[Gdal-dev] Datatype of bands
mhanson at photon.com
Fri Aug 18 14:53:25 EDT 2006
Hi, I have a couple questions regarding the data type of bands in a single dataset. Each spectral band in a file could potentially have a different datatype.
1) Is there an easy way to retrieve the smallest data type that can hold the values across all bands, or only by iterating through with GetRasterband()->GetRasterDataType() and calls to GDALDataTypeUnion()?
2) It looks like GDAL cannot *create* a file with varying data types across spectral bands unless it is done with first a Create(), then using AddBands() to add each band individually. But AddBands() isn't supported by all data formats. I haven't been able to find a list of formats that support AddBand...did I miss it?
3) Not so much a GDAL question, but I was wondering how common users out there have found different datatypes vs. bands to be. I don't think it's all that common unless perhaps elevation maps are bundled in with data, or the format contains both raw and calibrated data. But I don't want to immediately make the assumption that all datasets will have identical datatypes across all bands. I need to make a decision about if I need to support creation of multi-datatype files and was hoping to get feedback on if users out there felt this was a safe assumption or a bad one.
Thanks in advance !
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