Hi
The problem was not in mapserver but came from our script:
when the dpi is changed, the tolerance is globaly adjusted so all the
related features dont get over/undersized.
But when a value of -1 is used in queryByPoint, the global tolerance
recalculated result in -3.25~ when passing from 96 to 150 dpi
and mapserver do not know what to do with such value, it only understand -1
or >=0.
The problem was solved by specifying a special case when -1 was used in our
script for queryByPoint, so the tolerance stay at -1 at 96 and 150 dpi
Could you possible modify a bit the mapscript documentation of queryByPoint
?
It say "Passing buffer <=0 defaults to tolerances set in the map file ..."
but thats not exactly the case.
It would be "Passing buffer -1 defaults to tolerances set in the map
file..."
Thank you
Best regards
Oliver
----- Original Message -----
From: "Steve Lime" <[EMAIL PROTECTED]>
To: "Oliver Christen" <[EMAIL PROTECTED]>;
<mapserver-users@lists.osgeo.org>
Sent: Wednesday, July 09, 2008 6:39 PM
Subject: Re: [mapserver-users] mapscript queryByPoint - tolerancedepends
ofresolution ?
Tolerance computations are based on cellsize. Resolution affects only scale
computations, so it
is not clear to me how one could affect the other. I just went through the
code to verify. Is there
any chance that layer scale limits are coming into play here and you're not
querying the layer you
think you are? Does the behavior persist in 5.x?
If you can create a concise test case I'll gladly take a look.
Steve
On 7/9/2008 at 7:41 AM, in message
<[EMAIL PROTECTED]>,
"Oliver Christen" <[EMAIL PROTECTED]> wrote:
Hi
I have a problem when doing a queryByPoint with phpmapscript 4.10.1
By default, the resolution of my map is 96 dpi.
I do a queryByPoint on a layer containing polygonal areas. The point is
right in the middle of one area.
I use a default tolerance (-1) corresponding, if I read correctly the
documentation, to 3 pixels.
The result obtained is the area containing the coordinates I used, it's
absolutly normal and I get what I expect.
Now, if I dynamicaly change the resolution of the map to 150 dpi and then
do
exactly the same queryByPoint as before,
I get nothing!
Mapserver consider there was nothing at the coordinate I provided.
Then, if I redo the query, at 150 dpi, BUT with a tolerance set to 10
(instead of -1), I get a correct and expected result.
So, somehow, Mapserver seems to make some very weird calculation with the
tolerance and resolution which make it to believe there is nothing when
then
is something.
have you ever heard of such behaviour?
is that a bug?
any help would be very welcome.
thanks in advance
Oliver
_______________________________________________
mapserver-users mailing list
mapserver-users@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/mapserver-users
_______________________________________________
mapserver-users mailing list
mapserver-users@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/mapserver-users
