[OpenLayers-Users] Fwd: Turning on/off layers depending on zoom level

Wed Apr 25 21:17:13 EDT 2007

sending again without the build OL patch -- msg too big for list :-)
erik

---------- Forwarded message ----------
From: Erik Uzureau <erik.uzureau at metacarta.com>
Date: Apr 25, 2007 8:15 PM
Subject: Re: [OpenLayers-Users] Turning on/off layers depending on zoom
level
To: kaka <drspencer at hotmail.com>
Cc: users at openlayers.org

Hello,

I have found some more time to look at this, and with your helpful
description I think I am able to see the problem (and maybe solve it).

The problem is that if the layer is out of range to start with, we never
hide it. That's not good.

I am including a patch that seems to fix this problem in your code.

Can you tell me if this fixes it for you?

If you don't know how to apply patches, I've also included a freshly build
OL from trunk with this patch put in.

Please let me know if this fixes your problem. I would like to open a ticket
for this bug. It won't make it into the 2.4 release but in 2.5 for sure.

Thanks for your bug report and your patience with explaining it :-)
Erik

On 4/22/07, kaka <drspencer at hotmail.com> wrote:
>
>
> The problems I have with the maxResolution are:
>
> a) the markers are dislocated. Have a look at the link I posted and try
> zooming out - the markers end up in the wrong positions.
>
> b) the markers are visible when thy should not appear. I would like them
> to
> appear when I zoom in the map, and not on first load. However, I keep
> having
> trouble with this. If they are set to show in the 0.03 resolution, the
> example works just fine. If I set them to 0.02, or any other resolution
> that
> should make them not to render on first load, the example does no longer
> work as expected. The markers are drawn anyway and in the wrong location
> as
> mentioned in a).
>
> Any help appreciated.
>
> Magnus
>
>
>
> Erik Uzureau-3 wrote:
> >
> > Kaka,
> >
> > It is hard for people to help you because we need a more detailed
> > description of the problem.
> > I personally do not understand what is going wrong here.
> > Erik
> >
> > On 4/17/07, kaka <drspencer at hotmail.com> wrote:
> >>
> >>
> >> Any help on this issue would be greatly appreciated. Could it be that
> >> this
> >> is
> >> a bug? The example is over at
> >> http://www.villageografica.com/test44/Africa-test.html and my problem
> is
> >> that the maxResolution doesn´t work with the zoom ranges I want and,
> >> also,
> >> that the markers are not in the correct position.
> >>
> >> Magnus
> >>
> >>
> >>
> >>
> >> kaka wrote:
> >> >
> >> > This is an example of the problem I have:
> >> >
> >> > http://www.villageografica.com/test44/Africa-test.html
> >> >
> >> > If I change the maxResolution to 0.2 the map works fine, but its
> >> current
> >> > 0.3 won´t work. I hope this illustrates my problem.
> >> >
> >> > Magnus
> >> >
> >> >
> >> >
> >> > Erik Uzureau-3 wrote:
> >> >>
> >> >> Dear Kaka,
> >> >>
> >> >> Do you have a live example that you could post a link to?
> >> >> Offhand, I can't see what the problem is... but I might be
> >> >> able to help you out if I could see it in action
> >> >>
> >> >> Erik,
> >> >> Best
> >> >>
> >> >> On 4/10/07, kaka <drspencer at hotmail.com> wrote:
> >> >>>
> >> >>> Thank you very much, Erik, this has been a great help. However, I
> >> have
> >> >>> run
> >> >>> into a problem. If the markers are set to not show on first load,
> but
> >> to
> >> >>> appear when zooming in, the show/hide functionality stops working
> and
> >> >>> the
> >> >>> markers are dislocated when zooming out. My code looks like this:
> >> >>>
> >> >>> var MarkersLayer2 = new OpenLayers.Layer.Text( "Region info",
> >> {location:
> >> >>> "markers.txt", maxResolution: 0.03});
> >> >>>
> >> >>> Changing the "0.3" to "0.2" causes the problems mentioned above. Is
>
> >> this
> >> >>> related to my code or a possible bug?
> >> >>>
> >> >>> Magnus
> >> >>>
> >> >>>
> >> >>>
> >> >>>
> >> >>> kaka wrote:
> >> >>> >
> >> >>> > Hi
> >> >>> > I am trying to turn on/off a layer of markers depending on zoom
> >> level,
> >> >>> > using google maps as a background layer. Does anyone have
> >> suggestions
> >> >>> on
> >> >>> > how to achieve this or is there or maybe an example? Thank you
> for
> >> any
> >> >>> > ideas.
> >> >>> >
> >> >>> > Regards,
> >> >>> >
> >> >>> > Magnus
> >> >>> >
> >> >>>
> >> >>> --
> >> >>> View this message in context:
> >> >>>
> >> http://www.nabble.com/Turning-on-off-layers-depending-on-zoom-level-tf3550126.html#a9927966
>
> >> >>> Sent from the OpenLayers Users mailing list archive at Nabble.com.
> >> >>>
> >> >>> _______________________________________________
> >> >>> Users mailing list
> >> >>> Users at openlayers.org
> >> >>> http://openlayers.org/mailman/listinfo/users
> >> >>>
> >> >> _______________________________________________
> >> >> Users mailing list
> >> >> Users at openlayers.org
> >> >> http://openlayers.org/mailman/listinfo/users
> >> >>
> >> >>
> >> >
> >> >
> >>
> >> --
> >> View this message in context:
> >> http://www.nabble.com/Turning-on-off-layers-depending-on-zoom-level-tf3550126.html#a10048769
>
> >> Sent from the OpenLayers Users mailing list archive at Nabble.com.
> >>
> >> _______________________________________________
> >> Users mailing list
> >> Users at openlayers.org
> >> http://openlayers.org/mailman/listinfo/users
> >>
> >
> > _______________________________________________
> > Users mailing list
> > Users at openlayers.org
> > http://openlayers.org/mailman/listinfo/users
> >
> >
>
> --
> View this message in context: http://www.nabble.com/Turning-on-off-layers-depending-on-zoom-level-tf3550126.html#a10129213
>
> Sent from the OpenLayers Users mailing list archive at Nabble.com.
>
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