Renamed thread per Ben's suggestion.
If a 2D client talks to a 4D server, it has to be able to detect that
the WCS is beyond its capabilities but otherwise I'm not sure that much
additional complexity is imposed on clients. A process for describing
the dimensionality of the server is definitely important with an
N-dimensional WCS, but I think this is already largely covered by the
CRS description in the current WCS specification. I see it as another
flexible point in the specification. Just as the WCS does not mandate
any particular encoding format or specific CRS/data projection, it would
not mandate the dimensionality of the data. As in cases where an
unknown CRS is in use by a WCS server, a client makes a decision about
whether it is capable of handling that WCS implementation.
The reason I see N-dimensionality as preferable to a restricted
dimensionality is that the restriction:
-forces non-2D WCS implementors to fulfill a more complicated extension,
even when simple core functionality is all that is needed
-increases the number of necessary extensions, at least with how the
current extensions are described and laid out. Minimizing the number of
extensions seems beneficial to interoperability overall
-seems to cut the WCS functionality into groupings at a different angle
than the general coverage concept (i.e. less generalized coverage
capability)
Are there cases I am forgetting that might cause problems for 2D
implementors?
Aaron
Wenli Yang wrote:
George,
Core requires a "DomainSubset" element. While the DomainObject can be n-D. Core
requires the DomainSubset with BoundingBox parameter but does not require TemporalSubset. For the
BoundingBox, it requires 2D, which I believe refer to "two near horizontal Ds".
If an implementation implements 3D (or >2D), it should have the capability of 2D as
well, unless the 3- or n-D (n>2) does not include the "two near horizontal Ds).
I guess that the requirement in core on "two near horizontally Ds", which are
traditionally geographic/cartographic Ds (i.e., geographic or projected CRSs), may cause
problem for some of the metaocean data such as the vertical profile data I mentioned in
one of my previous email. A profile may have only one horizontal D and one or more other
Ds such as time and pressure.
Wenli
