datum requested in GeographicCoverageType
Received a verbal request from Christine Laney for an element (or attribute) defining the datum to go with coverage/boundingCoordinates and altitudes (one each), to assist in creating accurate maps of datasets' locations. EML2 recommendations for boundingBox coordinates do not mention datum, and for boundingAltitudes, authors are told to include the datum with the altitudeUnit. datum is also missing from gPoint. This bug is related to bug #1019 (altitude units)
Updated by Margaret O'Brien over 14 years ago
I followed up on the issue of datums with a couple of geographers. The conclusion is that the current geographicCoverage/boundingCoordinates tree is adequate for its intended use. The request for a datum to be associated with locations of datasets is actually part of a larger issue that cannot be addressed in this part of EML - namely the integration of highly detailed spatial descriptions and the data that was collected there. Values of lat and lon that have been put into west|east|north|south elements may have been taken from the context of a projection system, but the description of that system does not belong under geographicCoverage.
The documentation for geographicCoverage should be updated before this bug is closed.
1. to state its intended use - that it is meant for general, not accurate mapping, and that information about mapping projections is covered by EML in the spatialReference schema.
2. the datum for lats and lons are implied -- ie, the equator and the prime meridian
See bug #1019 for a comment on vertical datum.