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ausseabed / qax

Quality Assurance Tool for Multibeam Echosounder (MBES) data
https://www.ausseabed.gov.au/QAX
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Proposal: Change QAX MBES Grid Checks band order #16

Open lachlanhurst opened 2 years ago

lachlanhurst commented 2 years ago

The QAX Grid Transformer generates multi-band GeoTIFFs with three bands in the following order; density, depth, and uncertainty. Checks within the MBES Grid Checks and Finder Grid Checks plugins expect bands to be in this order.

Teledyne CARIS expects depth to be the first band within GeoTIFFs; therefore when a QAX Grid Transformer generated GeoTIFF is loaded into CARIS the density layer is interpreted as depth. This is not an ideal situation. The ordering currently used by QAX was chosen arbitrarily; changes to this ordering should not adversely impact other 3rd party tools.

This proposal will change the band ordering of GeoTIFFs created by QAX to be; depth, density, and uncertainty. The MBES GC and Finder GC plugins will be updated to support this new ordering. To support backward compatibility, these plugins will look to identify bands by their names (already included in QAX generated GeoTIFFs), and if no names are present then the revised band ordering will be used.

lachlanhurst commented 2 years ago

GDAL info output from a QAX generated GeoTIFF showing the band ordering and embedded names (using description field)

Band 1 Block=5110x1 Type=Float32, ColorInterp=Gray
  Description = Density
  NoData Value=3.4028234663852886e+38
  Metadata:
    Band_Direction=NAP
    Band_Name=Density
Band 2 Block=5110x1 Type=Float32, ColorInterp=Undefined
  Description = Depth
  NoData Value=3.4028234663852886e+38
  Metadata:
    Band_Direction=Height
    Band_Name=Depth
Band 3 Block=5110x1 Type=Float32, ColorInterp=Undefined
  Description = Uncertainty
  NoData Value=3.4028234663852886e+38
  Metadata:
    Band_Direction=NAP
    Band_Name=Uncertainty
giumas commented 2 years ago

Why not depth, uncertainty and density? Furthermore, for BAG files, the density layer is optional.

giumas commented 2 years ago

+1

lachlanhurst commented 2 years ago

Why not depth, uncertainty and density?

I'm happy with this order too, especially if there is some reasoning behind it?

lachlanhurst commented 2 years ago

Furthermore, for BAG files, the density layer is optional.

The bigger issue is that QAX grid checks require all three bands, tracking this one separately under #20 .