[gdal-dev] 2D multiband to 3D MULTIDIM results in duplicated "x" dimension

[Even Rouault]

Michael,

fixed per https://github.com/OSGeo/gdal/pull/11005

Otherwise just do "gdal_translate Rlogo.png Rlogo.zarr -of Zarr" . By 
default the Zarr driver translates GDAL bands as the Z dimension, unless 
you specify the SINGLE_ARRAY=NO creation option, in which case it will 
create a Zarr array per band (so a different default as the netCDF driver).

Even

Le 14/10/2024 à 14:10, Michael Sumner via gdal-dev a écrit :
> Possibly this is a fool's errand ...
>
> I want to be able to cast an RGBA file as a Zarr, so first to cast as 
> multidim I tried the CreateCopy route with NetCDF and I see dimension 
> "x" repeated, with "y" missing. (I'm using an external file as the 
> existing test PNG files are square in shape).
>
> from osgeo import gdal
>
> ## PNG source is 100x76 * 4 bands
> f = 
> "/vsicurl/https://github.com/cran/png/blob/master/inst/img/Rlogo.png?raw=true"
> src_ds = gdal.Open(f)
>
> ## set NetCDF metadata to make Bands 0,1,2,3 a Z dimension
> size_z = 4
> src_ds.SetMetadataItem('NETCDF_DIM_EXTRA', '{Z}')
> src_ds.SetMetadataItem('NETCDF_DIM_Z_DEF', f"{{{size_z},4}}")
> src_ds.SetMetadataItem('NETCDF_DIM_Z_VALUES', '{1.25,2.50}')
> src_ds.SetMetadataItem('Z#axis', 'Z')
>
> # Create netCDF file
> gdal.GetDriverByName('netCDF').CreateCopy('out.nc <http://out.nc>', 
> src_ds)
>
> ## investigate shape as a mdim
> ds = gdal.OpenEx("out.nc <http://out.nc>",  gdal.OF_MULTIDIM_RASTER)
> rootGroup = ds.GetRootGroup()
> var = rootGroup.OpenMDArray("Band1")
>
> ## we ended up with x,x,Z
> [dim.GetSize() for  dim in  var.GetDimensions()]
> #[4, 100, 100]
>
>
> That looks like a bug?
>
> And, is there a better way to go about this? PNG->ZARR is my target, 
> I'm fine with programmatic creation of NetCDF, but this could be quite 
> handy as a two-step conversion from pseudo-3D to actual 3D via the cli 
> with "gdal_translate -mo ...". (This is not for real work fwiw, just 
> for me programming at the edges of Zarr, with examples that are clear 
> in visual terms).
>
> Cheers, Mike
>
>
>
>
> -- 
> Michael Sumner
> Research Software Engineer
> Australian Antarctic Division
> Hobart, Australia
> e-mail: mdsumner at gmail.com
>
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