[Geotools-gt2-users] Using an CSAuthorityFactory to look up by Unit?

[Jody G. <jga...@re...>]

Hi Matthias; the CSAuthorityFactory has changed a bit over time; I 
confirm that the functionality you are looking for is not available on 
trunk.
The intention of the getAuthorityCodes method was not to look up codes 
for a Unit; but to look up codes for a specific kind of object being 
managed. ... ie IdentifiedObjects all of a code - this method is 
supposed to return a list of all the codes for that kind of object.

Identified objects in the system right now:
- CoordinteOperation
- CoordinateSystem
- CoordinateAxis
- Datum
- Ellipsoid
- ReferenceSystem (including CoordinateReferenceSystem)
- etc...

Now your request to look up units is also valid ... units have switch 
over to JSR-275 so let us explore what they have going on. I am used to 
looking up units as static constants (NonSI.FOOT and SI.METER for 
example) but I know there is some run time facilities as well...

The best I can find is the SystemOfUnits.getUnits() Set<Unit<?>> method 
... which both SI and NonSI extend.

I am not sure however about discovering all the SystemOfUnits 
implementations on the classpath...however they must have something 
because hey have parsing methods around ...

Jody

Matthias Basler wrote:
> Hi all,
>
> today I decided I should upgrade GISWidgets to use the latest GeoTools version, namely 2.5 RC1 (it used 2.3 before). Most changes seem cosmetical and can be solved easily, but I run into a problem where I am missing functionality in 2.5. that existed (intended or not) in 2.3.x:
>
> How to query all available units (length, angle) from an authority factory. In particular I want all units supported by EPSG.
> I have never been able to retrieve linear and angular units separately, but with GeoTools 2.3 the following worked:
>     CSAuthorityFactory csFactory = ...
>     Set<String> codes = csFactory.getAuthorityCodes(Unit.class);
> Now this method requires the interface "IdentifiedObject", which is not supported by the Unit class.
>
> I had a look at the user guide, but all I found was related to "IdentifiedObject"s.
>