[boost] [GGL] Initial thoughts; how to register point types

Subject: [boost] [GGL] Initial thoughts; how to register point types
From: Phil Endecott (spam_from_boost_dev_at_[hidden])
Date: 2009-11-14 10:19:51

Dear All,

Following is some initial feedback on GGL, after spending an hour or so 
with the docs.  I hope to be able to complete a proper review over the 
next couple of days.

The documentation seems very much focused on "how it works", which is 
of course useful for reviewing the design, but more "what it does" and 
"how to use it" content would help me to actually try it with some 
examples.  For example, I have a Point<T> class and I would like to 
"teach" the library about it.  From the "Design rationale" page I can 
see that a number of traits have to be defined, but I don't see a 
concise reference to what I need to do.  Looking at the example 
"c01_custom_point_example.cpp" I see that there are some macros e.g. 
GEOMETRY_REGISTER_POINT_2D (not a Boost-style macro name by the way) 
but I don't see any documentation for what these do.  I guess that it 
defines some traits specialisations, right?

Does anyone know how to get Doxygen to create next/prev buttons for 
navigating between the pages in the e.g. "related pages" section?

Is it possible to note which versions of the Boost library dependencies 
are needed?

I'm not convinced that overloading e.g. distance() so that it works 
with all combinations of geometries is a good idea.  If I wanted to 
know the distance from a point to a polygon I'd be happy to write 
distance_pt_to_poly(a,b).  Having the overload makes it possible for me 
to accidentally pass the wrong things and get no error.  And there is 
the question of what is meant by distance "to" a polygon - is it to the 
nearest point, or the centroid, etc?

I believe that heterogeneous co-ordinate types (e.g. latitude and 
longitude of one type and altitude of another) are not supported, right?

Regards,

Phil.