Geometry Boost List: Re: [geometry] Rtree changes

Subject: Re: [geometry] Rtree changes
From: Adam Wulkiewicz (adam.wulkiewicz_at_[hidden])
Date: 2013-02-18 12:16:29

Mateusz Loskot wrote:
> On 18 February 2013 16:35, Mats Taraldsvik <mats.taraldsvik_at_[hidden]> wrote:
>>
>> - Will it be possible to use rtree queries on external (indexable) objects?
>> For example, if I have a rtree-indexed boundary, and a set of not-indexed
>> objects, and want to check if the objects intersect with my boundary.
>> Essentially a kind of prepared query like the PreparedGeometry in GEOS.
>
> Assuming geos::geom:: types are adapted as boost::geometry models,
> I'd expect it should be possible. But, I'm also curious Adam's opinion here.

Spatial predicates which may be passed to the query may take arbitrary 
Geometry type. To compile properly there must be an algorithm, e.g. 
geometry::intersects() which is able to calculate the result for 
Indexable and Geometry. So for example it's possible to query for Values 
intersecting MultiPolygon. If you store border segments in the rtree 
e.g. as std::pair<SegmentBox, SegmentId> and define MultiPolygon 
containing other geometries it should return intersected Values. Does it 
meet your requirements?

Additionally, if new Geometries were added to the Boost.Geometry and 
algorithms implemented for them the rtree should automatically work for 
them.

For example, it should be possible to add some CompoundGeometry or 
IndexedGeometry concept which stores some number of Geometries and a 
SpatialIndex inside (or just the SpatialIndex) and implement 
geometry::intersects(Box, CompoundGeometry) which uses this stored 
internally SpatialIndex to calculate the result. And this should 
automatically work in the rtree.

In the docs there are some basic examples of geometries for which query 
may be performed:

https://svn.boost.org/svn/boost/sandbox-branches/geometry/index/doc/html/geometry_index/r_tree/queries.html

Regards,
Adam