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edited Aug 26, 2018 at 9:00

How Is it possible to create .OVR (gdaladdo if possiblelike by gdaladdo) for a grayscale with an alpha bandas smooth as QGIS oversampling feature of raster layer?

I found Hugolpz's tutorial for creating a GeoTIFF that contains grayscale with an alpha band.

# filter the color band, keep greyness of relevant shadows below limit
gdal_calc.py -A ./hillshade.tmp.tif  --outfile=./color_crop.tmp.tif \
    --calc="255*(A>220) +      A*(A<=220)"
# filter the opacity band, keep opacity of relevant shadows below limit
gdal_calc.py -A ./hillshade.tmp.tif  --outfile=./opacity_crop.tmp.tif \
    --calc="  1*(A>220) +(256-A)*(A<=220)"
# gdalbuildvrt -separate ./final.vrt ./color_crop.tmp.tif ./opacity_crop.tmp.tif
# gdal_translate -co COMPRESS=LZW -co ALPHA=YES ./final.vrt ./final_crop.tif

So I wonder if it's posible to have also the .OVR that contains each zoom level's alpha band? I have tried this

gdaladdo -r bilinear -ro -b 1,2 --config COMPRESS_OVERVIEW DEFLATE --config PREDICTOR_OVERVIEW 2 --config ZLEVEL 9 GrayWithAlpha.tif 2 4 8 16 32 64

I found out that if the command lacks of -b 1,2, it doesn't work at all. Then the result still doesn't match the smoothness of QGIS raster layer oversampling feature. Despite beauty of oversampling, it's very very slow.

So I wonder if I can create .OVR that is as smooth as what presented by QGIS oversampling feature?

How to create .OVR (gdaladdo if possible) for a grayscale with an alpha band?

I found Hugolpz's tutorial for creating a GeoTIFF that contains grayscale with an alpha band.

Creating transparent hillshade?

# filter the color band, keep greyness of relevant shadows below limit
gdal_calc.py -A ./hillshade.tmp.tif  --outfile=./color_crop.tmp.tif \
    --calc="255*(A>220) +      A*(A<=220)"
# filter the opacity band, keep opacity of relevant shadows below limit
gdal_calc.py -A ./hillshade.tmp.tif  --outfile=./opacity_crop.tmp.tif \
    --calc="  1*(A>220) +(256-A)*(A<=220)"
# gdalbuildvrt -separate ./final.vrt ./color_crop.tmp.tif ./opacity_crop.tmp.tif
# gdal_translate -co COMPRESS=LZW -co ALPHA=YES ./final.vrt ./final_crop.tif

So I wonder if it's posible to have also the .OVR that contains each zoom level's alpha band?

Is it possible to create .OVR (like by gdaladdo) as smooth as QGIS oversampling feature of raster layer?

I found Hugolpz's tutorial for creating a GeoTIFF that contains grayscale with an alpha band.

Creating transparent hillshade?

# filter the color band, keep greyness of relevant shadows below limit
gdal_calc.py -A ./hillshade.tmp.tif  --outfile=./color_crop.tmp.tif \
    --calc="255*(A>220) +      A*(A<=220)"
# filter the opacity band, keep opacity of relevant shadows below limit
gdal_calc.py -A ./hillshade.tmp.tif  --outfile=./opacity_crop.tmp.tif \
    --calc="  1*(A>220) +(256-A)*(A<=220)"
# gdalbuildvrt -separate ./final.vrt ./color_crop.tmp.tif ./opacity_crop.tmp.tif
# gdal_translate -co COMPRESS=LZW -co ALPHA=YES ./final.vrt ./final_crop.tif

I wonder if it's posible to have also the .OVR that contains each zoom level's alpha band? I have tried this

gdaladdo -r bilinear -ro -b 1,2 --config COMPRESS_OVERVIEW DEFLATE --config PREDICTOR_OVERVIEW 2 --config ZLEVEL 9 GrayWithAlpha.tif 2 4 8 16 32 64

So I wonder if I can create .OVR that is as smooth as what presented by QGIS oversampling feature?

qgis gdal gdaladdo

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asked Aug 25, 2018 at 16:52

sandthorn

How to create .OVR (gdaladdo if possible) for a grayscale with an alpha band?

I found Hugolpz's tutorial for creating a GeoTIFF that contains grayscale with an alpha band.

Creating transparent hillshade?

# filter the color band, keep greyness of relevant shadows below limit
gdal_calc.py -A ./hillshade.tmp.tif  --outfile=./color_crop.tmp.tif \
    --calc="255*(A>220) +      A*(A<=220)"
# filter the opacity band, keep opacity of relevant shadows below limit
gdal_calc.py -A ./hillshade.tmp.tif  --outfile=./opacity_crop.tmp.tif \
    --calc="  1*(A>220) +(256-A)*(A<=220)"
# gdalbuildvrt -separate ./final.vrt ./color_crop.tmp.tif ./opacity_crop.tmp.tif
# gdal_translate -co COMPRESS=LZW -co ALPHA=YES ./final.vrt ./final_crop.tif

So I wonder if it's posible to have also the .OVR that contains each zoom level's alpha band?

gdal gdaladdo