[gdal-dev] gdal_edit.py question

[Even Rouault]

Scott,
>
> # add another tif to band 2 and add meta data for it:
> gdalwarp -q -srcband 1 -dstband 2 -t_srs EPSG:4326 src2.tif result.tif

BAND1 is lost at that stage. gdalwarp must override the metadata of the 
output dataset with the one of src2.tif.

Presumably it should instead merge them, using the same logic as what it 
does if you provide several input files in a single gdalwarp operation, 
but this is also questionable if it is always desirable... The hardest 
part would to  name a switch to control that behavior.

A few line GDAL Python script would allow you to automate the merging of 
metadata.


> Another unrelated thing, if I try to add a second band to an existing 
> single band raster using gdalwarp, it throws an error saying the 
> second band doesn't exist. That's understandable, hence gdal_create. 
> The downside is, if you're working with an unknown number of bands, 
> you can't just add it. This would be an extremely useful feature when 
> working with NETCDF, HDF, etc.

A difficult one to implement. That would involve using the AddBand() 
method, but very few drivers support it (GeoTIFF doesn't in particular), 
mostly because of format limitations.

Another way of proceeding is to:

- use warped-vrt for the source 1-band datasets,

- use gdalbuildvrt -separate to create a multi-band VRT from those 
warped VRTs,

- and gdal_translate to convert that to GeoTIFF.

Even

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