Syntax_DB
-DB or -dB to specify PCI DataBase.pix file to be processed
see Syntax MakePIX

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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
 
 
  •  -dB/tarawa-subset/24_1_0_0/3_1/650_600/714.5_162.54
  •  -DB/database/U8_S16_U16_R32/bands_FirstChRaw/nbRow_nbLin/UTMWest_UTMNorth
  •  -D(d)B/
    • -d     interpretation of the commandline is least    verbose
    • -D    interpretation of the commandline is most    verbose
  • .../tarawa-subset/...
    • database =name of PCIDSK database: 4SM shall add the suffix ".pix"
  •  .../24_1_0_0/...         database structure : number of channels
    • U8   =number of 8U channels
      • let N=number of spectral bands: make U8=4*N+15
    • S16 =number of 16S channels:
      • make S16=1 for Depth in centimeters
      • if seatruth is a DTM in centimeters, make S16=2
    • U16 =number of 16U channels
      • for 16 bits images like Ikonos, QuickBird, Hyperspectral, make U16=N
    • R32 =number of 32R channels
      • make R32=0 as 4SM does not use real 32 bits channels
    • NOTE: channels must be organized in that order in PCI database.pix
    • NOTE: PCI database.pix may be either of BAND or FILE interleaving (CIM syntax)
        
  • .../3_1/..................................bands
    • bands...................number of raw_data_bands
    • FirstChRaw........first channel raw data
  • .../650_600/........................image size
    • nbRow................number of rows/columns in image
    • nbLin..................number of lines       in image
  • .../714.5_162.54/..............UTM coordinates of UL corner of UL pixel: UTM origin of the database
    • West and North in kilometers
No georeferencing pixel
  • suppose no georeferencing pixel is available
  • you would still have to give something, like
    • -DB/PCI/heronETM/31_1_0_0/4_1/1647_1235/0.015_37.035         
    • -Mis/USF/GBR/Landsat/ETM/USF/UTM_16_008/.030_.030/22_NOV_1990          
    • for an image with pixel size 30 m
  • Pixel size is provided in the -MIS... argument
  • You may use -DB (instead of -dB) to display database specifics on screen
  • Minimum channel structure is U8=bands+15+bands+bands+bands...
    • Then optional S16=1
    • Then, if any, U16 channels for U16 raw data like Ikonos or CASI imagery

About the tarawa-subset.pix database structure

-DB/tarawa-subset/27_1S_0s_0s/3_1/650_600/718.069_169.231             
 
  • 27 vs 24?
    • look at the channel descriptor tarawa-subset.mcd textfile
    • there is no fixed maximum number of channels
    •  if you need more for any reason, just increase their number in -D/... argument
      • some of them shall be left unused,
      • like channel 10 for storing bottom typing: does not make sense for a SPOT 1 image which does not have a blue band 
      • like channels 20 and 21
    • or you can use them to contain a copy of some other channel or result
      • a handy aspect of the FILE interleaving
  • so we have 27 U8 channels, but S16 is different, why is 1S?
    • channel_28:
      • is where you store estimated depth in centimeters:
      • requires one S16 channel_28
    • channel_29: if you have a DTM, this is where you store it
      • requires one more S16 channel_29
    • channel_30: is where you store the difference
      • requires one more S16 channel_30
    • for this you change for:
      • -DB/tarawa-subset/27_3S_0s_0s/3_1/650_600/718.069_169.231
    • For a Landsat 8 image like at SanLorenzoChannel:
      • -DB/mbOLI_20160601/40_3S_7S_0s/7_44/4644_3260/568.050_6140.220
      • 40.....U8
      • 3.......S10 for Z4SM, ZDTM, and ZDTM-Z4SM
      • 7.......U16 for copy of raw data
      • 0.......R32
      • 7 bands
      • FirstChRaw in channel_44