODISL1DB is a MODIS Level-1 Direct Broadcast software package capable of processing Aqua and Terra Level-0 data to Level-1A and Level-1B. This update does not affect the core L1A, GEO, and L1B processing binaries. See below for bug fixes and new features.

If you have already installed a previous version of MODISL1DB, simply install MODISL1DB 1.3 in a new directory and point your DBHOME environment variable to this new directory. If you already have the digital elevation maps, there is no need to re-download them. You can simply move them into the new $DBHOME/data/modis/dem/ directory or create a symbolic link that points to them.

-Best regards from the Ocean Biology Processing Group!-

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MODISL1DB 1.3 CHANGES
=====================

-Minor bug fixes to most of the processing wrapper scripts.

=====================
-Added the modisl1db_benchmarks.bash script which will process a user-
specified Level 0 PDS file to L1A/GEO and then to L1B, calculating the
time required for the processing. See the MODISL1DB benchmarks page.

=====================
-Added use of the curl ftp client (if curl is detected on the host) to
the geolocation processing scripts to allow for listing multiple
directories with one connection. Also tweaked ftp parameters for all
scripts that use ftp. These changes may help to prevent reaching the
OBPG firewall connection limits.

=====================
-Fixed a bug with the write_constructor_file binary that was causing it
to hang when the L0 file had an incomplete scan line.

=====================
-Added the write_5min_gran binary. This utility will split Level 0
granules into separate chunks of length specified by the user.
Executing the command on the UNIX command line prints usage statement:

  USAGE: write_5min_gran MODIS_L0_PDS_file [granule_length] [zulu_start_time]

  granule_length: Time in seconds of each generated granule. (default = 300 sec)

  zulu_start_time: Time of the first packet included in the granule(s). All packets
                         before this time will be ignored. All packets after this time
                         will be included in the output L0 granule(s). If zulu_start_time
                         is not set, the first output granule's filename will be set to the
                         rounded 5 minute interval preceding the time of the first packet.
                         zulu_start_time example: 2006-06-12T16:50:00.00000
                         (default = start time of first packet in L0 granule)

...So the command can be run with:

-only the MODIS_L0_PDS_file argument
-with the MODIS_L0_PDS_file and granule_length arguments
-with all three args in the order specified

The output filename format for each of the chunked granules is
ifile_YYYYDDDHHMM. For example if your input file is "t1.04146.1453.pds",
and you run write_5min_gran without specifying granule_length or
zulu_start_time, then the output filenames will be:

  t1.04146.1453.pds_20041461450
  t1.04146.1453.pds_20041461455

=====================
-Added the fix_L0 binary. This utility will create a new L0 file with L0
packets of the wrong length removed. Executing the command on the UNIX
command line prints usage statement:

  USAGE:     fix_L0 MODIS_L0_PDS_file -1 -1
             OR
                 fix_L0 MODIS_L0_PDS_file taitime_start taitime_stop output_L0_file

  NOTE: Using the '-1 -1' arguments will write information to stdout, including
           valid taitime_start and taitime_stop times for re-input into fix_L0.

=====================
-Added the fix_L0 functionality directly into the Level 0 processing
script modis_L0_to_L1A_GEO.csh. Now if a problem is encountered with
the L0 file, fix_L0 will be run in an attempt to repair the file, and
processing will continue. This feature can be disabled by using the new
modis_L0_to_L1A_GEO.csh "-disable-fix_L0" option:

  -disable-fix_L0 (optional)
   Disable automatic use of the fix_L0 utility if a corrupt or wrong-sized
   Level 0 packet is detected by the write_constructor_file binary, while
   attempting to generate the constructor file. If this option is used and
   such an error is detected, processing will stop. Otherwise, an attempt
   will be made to create a new Level 0 file with the problem packet(s)
   removed, and if successful processing will proceed.

=====================
-Improved MODl1extract to handle high res (HKM and QKM) file extraction.

=====================
-To fix a security hazard, the attitude/ephemeris retrieval mechanism
has been changed and the processing scripts no longer create world
writeable directories under $DBHOME/data/modis/atteph/. This change
does NOT affect users who have write permission for the
$DBHOME/data/modis/atteph/ directory. Users without write permissions
under $DBHOME/data/modis/atteph/ must now set up their own directory
and define the MODIS_ATTEPH variable. In this case, the processing
scripts will check both the user-defined directory as well as
$DBHOME/data/modis/atteph/ for required atteph files.

========================================================================

AFFECTED FILES:

bin/fix_L0
bin/MODl1extract
bin/write_5min_gran
bin/write_constructor_file
scripts/modis_L0_to_L1A_GEO.csh
scripts/modis_L1A_to_GEO.csh
scripts/modis_L1A_to_L1B.csh
scripts/modis_definitive_atteph.csh
scripts/modis_predicted_atteph.csh
scripts/modis_update_luts.csh
scripts/modis_update_utcpole_leapsec.csh
scripts/modisl1db_benchmarks.bash
scripts/modisl1db_env.bash
scripts/modisl1db_env.csh

New Aqua LUTs included:
data/modisa/cal/MYD02_Emissive_LUTs.V5.0.7.13a.hdf
data/modisa/cal/MYD02_QA_LUTs.V5.0.7.13a.hdf
data/modisa/cal/MYD02_Reflective_LUTs.V5.0.7.13a.hdf

New Terra LUTs included:
data/modist/cal/MOD02_Emissive_LUTs.V5.0.6.18.hdf
data/modist/cal/MOD02_QA_LUTs.V5.0.6.18.hdf
data/modist/cal/MOD02_Reflective_LUTs.V5.0.6.18.hdf

hip;
im having troubles trying to get the real information for chlorophyll values ones i download the images to arcview, i have values from 0 to 255 and i dont know how to transform that to real chlorophyll data

i hope you can help me
thanks

Veronica,

Our level 2 files hdf files have metadata that can help you figure out how to convert these values.  In the MODISL1DB bin directory, there is a binary called "ncdump", which can show you the metadata when used properly.  For example, if you are using a file named A2005189180006.L2_LAC, then you would use the following syntax:

$SEADAS/bin/ncdump -h A2005189180006.L2_LAC | more

Then you can look through the metadata and find the SDS for chlor_a(or whatever chlorophyll product you are using).  This will tell you whether the data is stored in float or short format.  It should also provide you with slope and intercept information.  If the data is in float format, you should not need any slope/intercept information, since no conversion is needed.  We have not stored chlorophyll data in short format for quite some time.  So I am not sure how you can be getting short values for chlorophyll.  Nor am I clear on how you are getting chlorophyll values if you are using MODISL1DB, since chlorophyll is not made until level 2 and MODISL1DB only produces up to level 1B.  If you are using SeaDAS to produce level 2 MODIS chlorophyll, it should be in float format, and I would guess that ArcView is somehow converting it to short format.  We do not use ArcView here, so I cannot give you any pointers on how to load the data in as float, but I would assume that you might be able to find that out with a simple Google search.

Regards, Mark