[Mapserver-users] mapscript - queryByPoint help, simple Q
Eric Bridger
eric at gomoos.org
Thu Aug 28 08:01:07 EDT 2003
You must put addFeature inside the loop (I would also put ms_newShapeObj
inside the loop. After the loop call $layer->draw().
Note, in perl mapscript queryByPoint() returns 0 on success and 1 on
failure. Probably the same in PHP mapscript. That was the problem in
the post you cited below.
One other thing to check is $uLayer->queryByPoint($my_point, MS_SINGLE,
-10) ?? What does -10 signify. I believe this is the query's TOLERANCE
and should be greater than 0, e.g. 10.
On Thu, 2003-08-28 at 14:51, poff wrote:
> Thank you for your help - I tried to translate to phpmapscript and came up
> with:
>
> $shp=ms_newShapeObj(MS_SHAPE_POINT);
>
> ... loop through points
>
> $oPoint=...
>
> $line=ms_newLineObj();
> $line->add($oPoint);
> $shp->add($line);
> $shp->index = $i;
> $i++;
> ...
>
> $uLayer->addFeature($shp);
>
> $my_point = ms_newpointObj();
> $my_point->setXY($_REQUEST["mapa_x"],$_REQUEST["mapa_y"]);
>
> $result=$uLayer->queryByPoint ($my_point,MS_SINGLE,-10);
>
> But alas still "No Results"
>
> Is there anything wrong with the above? I have the Dummy TEMPLATE in the
> map file.
>
> I just found:
>
> http://lists.gis.umn.edu/pipermail/mapserver-users/2003-April/003470.html
>
> Who seems to have (had) exactly the same problem as I.
>
> Any ideas?
>
> Thanks again!
>
> P
>
> ps. I put the shpObj and addfeature inside the loop with no change in
> results.
>
>
> On Thu, Aug 28, 2003 at 10:02:06AM +0000, Eric Bridger wrote:
> > For such a layer you need to add the points as features in order for
> > them to be queryable (as well as having the dummy TEMPLATE).
> >
> > So for each point you can't just do $point->draw($map, $layer, $img,
> > undef, $text) you also need to do:
> > $layer->addFeature($shp). Since addFeature requires a shape object you
> > need to create the shape:
> >
> > my $line = new mapscript::lineObj();
> > $line->add($point);
> > my $shp = new mapscript::shapeObj($mapscript::MS_SHAPE_POINT);
> > $shp->add($line);
> > $shp->setBounds();
> > $shp->{index} = $point_number;
> >
> > Sorry these examples are in perl. One neat thing, the $shp->{index}
> > value can be any number, so if you have a numeric database key you can
> > use that and queryByPoint() results will return the key. I you don't
> > have that you'll need to create a lookup array which maps each database
> > key value with the point number in the layer.
> >
> > You need to draw the layer before queryByPoint can be called.
> >
> > What I have been doing for dynamic point layers is to call both
> > point->draw() and layer->addFeature() but not layer->draw(). With the
> > point->draw() I can control the color, size, text, etc. of each point
> > using the layers class. The addFeature() makes the layer queryable w/o
> > a shapefile.
> >
> >
> > There is a perl example here:
> > http://mapserver.gis.umn.edu/cgi-bin/wiki.pl?PerlMapScriptExamples35ex14
> >
> > Eric
> >
> > On Thu, 2003-08-28 at 13:06, poff wrote:
> > > > Do you have a template defined for the layer?
> > >
> > > No, sounds like I should!
> > >
> > > I have never used templates before, but in the query layer, and the point
> > > class I added:
> > >
> > > TEMPLATE "dummy"
> > >
> > > And instead of No Records I get:
> > >
> > > Warning: MapServer Error in msOpenSHPFile(): No (NULL) filename provided
> > >
> > > So it seems like progress!
> > >
> > > $result=$uLayer->queryByPoint ($my_point,MS_SINGLE,-10);
> > >
> > > Generates this error, but I didn't think I'd need a SHP file or anything.
> > >
> > > Any ideas how to proceed?
> > >
> > > Thanks very much!
> > >
> > > P
> > >
> > > > Lowell
> > > >
> > > > The following message was sent by poff <poff at sixbit.org> on Thu, 28 Aug
> > > > 2003 09:54:37 +0200.
> > > >
> > > > > Hello again,
> > > > >
> > > > > I'm having problems getting any results with queryByPoint.
> > > > >
> > > > > Basically I draw my map as usual then I try the following on the drawn
> > > > > layer:
> > > > >
> > > > > $my_point = ms_newpointObj();
> > > > >
> > > > > $my_point->setXY($_REQUEST["mapa_x"],$_REQUEST["mapa_y"]);
> > > > >
> > > > > $result=$uLayer->queryByPoint ($my_point,MS_SINGLE,-20);
> > > > >
> > > > > I tried different buffers, zooming in etc. but I always get: "No matching
> > > > > Record(s) found"
> > > > >
> > > > > The layer is drawn OK, and is simple as far as the mapfile goes (nothing
> > > > > apart from):
> > > > >
> > > > > ...
> > > > > STATUS ON
> > > > > TYPE POINT
> > > > > LABELCACHE FALSE
> > > > >
> > > > > CLASS
> > > > > SYMBOL
> > > > > END
> > > > >
> > > > > END
> > > > > ...
> > > > >
> > > > > The points are drawn in from a database, so if I could convert the
> > > > > $_REQUEST clicks into lat/lon I could just query the database instead of
> > > > > mapserver.
> > > > >
> > > > > Has anyone got any light to shed on this? I'd be most grateful if someone
> > > > > could show me what I'm doing wrong, or suggest how to get the lat/long
> > > > > values. The archives didn't seem to have anyone in my situation - which
> > > > > suggested to me I'm missing something basic out.
> > > > >
> > > > > Thanks in advance,
> > > > >
> > > > > --
> > > > > poff at sixbit.org
> > > > > SDF Public Access UNIX System - http://sdf.lonestar.org
> > > > >
> > > > > Please do not carbon copy replies to me
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> > > >
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> > >
> > > --
> > > poff at sixbit.org
> > > SDF Public Access UNIX System - http://sdf.lonestar.org
> > >
> > > Please do not carbon copy replies to me
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> > >
> >
> >
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>
> --
> poff at sixbit.org
> SDF Public Access UNIX System - http://sdf.lonestar.org
>
> Please do not carbon copy replies to me
> _______________________________________________
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>
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