Re: [Boost-users] [units][geometry] subtract_typeof_helper<> help!

Subject: Re: [Boost-users] [units][geometry] subtract_typeof_helper<> help!
From: Barend Gehrels (barend_at_[hidden])
Date: 2011-01-01 17:34:08

Hi,

>  Second, I would like to pick the attention of Boost.Geometry again in 
> order to suggest them use boost.units as a way to make the 
> Boost.Geometry library very general.
> (...)
> I think none of the two options makes general sense. The only point at 
> which units make sense is at the "metric" of the space. Since in 
> Boost.geometry library coordinate system an metric are tied together, 
> we need a special type of coordinates system. For example one 
> suggestion could be to extend the coordinate systems of Boost.Geometry 
> to include the units and dimension of space. For example one way to 
> specify points in space could be by means of a type like this
>
>  model::point<double, 3, cs::unit::cartesian<si::length> >
>
> and then specialize all the template functions that use cartesian as 
> coordinate system, for example distance. This makes sense because the 
> only point at which units are useful is when we take distances, 
> modulus or projections between vectors in that "space" with 
> unit/dimension.

I will look at this usage soon.

Thanks, Barend