Hey Joe,

I think that #2 below (org.unitsofmeasurement) would be a good package for
this.

Thoughts?

Cheers,
Chris

On 12/4/12 4:00 PM, "Joe White" <[email protected]> wrote:

>I'm also with Chris on this.  If we can find a package to handle the
>dirty bits and wrap it with the correct interfaces to get us through,
>then move to a "better" implementation as we go, I think we should.  Does
>anyone have any suggestions for a library that is nicely licensed that
>has this functionality?
>
>Joe
>On Dec 4, 2012, at 5:14 PM, Adam Estrada <[email protected]> wrote:
>
>> I will agree with Mattmann about the license compatibility issues. As
>>for
>> GeoAPI, why has nothing been done with that project in so long? Don't
>>want
>> to hijack this thread but it seems like the projects could benefit each
>> other nicely. Why is that not happening? For the time-being I believe we
>> should set the stage for a "next generation" geospatial framework in
>>SIS.
>> 
>> 
>> On Tue, Dec 4, 2012 at 12:41 AM, Mattmann, Chris A (388J) <
>> [email protected]> wrote:
>> 
>>> Hi Martin,
>>> 
>>> If it's not too much trouble, 2, then 2b seem to be the best choices
>>>IMHO.
>>> We take something with a friendly academic, permissive
>>> license now, compatible with Apache SIS and ALv2, and then as we need,
>>>we
>>> provide our own implementation as we evolve. Seems
>>> small, and incremental enough for consensus :)
>>> 
>>> Cheers,
>>> Chris
>>> 
>>> On Dec 1, 2012, at 8:33 AM, Martin Desruisseaux wrote:
>>> 
>>>> Hello all
>>>> 
>>>> There is a technical problem for which the current situation is not
>>> satisfying, and for which I have trouble to find the best action...
>>>> 
>>>> We needs a "Unit of measurement" framework. Because this is important
>>>>to
>>> so many domains (even the JDK has a TimeUnit class), we made a
>>> standardisation attempts 12 years ago (JSR-108), which failed [1]. We
>>>made
>>> a second attempt (JSR-275), which failed again [2]. GeoAPI - and
>>> consequently current Apache SIS - currently have a dependency toward
>>>this
>>> failed JSR-275 attempt. This obviously brings two problems:
>>>> 
>>>> 1) JSR-275 namespace (javax.measure.unit) is not supposed to exist.
>>>> 2) JSR-275 bugs will never be fixed.
>>>> 
>>>> After JSR-275 rejection, the main JSR-275 authors moved their API as
>>> interfaces in the "org.unitsofmeasurement.unit" package under a
>>>BSD-like
>>> license [3]. Those interfaces are implemented by the Eclipse UOMo
>>>project
>>> among others [4], and his maintainer told me that they are gaining
>>> acceptance in the Eclipse community.
>>>> 
>>>> However the maintainer told me that a sensor-related JSR have good
>>> chances to start in 2013, could include units of measurement, and that
>>>they
>>> want to go fast. This would bring yet another package name in the mix
>>>(or
>>> maybe they would reuse the javax.measure.unit one - we don't know). So
>>>the
>>> alternatives at this time are:
>>>> 
>>>> 1) Keep JSR-275 for now, wait and see.
>>>> 2) Adopt org.unitsofmeasurement interfaces, then:
>>>> 2a) Adopt UOMo implementation
>>>> 2b) Provide our own implementation
>>>> 3) Define our own interfaces
>>>> 
>>>> On 1), we are already waiting for two years and I still have trouble
>>>>to
>>> figure out if yes or no a third JSR attempt will happen... On 2), the
>>> problem is that the decision does not involve only SIS, but also
>>>GeoAPI,
>>> and as a standardisation attempt we are better to be as sure as
>>>possible
>>> that we will not change again if, for example, Oracle starts a new
>>>JSR. On
>>> 2a), I have not tried this UOMo implementation. But I had some trouble
>>>with
>>> the JSR-275 implementation. Many statics methods in the Units class
>>>that I
>>> just committed today [5] are workarounds for JSR-275 bugs or
>>>limitations.
>>> Some methods like "valueOfEPSG" (scroll down until the bottom of the
>>>page)
>>> are very specific to the geospatial domain and unlikely to be supported
>>> natively by an external unit framework. The NetCDF unit names
>>> ("degrees_east", "degrees_north") are also quite specific, so maybe
>>>having
>>> our own implementation is not completely non-sense. On 2b) actually we
>>> already have an implementation from old JSR-108 days, so it could be
>>>easily
>>> refactored to "org.unitsofmeasurement" interfaces. On 3), it would
>>>need to
>>> be done in GeoAPI I don't think it would have a lot of support...
>>>> 
>>>> The GeoAPI working group is not active at this time, so I suspect that
>>> we may have more discussion on this SIS list, then brings a proposal
>>>to the
>>> GeoAPI list. This proposal (about interfaces only - the implementation
>>> decision stay on the SIS side only) would need to be written as a
>>>change
>>> request and posted before December 27 if we want it to be considered
>>>at the
>>> next OGC meeting.
>>>> 
>>>> Any though, opinion, proposal would be highly appreciated...
>>>> 
>>>>   Regards,
>>>> 
>>>>       Martin
>>>> 
>>>> 
>>>> [1] http://jcp.org/en/jsr/detail?id=108
>>>> [2] http://jcp.org/en/jsr/detail?id=275
>>>> [3] http://www.unitsofmeasurement.org/
>>>> [4] http://www.eclipse.org/uomo/
>>>> [5]
>>> 
>>>https://builds.apache.org/job/sis-jdk7/site/apidocs/org/apache/sis/measu
>>>re/Units.html
>>>> 
>>> 
>>> 
>

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