[geos-devel] re:GEOS

[Artem Pavlenko]

Dear List,

Firstly, thanks for all your efforts to provide an opensource 
implementation of spatial algorithms.
I am the developer of  http://mapnik.berlios.de  project and am at the 
moment thinking about having a go at implementing OGCs Filter/SLD (or 
subset of it) in C++ . So I'm very into GEOS becoming more robust, 
standard and easier to integrate ... (I guess that is the point of the 
project).

I hope you don't mind me butting in; I'm just a potential user and I 
don't claim any great authority in C++. My aim is simply to start using 
GEOS ASAP. On this basis, I have a couple of comments/ suggestions.

I've noticed that there are some changes in CVS and I'm glad to see the 
following:

LineIntersector::LineIntersector()
{
    precisionModel=NULL;
    Coordinate *c=new Coordinate();
    intPt[0].setCoordinate(*c);
    delete c;
    c=new Coordinate();
    intPt[1].setCoordinate(*c);
    delete c;
    // alias the intersection points for ease of reference
    pa.setCoordinate(intPt[0]);
    pb.setCoordinate(intPt[1]);
    result=0;
}

becoming :
 
LineIntersector::LineIntersector(): pa(intPt[0]), pb(intPt[1])
{
    precisionModel=NULL;
    // alias the intersection points for ease of reference
    //pa=intPt[0];
    //pb=intPt[1];
    result=0;
}
   
But to me, this is still a wrong use of C++. From what I can see, this 
is one example of many, maybe as a result of translating Java into C++? 
I would be honoured to suggest some changes/ideas, if anybody agrees 
with me:)

I also have some questions about future directions. As I see it, there 
can be lots to gain from introducing templates, because:
1. you're using them already as part of STL
2. they might lead to better performance
3. you'll able to abstract things like memory allocation and precision 
models, allowing clients to configure the library the way they like and 
concentrate on actual algorithms
4. templates are part C++ ISO!

And also there is boost.org and you will be dealing with smart pointers 
at some point, so why not now?
I'm also working with couple datastructures that might be beneficial to 
GEOS.

Anyway, all this is meant to be constructive, and I'm happy to discuss 
anything or for anybody to put me right if I'm missing something!

Cheers!
Artem