GeoTIFF Tiff Tag version of spec?

[cholmes]

One potentially instantiation of the metadata spec is to put fields directly in to GeoTIFF files as tiff tags.

GDAL can read and write these. From the GDAL docs: 'Other non standard metadata items can be stored in a TIFF file created with the profile GDALGeoTIFF (the default, see below in the Creation issues section). Those metadata items are grouped together into a XML string stored in the non standard TIFFTAG_GDAL_METADATA ASCII tag (code 42112).' on http://www.gdal.org/frmt_gtiff.html

Planet data accessed through the PLScenes driver would populate metadata fields in the geotiff with the image properties. Having software that produces imagery in this way would ensure that a sidecar metadata file would never just be 'lost'.

The profile could rely on more standard geotiff constructs for footprint, projection and acquisition, and then add in the additional information.