I would like to export a metadata file using gpt that shows the metadata information of the file (Abstracted_Metadata) and the processing chain it has undergone (Processing_Graph). My outputs are in GeoTIFF-BigTIFF format, so ideally I would like to export a xml file with the same filename, populated with the Abstracted_Metadata and Processing_Graph attributes. Is this possible?
Writing solely the metadata is not possible.
But you can export to another format, like NetCDF. This would include the metadata. Or you can write to BEAM-DIMAP. In this case you get a separate xml file. Actually the metadta is also included in th GeoTIFF file. But as there is no standardised way of storing metadata in GeoTiff, no other software can recognise what SNAP is writing. If you have the reading ofthe GeoTiff in your hands you can have a look at the TiffTag 65000. At this tag we store metadata about the product in xml format.