4SM CASI porquerolles french riviera

go to bottom Typing

-WL467/508/523/535/544/554/565/574/585/595/644/845 in nanometers
Unfortunately, this dataset lacks bands in the red-to-green region of the solar spectrum.
Only one blue band.
This does not help for an optimal deglinting, and also for calibrating/modeling.

Lucky that we have one NIR band!

The best calibration of CASI data I have seen to-date, april 2008 with 4SM.2.06.

Lots of clean bright sands here, at all depths.
I wish I was given the chance of a proper 4SM work on this dataset:
starting from raw flightlines, myself on my own machine.

	The best calibration of CASI data in town! See that wavelengths adopted for this bandset fit well an intermediate curve of Jerlov's classification of marine waters: Jerlov's water type was ~OII+0.28 in october 2000
	Path radiance: see in particular that it is very clear how the atmpspheric path radiance is determined by use of the SoilsLine by NIR here.
	The worst mosaic in town! This image was not corrected for limb brightening, nor for variable illumination, nor for bad rows, nor for fancy ILS pixels.
	The worst mosaic in town! Deglinting-Smoothing can't make this image worthy of shallow water work, although this marine park sanctuary site was quite a bit of an opportunity. Certainly worth a proper pre-processing/mosaicking: I wish I was given the chance of a proper 4SM work on this dataset, starting from raw flightlines, myself on my own machine. There is a lot to learn from such a project, both for data collection/pre-processing and for 4SM processing.

Cleaned_Equalized_Deglinted image Some cleaning/preprocessing of raw data was really worth the pain. BUT REMEMBER GARBAGE IN ==> GARBAGE OUT anyway.	Color Composite of Normalized Spectral Bottom Reflectance According to Jaubert et al., one large and well defined bright green bed of Caulerpa taxifolia lies at a former wreckage place.
Computed Depth image_Z250 image_Z250 modal filtered image_wZ: depth is computed down to ~15 m	Average Bottom Reflectance image_B mostly extermely dark bottoms
Color composite of the "water column corrected" image_LBS like if at low tide Mostly very dark bottoms: this site is said to have a lot of seaweeds	Histogram equalization of image_LBS helps to see throuh and its normalization helps further
Negative bottom contrast ... Negative bottom contrast abound over very dark bottoms here at 467 nm	... a real challenge for modeling! Negative bottom contrast abound over very dark bottoms here at 523 nm

Now we can run

a bottom type classification in 4SM
as of april 2008
This was done in 4SM without any access to seatruth,
including a final modal filtering

Under such adverse conditions,
the equalization has been a real challenge.

Too bad the deglinting was not able
to clean properly the heavy sun glint.

Flying into or away from the sun
would have been advisable indeed
in view of shallow water work!

23 bottom types are mapped:
mostly three famillies of bottom types:

Sands with vegetation: types 6 to 11
"green" vegetation: types 12 and 13
"brown" vegetation: types 14 to 23

STATISTICS OF
SHALLOW BOTTOM TYPING
BOA radiance 0-200
on Tue Apr 29 06:21:54 2008

Type_0 is Land pixel

Type_1 is Unclassified Shallow pixel
Type_2 is Optically Deep water pixel
Type_3 is No Data pixel
Type_4 is Wave Breaker pixel
Type_5 is Cloud/Shadow pixel

1.05% as type_1, i.e. Shallow_pixel_NOT_Classified

2.27% as type_6   SIG 163.7 168.5 179.6 167.7 166.6 164.2 165.0 168.6 163.4 167.1 169.7 167.6
BGSL_168 SD_5.3    STD 12.3   8.8   8.1   7.9   8.2   8.0   8.1   8.8   7.8   9.7   9.8   9.4

3.41% as type_7   SIG 145.6 155.3 170.4 162.0 163.2 162.5 164.6 170.4 160.3 159.8 148.3 155.9
BGSL_156 SD_2.5    STD   3.6   3.7   4.3   4.1   3.9   4.1   3.8   4.8   4.0   4.0   3.7   3.6

5.33% as type_8   SIG 89.7 109.4 118.0 105.5 103.5 100.3 101.3 105.5 102.4 105.5 97.0 102.0
BGSL_102 SD_3.3    STD   3.5   3.7   3.8   3.3   3.2   3.0   3.0   3.1   3.2   3.3   3.8   3.5

1.90% as type_9   SIG 74.6 95.0 103.6 93.2 92.5 89.8 91.5 94.8 91.2 92.0 81.8 88.2
BGSL_88 SD_3.5    STD   3.3   3.3   3.5   3.1   3.0   2.9   2.9   2.8   2.9   3.1   3.4   3.1

