[mapserver-users] turning on layers at a particular zoom level
Rahkonen Jukka
Jukka.Rahkonen at mmmtike.fi
Wed Sep 2 08:53:07 EDT 2009
Oh, I should have read your question first. I try again. Use a comma separated list of layers, like layers:'STATE','Railwayline'. I am not at all sure about the exact syntax to be used with OpenLayers.
-Jukka-
> -----Alkuperäinen viesti-----
> Lähettäjä: mapserver-users-bounces at lists.osgeo.org
> [mailto:mapserver-users-bounces at lists.osgeo.org] Puolesta
> Rahkonen Jukka
> Lähetetty: 2. syyskuuta 2009 15:48
> Vastaanottaja: sunny74; mapserver-users at lists.osgeo.org
> Aihe: Re: [mapserver-users] turning on layers at a particular
> zoom level
>
> Hi,
>
> Collect the layers to one GROUP, and send requests against
> the GROUP instead of the original scale dependent layers.
> Mapfile may have something like this inside:
>
> LAYER
> GROUP "group"
> NAME "scale1"
> MAXSCALEDENOM 100000
> .
> .
> .
> END
>
> LAYER
> GROUP "group"
> NAME "scale2"
> TYPE POLYGON
> MAXSCALEDENOM 1000000
> MINSCALEDENOM 100000
> .
> .
> .
> END
>
>
> sunny74 wrote:
> >
> >
> > Hi,
> >
> > Thanks for the reply.
> >
> > 1) Can u tell me how to sandwich all the layers and make
> one WMS call
> > to the server and request all of the layers in one image/call.
> > Presently I am calling the layers separately as below:
> >
> > function init() {
> >
> > //alert("in init");
> > map = new OpenLayers.Map('<%=map.ClientID%>');
> >
> > //
> > layer = new OpenLayers.Layer.WMS("OpenLayers WMS",
> >
> > "http://172.16.128.173:8085/cgi-bin/mapserv.exe?", { map:
> > 'Shape/newwr1.map', layers: 'STATE', 'format': 'png' });
> >
> > layer1 = new OpenLayers.Layer.WMS("Rail Main",
> >
> > "http://172.16.128.173:8085/cgi-bin/mapserv.exe?", { map:
> > 'Shape/newwr1.map', transparent: 'true', layers: 'Railwayline' });
> >
> > // layer2 = new OpenLayers.Layer.WMS("Rail WaterBody",
> > //
> > "http://172.16.128.173:8085/cgi-bin/mapserv.exe?", { map:
> > 'Shape/newwr1.map', transparent: 'true', layers: 'WaterBody' });
> >
> > // layer3 = new OpenLayers.Layer.WMS("Rail Rail_Buffer",
> > //
> > "http://172.16.128.173:8085/cgi-bin/mapserv.exe?", { map:
> > 'Shape/newwr1.map', transparent: 'true', layers: 'Rail_Buffer' });
> >
> > // layer4 = new OpenLayers.Layer.WMS("Roads",
> > //
> > "http://172.16.128.173:8085/cgi-bin/mapserv.exe?", { map:
> > 'Shape/newwr1.map', transparent: 'true', layers: 'Roads' });
> >
> > // layer5 = new OpenLayers.Layer.WMS("Diversions",
> > //
> > "http://172.16.128.173:8085/cgi-bin/mapserv.exe?", {
> > map: 'Shape/newwr1.map', transparent: 'true', layers:
> 'Diversions' });
> >
> > // layer6 = new OpenLayers.Layer.WMS("Rail Side_Line",
> > //
> > "http://172.16.128.173:8085/cgi-bin/mapserv.exe?", {
> > map: 'Shape/newwr1.map', transparent: 'true', layers:
> > 'Rail_Side_Line' });
> > // layer7 = new OpenLayers.Layer.WMS("LANDMARKS",
> > //
> > "http://172.16.128.173:8085/cgi-bin/mapserv.exe?", {
> > map: 'Shape/newwr1.map', transparent: 'true', layers:
> 'LANDMARKS' });
> > layer8 = new OpenLayers.Layer.WMS("RailwayStations",
> >
> > "http://172.16.128.173:8085/cgi-bin/mapserv.exe?", { map:
> > 'Shape/newwr1.map', transparent: 'true', layers:
> 'RailwayStations' });
> > // layer9 = new OpenLayers.Layer.WMS("Bridges_Minor",
> > //
> > "http://172.16.128.173:8085/cgi-bin/mapserv.exe?", {
> > map: 'Shape/newwr1.map', transparent: 'true', layers:
> > 'Bridges_Minor' });
> > // layer10 = new OpenLayers.Layer.WMS("Bridge_Major",
> > //
> > "http://172.16.128.173:8085/cgi-bin/mapserv.exe?", {
> > map: 'Shape/newwr1.map', transparent: 'true', layers:
> > 'Bridge_Major' });
> > // layer11 = new OpenLayers.Layer.WMS("LC_Gate",
> > //
> > "http://172.16.128.173:8085/cgi-bin/mapserv.exe?", {
