DescribeCoverage Not Throwing Exception on Illegal Coverage

[warmerdam]

Currently no exception is thrown if a coverage is requested that does not
exist, but I *think* there should be an exception. 

I would add that the exception should be thrown in the case of a coverage
name that is a layername which isn't enabled for WCS support as well as the
case of a coverage name with no analog in the mapfile.

[fwarmerdam]

On a vaguely related point, I discovered that a DescribeCoverage call for
a file that can't be opened (ie. GDALOpen() returns NULL) results in a 
call to msSetError() but this error message is not returned to the user as
an exception. 

[fwarmerdam]

Selecting a FORMAT that is not in the wcs_formats list results in the mime
header being returned, but no data being returned.  No exception is generated.
In this case the OUTPUTFORMAT declaration does exist.  An exception should be
produced. 

[tomkralidis]

Committed:

• msWCSDescribeCoverage: throw Exception if Coverage doesn't exist
• msWCSException: updated as per WCS 1.0 Appendix A.6

Currently, an Exception is thrown if a format is requested which is not supported. I couldn't reproduce Frank's format issue as per above.

Steve: can you verify? I haven't closed this one due to this issue.

[sdlime]

Replying to tomkralidis:

Tom, sorry it's not clear what you want me to verify?