Bathymetry and water column correction
at SanLorenzoChannel, Baja california
Image courtesy of the U.S. Geological Survey
7671*7841 30 m pixel size, UTM zone 12
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

scene LC80340432014039LGN00, February 8th 2014
DATE_ACQUIRED = 2014-02-08
    SCENE_CENTER_TIME = 17:48:48.4035141Z

Work done november 2016

GSD 15 m resampled
No sharpening

Ground truth
February 8th 2014    vs   Sonar Depths
RMSE=1.09 m

Sonar Two Days seatruth depths raster
not corrected for tide

15 m GSD
see depth legend

February 8th 2014    vs   DTM

DTM from U. of La Paz, Mexico
resampled to 15 m GSD
see depth legend

Depth residuals ZDTM+0.5m - Z4SM
DTM - February 8th 2014
see legend 

Data and Deglinting

TOA TCC: raw image
logarithmic enhancement

BOA TCC deglinted image
logarithmic enhancement
Glint regressions using SWIR1
No pan-sharpening applied

R2 values are fairly high
15 m resampling does not increase noise


Optical calibration
for the whole image

16U data are scaled to allow for comfortable screen display

Calibration diagram
for the whole image
for bands Blue, Green, Red and NIR


Calibration diagram
for the whole image
for bands Blue, PAN, Red, NIR
  • 0-5m: KBLUE/KGREEN=0.855
    • Jerlov water type OII+0.9
  • 5-13m: clearing progressively to OII+0.3
  • 13-25m: clearing progressively to OIB+0.8
Calibration diagrams are just as good
for a 15m GSD pansharpened image
as it is for original 30 m GSD data

"stratified waters"
actually a fairly complex

Failing to account for it
entails poor control of the optical calibration
and artifacts in the results


"Stratified waters"

Profile Blue location
backdrop is a BOA TCC WCC
The RED and NIR bands exhibit higher deep water radiance where Coastal water type rules:
this is suspended particles load

Ready for modeling

BOA CC WCC normalized
BGR color composite:
  • Blue=Coastal band
  • Green=Green band
  • Red=Blue band

Retrieved depth
see legend

Bottom typing

SAM classified image
see legend for image SAM

Average bottom brightness

see legend for image B


Download results from my GoogleDrive
done november 12th 2016
GSD 15 m Pan-sharpened using Rstudio
gives the same results
does not require smoothing

Contains the following
Channel Descriptor    file="slcOLI_20140208_15mresults.pix";
 1 U8 SAM bottom typing-----------------------------
 2 U8 image B average bottom brightness (0-200)-----
 3 U8 image Z in decimeters-------------------------
 4 U8 WCC reflectance (0-250) at 440.0 nm-----------
 5 U8 WCC reflectance (0-250) at 480.0 nm-----------
 6 U8 WCC reflectance (0-250) at 560.0 nm-----------
 7 U8 WCC reflectance (0-250) at 590.0 nm-----------
 8 U8 WCC reflectance (0-250) at 655.0 nm-----------
 9 U8 WCCnormalized (0-250) at 440.0 nm>B-----------
10 U8 WCCnormalized (0-250) at 560.0 nm>G-----------
11 U8 WCCnormalized (0-250) at 480.0 nm>R-----------
12 S16 Z4SM in centimeters--------------------------
13 S16 ZDTM in centimeters--------------------------
14 S16 ZDTM-Z4SM in centimeters---------------------

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