[mapserver-dev] MS 5.4 - Python-MS - queryByRect strange behavior

Steve Lime Steve.Lime at dnr.state.mn.us
Mon Nov 9 13:55:48 EST 2009

A small test case will really help if you can create one that way we can try independently
of MS4W. As I read this it seems that you're doing a rect query on inline shapes. I don't 
recall if that code changed a bit in 5.4 or not. Perhaps Tamas can confirm.


>>> On 11/6/2009 at 12:00 PM, in message
<aa5471510911061000v380ab8fbld95a294e4b784496 at mail.gmail.com>, Christian Jauvin
<cjauvin at gmail.com> wrote:
> Hi everyone,
> I am currently developing a Python-MapScript based web-mapping
> framework (http://dracones.surveillance.mcgill.ca) that worked fairly
> well with earlier versions of MS (MS4W < 3 on Windows, and
> package-based MS ~ 5.2 on Linux). This week I started playing with
> Python 2.6 (looking, among other things, to port my framework from
> mod_python to WSGI), and so it lead me to the latest beta of MS4W,
> which I read has a version of Python-MS built for it. I am currently
> using the Beta 7 of MS4W 3. I originally posted this to the MS4W-users
> list only, suspecting that my problem was specific to it, but I was
> then advised to post here as well, as it could point to a deeper MS
> issue.
> I have noticed a strange behavior with the queryByRect function,
> different than what was before: when I programmatically add features
> to a point layer and then try to retrieve a subset of them with
> queryByRect, getNumResults gives the correct number of retrieved
> features, but then the set of shapes returned by
> layer.getFeature(layer.getResult(i).shapeindex) is not right. The best
> way to explain the problem is this example: when I query for three
> very distinct features, what I get is this:
>  [<mapscript.shapeObj; proxy of <Swig Object of type 'shapeObj *' at
> 0x01EC71E0> >,
>   <mapscript.shapeObj; proxy of <Swig Object of type 'shapeObj *' at
> 0x01EC71C0> >,
>   <mapscript.shapeObj; proxy of <Swig Object of type 'shapeObj *' at
> 0x01EC71E0> >]
> The first and third objects seem to be the same, according to their
> pointers. No matter what query I try to perform, there is always a
> similar problem occurring: some pointers seem to be pointing to shared
> features, whereas they shouldn't (at least from what I understand).
> I understand that this problem description may not be terribly helpful
> since it may be hard to reproduce, but given that it would take time
> to abstract away the suspicious code in my framework, I thought that I
> would go for the high-level first, in case I am missing something
> obvious. I am ready to try building a more thorough test case and file
> it, if needed however.
> Thanks in advance for any help,
> Christian
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