[geotk] Some questions about Geotoolkit CRS objects

[Jonathan Blower]

Hi all (esp. Martin I guess!),

I have a few questions about CoordinateReferenceSystem objects in
Geotoolkit, particularly those that are returned by the CRS.decode()
method:

1) Are the hashCode() and equals() methods always defined properly on
these objects?  In other words, can I safely use them as keys in a
HashMap?

2) If I have a CRS object that I got from CRS.decode(), then I find a
MathTransform to WGS84 using CRS.findMathTransform(crs,
DefaultGeographicCRS.WGS84, true);  (i.e. being lenient about datum
changes), can I always expect this to succeed?  In other words, how
likely is it that I'll get a FactoryException from findMathTransform?

3) How reliable is CRS.lookupEpsgCode()?  Can I "usually" expect this to
work correctly as the inverse of CRS.decode()?

Thanks in advance,
Jon

--
Dr Jon Blower
Technical Director, Reading e-Science Centre
Environmental Systems Science Centre
University of Reading
Harry Pitt Building, 3 Earley Gate
Reading RG6 6AL. UK
Tel: +44 (0)118 378 5213
Fax: +44 (0)118 378 6413
j.d.blower at reading.ac.uk
http://www.nerc-essc.ac.uk/People/Staff/Blower_J.htm