- Nothing you should do here, as quite often 4SM shall yield a fairly good estimate.
- Only, if you wish: YES you can.
#LINE_1: build the database, import data, create mask, perform AutoCalibration
The first command line shall get the infos it needs from the image itself.
- it implements -MakePIX, -Import/…, and -AutoCal/… ,
- it uses the shapefiles that have been prepared by the practioner
- or are provided in a tutorial.
- But, the practioner may provide any of them in the command line,
- if he chooses so,
- or if the AutoCal process does not deliver.
- The purpose is to obtain a complete command line,
- specified for the image under study.
In the absence of LsM.shp shapefile, then
- a -LsM... argument must be provided in the command line for the AutoCAL process
- use a -DN... argument to get an estimate of -LsM...
- -DN430/388/5/beach or -DNshp
- run the script,
- search your screen display,
- make a note of the proposed averaged spectrum which was obtained under a circular window with a maximum of 81 pixels: 8U Ls 430 388 /199.0/181.0/165.0
- copy it and insert it in your AutoCal script,
- so that 4SM shall use it, as the LsM.shp shapefile is not available.
In the absence of Lsw.shp or glint.shp shapefiles, then
- a -Lsw... argument must be provided in the command line for the AutoCAL process
- use a -DN... argument to get an estimte of -Lsw...
- -DN185/550/5Lsw or -DNshp
- a -Lw.... argument must also be provided in the command line for the AutoCAL process
- ?Lwred and Lwnir are set to 0 (zero)
- Lwgreen may be set to 1.5 for now
Vegetation.shp is most usefull when using blue band(s)
Optically deep waters : deep.shp
- The AutoCAL process can map optically deep waters to 240 in channel_mSE,
- for this, we need to specify a deep.shp shapefile to that effect.
- Alternatively, we can do that later
- But the open sea is heavily glinted: ours is a difficult task. Here is what we can do :
- get the deglint correlation parameters
- deglint the image
- display channel_22 in OpenEV: BOA radiances less than 6 are optically deep
- recode to 240 all pixels that are less than 6 channel 22 : deglinted green band in channel 22
- ultimately recode some pixels that resisted this process
- More on this at Step 4
In an operational situation, you would
1 - copy an existing command line into your new script tarawa-subset.sh
nice -20 4SM.4.08 -Process -Origin/Arcachon_France
2 - then update it with the specifics of your new image: you just have to change it into
nice -20 ./4SM.8.07 -Process/nosu -Origin/Tarawa_Kiribati
|Once you are acquainted with the use of the commandline, |
- your are advised to proceed that way.
- you can use the script provided and in case of emergency, copy the relevant commandline from this tutorial into your script.
Take control of the -AutoCAL... process
- -makePIX.....may be disabled once the data have been imported and you need to improve th mask mSE
- -import.........may be disabled once the data have been imported and you need to improve th mask mSE
- -extract.........may be specified if you want to impose your conditions
- -deglint.........may be specified if you want to impose your conditions
- -Lsw.............may be specified if Lsw.shp shapefile is not to be used or trusted
- -LsM............may be specified if LsM.shp shapefile is not to be used or trusted
- -LS...............may be specified, although a vlue of LS=25 is assigned by default for all bands
- -AutoCAL... argument has quite a number of parameters Help_AutoCal
- all parameters are optional, as they have been given a default value in 4sm.def textfile
- .../P(p)rint_2_3..........0 That's for me to display details of the clumsy KIKRegressor
- .../M(m)apBPL...............1 That's to map the BPL pixel for pairs of channels
- .../mBL3 or mBPL_3....2 That's for the extraction of calibration data
- .../M(m)akeNewMask..1 Usefull if you're satisfiedd of your mask on a big imag
- .../G(g)etGlint................1 to force a new extraction of glint parameters
- .../C(c)louds..............0 Mapping cloud pixels is not that good at time
- Because you are using the FILE interleaving:
- later during the course of your project, you may want/need to erase any channel
- as 4SM shall re-create any missing channel at first opportunity as blank channel
- before proceeding with the script
- You may want to secure a backup copy of the spacial effect mask mSE though
back to Tarawa tutorial next to Deglint and Investigate your image