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From: Barend Gehrels (barend_at_[hidden])
Date: 2008-01-15 03:59:52


Thanks for your answers. This reply answers them.

> How about is your experience now? How long to publish the library? I
want to have a sight on the library as soon as possible.
There are more answers possible. I'm busy with the samples and
documentation. I can do a preview post next week or so.

The library, in OGC sense, is not complete. However, we already use it
since 1995 like this and do not miss the things which are not there. But
if the library is a candidate for Boost we might consider add some or
even all missing features. However, that will take some time and will
influence the timeframe of course.
For example: the algorithm "distance", prescribed by OGC, is implemented
for point-point and for point-line, of course, but not yet for
point-polygon, multipoint-polygon, etc. There are 6x6 combinations for
the 6 OGC geometries
(point,line,polygon,multi-point,multi-line,multi-polygon). So 6x6 cases
for all algorithms on two geometries: distance, disjoint, touches,
crosses, within, contains, overlaps, intersection, union and difference.
This delivers 6x6x10=360 methods, however, some have some overlap or are
easy (contains(a,b) = within(b,a) )


> a few weeks ago, the authors of the "geometric template library" asked the same question
I had seen the GTL but not this posting. GTL is another library than this one. There is not much overlap. In Boost documentation a section "other libraries" is often there and I will include the differences with GTL there.

> Basic Image AlgorithmS C++ Library (BIAS)

This is interesting, but this is also another library. It is huge and I
would need more time to compare, but I think there is not much overlap
too here. Is BIAS a boost candidate?

There are more libraries: TGL (another template library, which has some
more overlap, but still has a different approach), CGAL I already
mentioned, GDAL, GEOS, GFC and some inside larger libraries as Mapnik,
and some more specific as the polygon clipping library. I will mention
them in the "other libraries" section.

> I will greatly appreciate this type of library in Boost.
That is nice to hear and I agree, it should be there.

> I'm particularly interested in clipping generic 2D polygons
Clipping 2D polygons against rectangles is in the library, using the
Weiler Atherton algorithm. This could be extended to other polygons, the
algorithm supports that.

> Generic polygon triangulation would be a plus
Is not included at this moment.

> Do you have any timeframe for the publication of your library?
As above, I try to do a preview next week, and depending on the interest
and process I think May 08 should be feasable.

Barend Gehrels

Beman Dawes wrote:
> Barend Gehrels wrote:
>> Hi,
>> Is there any interest in a template geometry library?
> Yes, at least from me:-)
> --Beman
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