|
|
| The 4SM_LUT approach using Landsat 8 data, 2021 A time series of Landsat 8 scenes at La Paz, Mexico, 2016 HICO at LSI, Bahamas Princess Cays Panchromatic PAN-sharpened CASI HYPERION WV2 OLI 4SM vs ALUT 4SM vs DigitalGlobe From raw data to bottom typing: it works 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 |
Users of Geomatica, ENVI, Erdas, TNTmips, ERmapper, Ilwis, Idrisi, etc,  no sweat: I only use open source      |
| Leave difficult cases to semi-analytical methods! Further to Lyzenga et al's empirical ratio method: water volume reflectance is an important variable. No need for atmospheric correction. Uses Jerlov's data for optical calibration. | Landsat 8 See work may2016 at LaParguera, Puerto Rico See work July2016 at Caicos Bank, Bahamas | Just use a X86 or AMD64 laptop running Linux.  From importing raw data to formating deliverables in one single 4SM executable code. Uses a bash command line, focussed on productivity. |
| Users of Lyzenga's or Stumpf et al's methods,  please be advised on the cost of dispensing with water volume reflectance. |  | 4SM demonstration: 40 times faster than best ALLUT process on the same CASI image. |
Albert & Mobley's analytical model (2003) is used commercially by EOMAP and PROTEUS. .... BOA |
| HELP! For operational purpose, we need a way out: the simplified shallow water Radiative Transfer Equation. 1989  BOA Philpot 1994  BOA Maritorena et alThese BOA models require formal atmospheric correction. |
Following Lyzenga, Maritorena, Jerlov and Kirk, passive optical bathymetry is operational and practical |
 "operates" the simplified shallow water RTE. Being a "ratio method", it works for TOA radiance as well. |
| 4SM only uses the satellite image: no atmospheric correction or field data required. Yields both retrieved depth and water column corrected spectral radiance, ready for bottom typing. |
  No need for field data to retrieve depth in meters just determine Ki/Kj for wavelengths i and j (Lyzenga), then derive spectral K in m-1 for all visible bands (Kirk). |
| From 2009 to 2015, I got paid good money by the same customer for several demanding projects using Landsat and WV2 Tanzania, Bahamas, Bahrain, Western Australia, Seychelles, Red Sea, and the UAE   |
| Oct 2016: a time series of Landsat 8 MULTI+PAN scenes at SanLorenzoChannel, Baja California | read more |
| Oct 2016: a time series of Landsat 8 MULTI+PAN scenes at LSI, Bahamas | read more |
| Jul 2016: a time series of Landsat 8 MULTI+PAN scenes at Caicos, Bahamas | read more |
| May 2016: a Landsat 8 MULTI+PAN scene at La Parguera, Puerto Rico | read more |
| Feb 2016: a WV2 MULTI+PAN scene at Gulf of Laganas, Greece | read more |
| Mar 2015: a PAN-sharpened QB scene at Shiraho Reef, Japan | read more |
| Jan 2015: HICO data | read more |
| Sep 2014: generic optical calibration of the Panchromatic band | read more |
| May 2014: 4SM demonstration using CASI data at Heron Island | read more |
| May 2014: ETM over Florida Bay: water types from Coastal4 to OIB | read more |
| Feb 2014: HYPERION data at La Parguera Nature Reserve, Puerto Rico | read more |
| Feb 2014: further to Lyzenga's method, and how 4SM adds to it | read more |
| Jan 2014: Landsat 8 MULTI+PAN at Dry Tortugas National Park, Florida keys, USA, with seatruth LIDAR DTM | read more |
| Dec 2013: CASI data at Heron Island, GBR, Australia, with seatruth DTM | read more |
| Nov 2013: the "PANchromatic solution" for shallow water column correction using 4SM | read more |
| Nov 2013: water volume reflectance and reflectance of the brightest shallow substrates in coral reeef | read more |
