joanma747
commented
2 years ago In the current use case of "indices" it is ok to limit the Tag to unsigned long only. We can not be sure that other use cases require "SLONG" numbers It is now possible to store a LONG or a SLONG in a DOUBLE (trick). At the moment of writing the pull request, the case of using indices of the TMS was "necessary" but after more discussion this could com at the latter stage in a eventual "COG 1.1". In any case this is "the kicken and egg problem": if there is no Tag you cannot create long keys until someone demonstrate the need first.
WE will will "park" this pull request until we better demonstrate the need in real cases.
In the COG standard draft created in the Testbed 17, we need new GeoTIFF tags. One of them needs to contain an array of long values. Unfortunately this was not foreseen in the current version of the GeoTIF 1.0 or 1.1. We request to extend the v1.2 with the support for this by adding a new TIFF tag called "GeoLongParamsTag" that will use the ID = 34738 that is the immediately available number after GeoAsciiParamsTag (ID = 34737). Please, consider it by adding support to bigTIFF, it is also necessary to have a an array of LONG8 (int64) values. This need has not emerged yet but it could.