Caicos Combined Depth
Depth results for a series of co-registered images
are averaged to produce a final DTM

combined depth for 11 bad SLCOFF images
return to main Caicos page

 


 
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
 



             
                                                                     

Since 2003, ETM images have SLCOFF gaps
visible here on the image of Computed Depth
for /ETM_009_045_2010-04-27
 

It is possible
to merge the results
obtained with a series of SLCOFF images,
in order to generate an acceptable DTM.


In such a time series of images,
the tide difference,
the presence of clouds,
and  the many gaps in the image

are conveniently wiped
out of the final results.


23 images CaicosCZ_UTM19.opf



ALL 23 images

 

16 images CaicosCZ_UTM19_SLCOFF.opf



16 images SLC OFF



profile tide 23 images
 


profile tide on 16 images SLCOFF


profile black, 23 images
 
 

Standard deviation on 16 images SLCOFF

profile red 23 images
 
 

NN on 16 images SLCOFF


profile_green 23 images
 
 

profile_green 16 images SLCOFF

CaicosCZ_UTM19_details.txt
 

CaicosCZ_UTM19_details.txt
at pixel -RL2760/2356
Final Average Depth is 6.76+-0.92m (N=15/23)
at pixel -RL2760/2356
Final Average Depth is 6.71+-0.30m (N=8/16)
at pixel -RL3070/2531
Final Average Depth is 10.80+-3.30m (N=20/23)
at pixel -RL3070/2531
Final Average Depth is 10.93+-2.81m (N=13/16)
at pixel -RL2460/1390
Final Average Depth is 0.84+-0.99m (N=17/23)
at pixel -RL2460/1390
Final Average Depth is 0.89+-0.67m (N=10/16)