> > map: 'Shape/newwr1.map', transparent: 'true', layers: 'LC_Gate' });
> >
> > //
> >
> > highlight = new
> OpenLayers.Layer.Vector("highlight", { style:
> > vector_style });
> > choice_features = new
> > OpenLayers.Layer.Vector("choice_features", {
> > style: v_style });
> > distline = new OpenLayers.Layer.Vector("distline", { style:
> > vector_style });
> > //GML = new OpenLayers.Layers.GML("GML", { style:
> v_style });
> >
> > //
> > map.addLayers([layer, layer1, layer8, highlight,distline]);
> > // markers = new
> OpenLayers.Layer.Markers("markers");
> > // map.addLayer(markers);
> >
> > // map.OpenLayers.Control.PanZoom.destroy();
> > // map.OpenLayers.Control.MouseToolbar.destroy();
> > map.zoomToMaxExtent();
> > map.setCenter(new OpenLayers.LonLat(73.25, 20.35), 7);
> >
> > map.addControl(new OpenLayers.Control.PanZoomBar());
> > //map.addControl(new OpenLayers.Control.MouseToolbar());
> > map.addControl(new OpenLayers.Control.LayerSwitcher());
> > map.addControl(new OpenLayers.Control.MousePosition());
> >
> > map.addControl(new OpenLayers.Control.OverviewMap());
> > map.addControl(new OpenLayers.Control.Scale());
> >
> > }
> >
> > 2) Is there a way by which the layers will load at certain
> zoom level
> > bec'
> > in case of MAXSCALEDENOM /MINSCALEDENOM the layers are loading at
> > PageLoad while only visible at that zoom level.
> >
> > 3)If I use TileCache layer instead of Wms then will it load faster.
> >
> > Regards.
> >
> > Fawcett, David wrote:
> > >
> > > 1. You can use MINSCALEDENOM and MAXSCALEDENOM at either
> > the layer or
> > > class level (on a current version of MapServer). So, it
> looks like
> > > they are in an appropriate place. The real test is to use
> > MapServer
> > > to draw the layer for you. Does it turn on and off at the
> > scales that
> > > you want it to?
> > >
> > > 2. Yes, it can apply to both the layer or class
> > properties. I assume
> > > that you looked here:
> > > http://www.mapserver.org/mapfile/class.html#class
> > >
> > > 3. MapServer has nothing to do with when things load. This all
> > > happens on your client. It sounds like you modified your
> client to
> > > request each layer individually. If you just want to
> sandwich them
> > > all together, why not just make one WMS call to the server
> > and request
> > > all of the layers in one image/call. This question is
> really more
> > > appropriate for the OpenLayers list.
> > >
> > > 4. I would consult the TileCache or OpenLayers list for this one.
> > >
> > > David.
> > >
> > >
> > > -----Original Message-----
> > > From: mapserver-users-bounces at lists.osgeo.org
> > > [mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf
> > Of sunny74
> > > Sent: Saturday, August 29, 2009 2:01 AM
> > > To: mapserver-users at lists.osgeo.org
> > > Subject: RE: [mapserver-users] turning on layers at a
> > particular zoom
> > > level
> > >
> > >
> > >
> > > Hi David,
> > >
> > > Thanks for your reply.
> > > I wanted to have 3 layers displayed b/w scale of 1.2M and
> > 1.15M and so
> > > I have added set MAXSCALEDENOM /MINSCALEDENOM as follows:
> > >
> > > LAYER
> > > NAME 'WaterBody'
> > > TYPE POLYGON
> > > DATA 'C:\ms4w\Apache\cgi-bin\Shape\WaterBody.shp'
> > > METADATA
> > > 'wms_title' 'WaterBody'
> > > END
> > > STATUS OFF
> > > TRANSPARENCY 100
> > > PROJECTION
> > > 'proj=longlat'
> > > 'ellps=WGS84'
> > > 'datum=WGS84'
> > > 'no_defs'
> > > ''
> > > END
> > > CLASS
> > > NAME 'WaterBody'
> > > MAXSCALEDENOM 2000000
> > > MINSCALEDENOM 1500000
> > > STYLE
> > > SYMBOL 0
> > > SIZE 2
> > > OUTLINECOLOR 0 0 0
> > > COLOR 150 123 90
> > > END
> > > END
> > > END
> > >
> > > 1)Pls tell me whether I hav added the things at the correct place.
