Optical calibration, bathymetry, water column correction and bottom typing of shallow marine areas, using passive remote sensing imageries

busy? see 4SM slides
4SM cookbook: teach yourself 4SM

4SM errors 
4SM conclusions

1 - NO NEED for field data, nor for atmospheric correction
2 - this is demonstrated in this website, using a variety of hyper/multi spectral data
Requirements are
1 - homogeneous water body and atmosphere
2 - some coverage of optically deep water
3 - some coverage of dry land
Problems are
1 - the precision on estimated depth is found wanting, because the noise-equivalent change in radiance  of accessible data is too high for shallow water column correction work 
2 - radiance data should be preprocessed by the provider at level 1 in order to improve S/N ratio
3 - exponential decay: the deeper/darker the bottom, the poorer the performances
I keep digging
until suitable data
become available
Your comments are invited                            See you on 4SM blog
Teach yourself 4SM in just one week -well, sort of!
Download free tutorial zipfiles,
complete with a 4SM executable code, the image, and detailed step by step tutorial

Is there is a huge market for shallow water optical modeling
4SM download: free tutorials
Further your training for a price
Then what?
There is a huge market for shallow water optical modeling:
just google satellite derived bathymetry
  • For free: you can get started on your own using my website:
    • the 4SM executable code is there. All you need is a Linux X86 or AMD64 PC workstation and Openev, some targeted reading, and ... suitable commitment and time.
    • There is even one option in 4SM for using NOAA's method (with no need, in 4SM, for atmospheric correction or field data), once the calibration has been achieved properly, if this is what you really want to test.
  • For free: then you can work on any of your own images,  provided it is small enough:
    • ?calibration
    • deglinting-smoothing
    • sea truth,
    • profiling
    • final modeling
    • bottom typing
  • For a price: then you can process your own images yourself to final output on the whole image
    • ?it is just a question for me to allow it through the license key system, imagewise
    • you run 4SM on your image to get the Required_LicenseKey for tht image
    • you e-mail me the Required_LicenseKey
    • and I e-mail you back a CommandLine_Licensekey
      • that you will include inside the 4SM commandline script
      • in order to enable the unrestricted processing your full image.
    • Whether I get paid for that Command Line_License key remains to be seen,
      • as what I want most at present is that 4SM be actually used and keeps improving:
    • I would prefer that an agreement to cover this aspect be arranged as you see fit.
    • then you should become a super user of 4SM, so that you'll enjoy unrestricted priviledges on your own machine
Teach yourself 4SM in just one week -well, sort of!
Download free tutorial zipfiles,
complete with a 4SM executable code, the image, and detailed step by step tutorial

4SM Workstation  and work environment


Prepare your work environment
Here is how 4SM HELP works
  • Or you can relocate /Full/Path/Of/RSP.4SM anywhere on your machine or network
    • and place a -URL/file:///Full/Path/Of/RSP.4SM in your commandline
  • Beware though that this website is constantly improved,
    • so you should also get a complete update regularly.

Experience the learning curve
Sorry: I'm constantly improving, so you might experience frustration with the code.
So don't hesitate to interact with me: I'll do my best to satisfy you.

First, you'll need to familiarize with atmospheric and underwater optics.
Then, please start with the tarawa tutorial, then arcachon, then tmnov, then negril.
Then you can venture into working on your own 4 bands images, like TM, ETM, Ikonos, QuickBird, ....
Then only, you'll be ready for the big experience with hyperspectral data. 

Resources to download
  • Content of each download : each download contains4SM executable code
    • FWTools-linux-2.0.6.tar.gz for you to install OpenEV
    • 4sm.calls/      a directory with GMT and shp2text executables, and OpenEV pseudocolor palets
    • data/               a directory with the raw image data
    • various shapefiles
    • an OpenEV project file
    • a bash script file
  • Executables : Make sure they are all executables
    • " chmod -R a+rwx    4SM.4.08   4sm.calls/* "
  • Current  version of 4SM executable code
    • As from now, I'll use 4SM to mean the current executable code (like 4SM.4.08)

  • enter "./4SM" at the prompt of your terminal
  • this connects to
    • your local mirror copy the 4SM website (see above)
    • or to the original website on the Internet
  • then checks the following (see system calls)
    • openev...................................check that OpenEV works well
    • gedit..............................check that 4SM's default texteditor is OK; tab width is set at 8 in my gedit's preference
    • gv.................................check that 4SM's default PostScript viewer is OK
    • shptext.........................check that shp2text works fine
    • GMT executables.........check that GMT executables work fine
      • gmtset
      • psbasemap
      • psxy
      • pstxt
      • psscale
    • chrome...........................check that 4SM's default browser is OK
    • whoami and cpuid......finds out your username and whether you are a superuser
  • and welcomes you with access to 4SM HELP services
  • Please start with this detailed introductory SPOT 1 study case.
  • It demonstrates that the simplified radiative transfer equation
    • in its operational form Ls=Lsw+(LsB-Lsw)/exp(2K*Z)
    • does behave in a linear manner across the visible spectrum.
  • A nice 3-band case with a lot of skyglint , beautiful modeling using the NIR band.
  • Fairly clear waters in Equatorial Pacific.
Caicos TM tutorial
Negril TM tutorial
Further your training 
(for a price if/when I get organized for that)
big and real life images, complete with 4SM executable code, command line, and ancillary files


for 16U images (Ikonos and CASI) the raw data channels are void, for sake of copyright.
If you hold the image, then you can import the 16U data and run a full processing.
For TM and ETM images, the raw data is included.

Then what: any license?

All functionalities are enabled in 4SM executable,
but modeling is limited to a small sub-window
or result channels are chequered
unless your image is square and small enough
or its licensekey is included in 4SM.
This means that you can run your calibration,
and sea truth evaluation using the RegressZZ module,
ahead of any actual modeling of your image.
Then if/when satisfied with your Calibration and Command Line,
you shall have to purchase some kind of license for full modeling of your image.