Blend mask and NullValue becomes black?

[arno]

Hi all,

I'm having a small issue with resample. I am trying to compile a photo scenery that has a blendmask as well. So I use the INF file below. But when I set the NullValue so that a zero in the blend mask is considered to be NULL, I do get black output in the area that should be masked (see the screenshot below). What am I doing wrong here?

[Source]
Type = MultiSource
NumberOfSources = 2
[Source1]
Type                = GeoTIFF
SourceDir           = "."
SourceFile          = "img_0.tif"
Layer               = Imagery
Variation           = Day
Channel_BlendMask   = 2.0
NullValue           = ,,,,0
[Source2]
Type                = GeoTIFF
SourceDir           = "."
SourceFile          = "bmask_0.tif"
Layer               = None
SamplingMethod      = Gaussian
nBands              = 1
SampleType          = UINT8
[Destination]
DestDir             = "C:\dev\astofra_vearth\Tests\data\scenProc\out"
DestBaseFileName    = "resample_simple_mask"
DestFileType        = BGL
LOD                 = Auto
CompressionQuality  = 85

 

[arno]

Hi,

Of course just after posting here I found it. I needed to add the NullValue in the blend mask as well, see the INF below:

[Source]
Type = MultiSource
NumberOfSources = 2
[Source1]
Type                = GeoTIFF
SourceDir           = "."
SourceFile          = "img_0.tif"
Layer               = Imagery
Variation           = Day
Channel_BlendMask   = 2.0
NullValue           = ,,,,0
[Source2]
Type                = GeoTIFF
SourceDir           = "."
SourceFile          = "bmask_0.tif"
Layer               = None
SamplingMethod      = Gaussian
nBands              = 1
SampleType          = UINT8
NullValue           = 0
[Destination]
DestDir             = "C:\dev\astofra_vearth\Tests\data\scenProc\out"
DestBaseFileName    = "resample_simple_mask"
DestFileType        = BGL
LOD                 = Auto
CompressionQuality  = 85

 

[rhumbaflappy]

You can brag you've forgotten more than most people will ever know.

 

[GaryGB]

Indeed, there are a number of 'tricks and traps' one must recall and use when combining a Blend Mask with a *.INF NullValue parameter value to either specify removal of a particular color, or to assign a NO_DATA attribute to pixel arrays.

For most FS Developers those permutations are rather daunting (and AFAIK, most apparently do not attempt that process).

For those that wish to try doing what Arno is testing, here is a link to some pertinent info:

https://www.fsdeveloper.com/forum/threads/changing-null-value-in-sbuilderx-inf-file.427714/

BTW: Arno, do you also edit the default BGL compression level from 85 back up to 90 percent as Holger does to minimize banding in gradient / feathered transitions of water areas, or do you use Floyd-Steinberg dithering on the 8-Bit grayscale TIFF BlendMask ?

GaryGB