On mercredi 12 avril 2017 13:23:06 CEST Stephen Woodbridge wrote: > Hi all, > > I'm reworking my code dealing with NAIP imagery that has R, G, B, IR > bands, and I generate a mask band when reprojecting it. I also have the > option to generate another computed band based on a sobel operator. > > In the past, I separated them R, G, B, mask into jpeg ycbcr compressed > tiff and had separate files for the IR, and the sobel data and used a > VRT file to pull all these together into a single image for additional > processing. > > Ideally, I would like to have one file, rather than 4 files (RGB, IR, > sobel, and the VRT) because over large areas the management of all these > files is a pain. Also when displaying and working with large areas I > need to mosaic the images into a seemless area using a vrt file or > tileindex. > > I need a way to display the various bands, and mapserver is my tool of > choice, but I probably need to be able to display them via qgis also, > which I have not experience with but reading older posts, I might need > to create a vrt file. In mapserver I can select bands using PROCESSING > options on layers. > > Questions? > > 1. Does it make sense to try and do this with one tiff with 6 bands? > 2. What would be the best workflow for doing this? I'm thinking > something like: > > # remove any collar > nearblack -co TILED=YES -of GTiff -nb 0 -near 0 -setmask -q -o temp1.tif > doqq.tif > > # warp to EPSG:4326 (does -dstalpha convert mask band to an alpha band?)
Yes > gdalwarp -t_srs EPSG:4326 -dstalpha -co TILED=YES temp1.tif rgba.tif > > # make sobel gray scale single band image > makesobel.py rgba.tif sobel.tif > > # create a temp.vrt file with bands R, G, B, Alpha|mask, IR, sobel > > # and finally build a tif using the temp.vrt > # I'm not sure what is the best way build the final tif given the mask > # and whether I should use gdalwarp or gdal_translate for this step > gdal_translate -co TILED=YES -co JPEG_QUALITY=90 -co COMPRESS=JPEG > --CONFIG GDAL_TIFF_INTERNAL_MASK YES temp.vrt final.tif --> This will only work as intended if there's a mask band identified as a mask and not an alpha band in the VRT. > > # and build overviews > gdaladdo -clean -r average final.tif 2 4 8 16 32 64 128 > > I'm not clear on how the mask band or alpha channel(band?) interacts > with the various commands at each step in the workflow. > > Thanks, > -Steve > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/gdal-dev -- Spatialys - Geospatial professional services http://www.spatialys.com
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