Geometry Boost List: Re: [geometry] Support for geographic coordinate system

Subject: Re: [geometry] Support for geographic coordinate system
From: Barend Gehrels (barend_at_[hidden])
Date: 2014-11-17 16:28:24

Hi,

Adam Wulkiewicz wrote On 14-11-2014 12:33:
> Hi,
>
> Menelaos Karavelas wrote:
>> On 14/11/2014 01:42 πμ, Adam Wulkiewicz wrote:
>>> Barend Gehrels wrote:
>>>> Adam Wulkiewicz wrote On 12-11-2014 1:48:
>>>>> bg::reference::sphere<>
>>>>> bg::reference::spheroid<>
>>>>>
>>>>> Or something like that, e.g. shorter.
>>>>> And then the tags could be:
>>>>>
>>>>> reference_spheroid_tag
>>>>> reference_sphere_tag : reference_spheroid_tag
>>>>>
>>>>> And in the future if we e.g. had model::sphere and Sphere concept, 
>>>>> sphere_tag could be derived from reference_sphere_tag and used as 
>>>>> a ReferenceSphere too.
>>>>
>>>> This looks all OK to me. Explicitly adding reference makes it quite 
>>>> clear - we reserve a model::sphere for later then too.
>>>> So this is then the ReferenceSphere Concept.
>>>>
>>
>> I have to admit I do not particularly like the name reference for the 
>> reference system, as it very much reminds me of references in C++. I 
>> would prefer something like
>> bg::reference_system::sphere<>
>> bg::reference_system::spheroid<> (I really do prefer this compared to 
>> ellipsoid)
>> or
>>
>> bg::geography_model::sphere<>
>> bg::geography_model::spheroid<>
>>
>> Similarly for the tags. Among the two options I mention above I 
>> prefer the second, but can happily live with the first.
>>
>
> Yes, indeed the word "reference" may be confusing, though I think that 
> we should just choose a name describing well the content. But ok, 
> maybe we could pick something different. Note that the 
> reference_system also has the word "reference" in it.
>
> I'd rather avoid the word geography. I know that the main purpose is 
> to use it on in a GIS field but it should be general-purpose name. 
> What do you think about:
>
> bg::reference_model::spheroid<>
> bg::ref_model::spheroid<>
> bg::rmodel::spheroid<>
>
> They also have "reference" in a name and the last "r" might be 
> confused with "reverse".
>
>
> Since we already have bg::cs namespace, somehow related to the 
> reference system. We could reuse this scheme:
>
> boost::geometry::rs::spheroid<>

The common abbreviation is srs (spatial reference system), so as we get 
to that direction, I would certainly use that one. That would actually 
look quite good.

>
> but should spheroid and sphere be included in reference systems 
> (namespace)? They're rather models describing the ref systems. Though 
> it's possible that we'd need a place for more code related to 
> reference systems, EPSGs, SRIDs, etc. so this code could be put there. 
> But then I'd put the models in:
>
> boost::geometry::rs::model::sphere<>
> boost::geometry::rs::model::spheroid<>
>
> Or just reuse the namespace cs for this:
>
> boost::geometry::cs::model::sphere<>
> boost::geometry::cs::model::spheroid<>
>
> which would be probably the most general choice. The question is: 
> could additional things be put in the bg::cs namespace?

I think I would prefer the srs namespace.

Regards, Barend