Bathymetry and water column correction
LANDSAT 8 OLIP 
at Freeport, Bahamas
Image courtesy of the U.S. Geological Survey
7671*7841 30 m pixel size, UTM zone 18


 
Using the Panchromatic band for water column correction
to derive water depth and spectral bottom signature:

Landsat 8 OLIP bandset used for this work
Purple=1Blue=2Green=3PAN=4Red=5NIR=6 and SWIR1=7

home


 
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
 
So
I keep digging
until suitable data
become available
 

scene LC80140422014363LGN00, December 29th 2014
this scene is continued southwards at 
fpoli2-20141229  (same date)
Work done october 2016



Data and Deglinting

TOA TCC: raw image
logaritmmic enhancement

BOA TCC deglinted image
logaritmmic enhancement
note a few whitings



Optical calibration
16U data are scaled to allow for comfortable screen display
OPTIMIZED CALIBRATION

Calibration diagram for the whole scene
for bands Blue, Green, Red and NIR
OPTIMIZED CALIBRATION

Calibration diagram for the whole scene
for bands Coastal, PAN, Red and NIR




Ready for modeling
No Smoothing

BOA TCC: water column corrected
whitings look pinkish

Retrieved depth
see legend

 



Bottom typing

SAM classified image
see legend for SAM

Average bottom brightness

this scene is continued southwards
at 
fpoli2-20141229  (same date)