# Geometry :

Subject: AW: [ggl] Re: rtree ?
Date: 2011-12-02 12:22:37

Bernhard Schmitz wrote:
>
> attached is a very simple test that demonstrates the problem. I know that making a box out of a point does not make any sense, but I have the problem with other objects as well.
>
> Regards,
> Bernhard
>
>
>> -----Urspr?ngliche Nachricht-----
>> Gesendet: Freitag, 2. Dezember 2011 12:55
>> An: Generic Geometry Library Discussion
>> Cc: Bernhard Schmitz
>> Betreff: Re: [ggl] Re: rtree ?
>>
>> Bernhard wrote:
>>>
>>>>
>>>> Ok, I've improved it and added nearest neighbor query description. I
>>>> should have done it earlier. Feel free to report errors, ambiguities
>>>> etc. I hope that using of the rtree will be simpler task now.
>>>>
>>>
>>> thanks for the documentation, it is helping me a lot.
>>>
>>> However, right now I have the problem, that I can only insert as many
>>> objects as the first parameter of the splitting algorithm parameter. So,
>>> with your usual example of index::linear<32, 8>, I can insert exactly 32
>>> objects. If I add more, size() will return the total number of objects I
>>> inserted, but only the first 32 will be found by a query.
>>> Is this a huge bug, or intentional? Or am I doing something wrong?
>>>
>>> I noticed that upon insertion, the translator is only called by the
>>> INDEX_ASSERT, and nowhere else.
>>
>> The tree should return all of the objects. Could you please send the code?
>>
>> Regards,

Ok, the problem is with passing reference to temporary object. If
translator is returning Indexable instead of Indexable const&, temporary
object was created.

I fixed it by explicitly defining Translator's result type instead of
just indexable's type. Now your translator should look like this:

struct myTranslator
{
typedef BGCartesianBox result_type;

result_type operator()(BGCartesianSegment const& seg) const
{
result_type envelope;
boost::geometry::envelope(seg, envelope);
return envelope;
}

/*...*/
};

If someone has better idea how to distinguish between resulting types
I'm open to suggestions.

Btw, maby it would be better to use std::pair<Box, Segment> and default
Translator. Or even store segments in some vector and use std::pair<Box,
size_t>. The r-tree wouldn't be forced to calculate envelopes each time
it want something from the Value.

Regards,