2.88% as type_10 SIG 67.1 83.9 92.3 83.4 82.4 80.3 81.4 86.2 82.5 83.6 72.9 78.6
BGSL_79 SD_4.1    STD   3.4   3.6   3.8   3.3   3.0   3.0   3.0   3.2   3.1   3.3   3.4   3.4

7.54% as type_11 SIG 44.9 51.2 57.6 55.8 57.8 57.6 60.4 61.3 55.3 51.8 47.6 51.4
BGSL_51 SD_8.5    STD   3.3   4.2   4.8   4.6   4.6   4.8   4.8   4.9   4.5   4.3   3.7   4.0

8.75% as type_12 SIG 27.7 25.3 28.6 27.4 28.4 28.4 29.9 31.7 28.7 28.3 26.1 27.3
BGSL_27 SD_7.7    STD   1.6   2.1   2.3   2.2   2.3   2.3   2.3   2.4   2.3   2.1   1.8   2.0

3.81% as type_13 SIG 16.0 18.6 21.1 18.4 19.4 19.2 20.8 21.8 20.1 19.6 16.2 18.1
BGSL_18 SD_5.4    STD   1.0   1.0   1.1   1.0   1.0   0.9   1.0   1.0   1.0   0.9   1.0   1.0

13.31% as type_14 SIG 39.3 32.3 35.2 32.9 34.3 33.3 36.5 36.0 35.2 35.5 35.4 35.4
BGSL_35 SD_12.5   STD   4.5   4.4   4.5   4.1   4.4   4.5   4.9   4.5   4.7   4.4   4.4   4.4

18.68% as type_15 SIG 22.0 19.0 20.0 16.7 16.8 16.2 16.9 18.1 17.1 18.7 19.9 19.5
BGSL_20 SD_14.5   STD   3.3   2.9   3.2   2.9   2.7   2.5   2.4   2.7   2.8   3.2   2.8   3.0

8.09% as type_16 SIG 18.6 11.7 14.2 13.3 15.1 13.1 17.1 14.7 15.0 15.0 15.0 15.0
BGSL_15 SD_6.6    STD   1.4   0.9   0.9   0.9   1.0   0.9   1.2   0.9   0.9   0.9   0.9   0.9

8.19% as type_17 SIG 16.8   9.4 11.4 10.7 11.8 11.1 13.7 12.9 12.7 12.7 12.7 12.7
BGSL_13 SD_5.6    STD   0.8   0.7   0.8   0.7   0.7   0.7   0.6   0.7   0.7   0.7   0.7   0.7

3.05% as type_18 SIG   9.1   4.5   5.1   6.2   6.4   5.8   8.9   9.4   8.3   4.4   6.6   6.6
BGSL_7   SD_12.1   STD   0.8   0.8   0.9   0.7   0.8   0.7   0.8   0.8   1.0   0.8   0.8   0.8

5.76% as type_19 SIG 13.2   0.8   3.1   2.7   5.1   4.1   8.1   7.2   3.9   6.1   6.1   6.1
BGSL_6   SD_17.4   STD   1.8   0.5   0.9   0.9   1.2   1.0   1.5   1.1   1.0   1.1   1.1   1.1

4.18% as type_20 SIG   8.2   2.0   3.3   3.7   5.1   5.0   7.4   7.4   5.3   3.3   5.0   5.0
BGSL_5   SD_27.5   STD   1.3   1.2   1.6   1.4   1.5   1.5   1.7   1.6   1.5   1.4   1.3   1.3

1.09% as type_21 SIG   4.4   3.1   4.7   2.6   4.3   3.7   6.2   5.4   3.8   1.1   3.9   3.9
BGSL_4   SD_10.7   STD   0.2   0.4   0.5   0.4   0.4   0.4   0.5   0.5   0.6   0.5   0.3   0.3

0.39% as type_22 SIG   4.3   3.5   3.9   1.5   2.9   2.1   4.3   3.4   3.4   3.4   3.4   3.4
BGSL_3   SD_8.3    STD   0.2   0.2   0.3   0.3   0.3   0.2   0.2   0.5   0.5   0.5   0.5   0.5

0.33% as type_23 SIG   9.3   0.5   0.4   2.2   2.3   1.3   4.3   4.9   3.4   4.0   4.0   4.0
BGSL_4   SD_5.6    STD   0.4   0.2   0.3   0.2   0.3   0.3   0.2   0.3   0.3   0.1   0.1   0.1


Type 6	Type 7	Type 8	Type 9	Type 10	Type 11

Type 12	Type 13			23 bottom type signatures are extracted from select areas of interest of the "water column corrected" image

Type 14	Type 16	Type 18	Type 20	Type 22	Type 23