> > > 2) Can I also add it within the layer properties?
> > > 3) I find that the layers are being added at PageLoad.This
> > I found out
> > > by looking at the number of items being added at the bottom left
> > > corner of IE. The number of items has nearly doubled due to the
> > > addition of the 3 layers. Is there any way by which I can
> stop the
> > > layers from being added at PageLoad i.e they should be
> > added only when
> > > the desired scale is reached.
> > >
> > > 4) How to use TileCache or GeoWebCache i.e js code?
> > >
> > > Thanks again.
> > >
> > > Fawcett, David wrote:
> > >>
> > >> I assume the 'M' stands for million.
> > >>
> > >> If you want the layer to be only visible when 'zoomed in' beyond
> > >> 1:2M, I would set a MAXSCALEDENOM of 2000000.
> > >>
> > >> If you want the layer to be only visible when 'zoomed
> out' beyond
> > >> 1:2M, I would set a MINSCALEDENOM of 2000000.
> > >>
> > >> If you only want the layer to be visible between resolutions of
> > >> 1:100000 and 1:200000, you would set: both MINSCALEDENOM
> > 100000 and
> > >> MAXSCALEDENOM 200000
> > >>
> > >> These values go in either a LAYER or CLASS of LAYER in
> > your MapServer map
> > >> file.
> > >>
> > >>
> > >> -----Original Message-----
> > >> From: mapserver-users-bounces at lists.osgeo.org
> > >> [mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf
> > Of sunny74
> > >> Sent: Friday, August 28, 2009 8:45 AM
> > >> To: mapserver-users at lists.osgeo.org
> > >> Subject: Re: [mapserver-users] turning on layers at a
> > particular zoom
> > >> level
> > >>
> > >>
> > >>
> > >> Hi,
> > >>
> > >> Thanks for your reply.
> > >> I went thru the link and read about
> > MAXSCALEDENOM/MINSCALEDENOM. So
> > >> MINSCALEDENOM is the minimum scale level at which a layer
> > will become
> > >> visible. But I am a bit confused.When the map loads for
> the first
> > >> time it has a zoom level of 7 as given in the code below.
> > >>
> > >> map.setCenter(new OpenLayers.LonLat(74.25, 20.35), 7);
> > >>
> > >> In terms of scale it is showing 1:3M.
> > >> What is M?
> > >> If I increase the zoom level i.e do zoom in, scale becomes
> > 1:856K and
> > >> 1:256K etc i.e scale decreases. So If want a layer to be
> > visible at a
> > >> scale level of 1:2M what do I write in the mapfile?
> > >>
> > >> How to use TileCache or GeoWebCache?Pls give the js code.
> > >>
> > >>
> > >> Rahkonen Jukka wrote:
> > >>>
> > >>> Hi,
> > >>>
> > >>> Mapserver is somehow documented, about adjusting visibility
> > >>> according to scale, try to find MAXSCALEDENOM/MINSCALEDENOM from
> > >>> http://www.mapserver.org/mapfile/layer.html#index-21
> > >>>
> > >>> Mapserver does not do caching but you can use for examply
> > TileCache
> > >>> or GeoWebCache between your clients and Mapserver.
> > >>>
> > >>> -Jukka Rahkonen-
> > >>>
> > >>>
> > >>>
> > >>>> -----Alkuperäinen viesti-----
> > >>>> Lähettäjä: mapserver-users-bounces at lists.osgeo.org
> > >>>> [mailto:mapserver-users-bounces at lists.osgeo.org]
> Puolesta sunny74
> > >>>> Lähetetty: 28. elokuuta 2009 14:53
> > >>>> Vastaanottaja: mapserver-users at lists.osgeo.org
> > >>>> Aihe: [mapserver-users] turning on layers at a particular zoom
> > >>>> level
> > >>>>
> > >>>>
> > >>>> DEar Friends,
> > >>>>
> > >>>> I have 12 layers in my map and it is taking tooooo long to
> > >>>> load.Therefore I decided to turn on only 2 layers at Page Load.
> > >>>>
> > >>>> Rest of the layers I want to turn on at a particular zoom
> > >>>> level.How can I check the zoom level and turn on these layers.
> > >>>>
> > >>>> How can make the map load faster especially on page
> > reload? Is it
> > >>>> possible to cache the map or is there some other technique?
> > >>>>
> > >>>> Thanks for ur reply.
> > >>>>
> > >>>> --
> > >>>> View this message in context:
> > >>>> http://n2.nabble.com/turning-on-layers-at-a-particular-zoom-le
> > >>>> vel-tp3534156p3534156.html
> > >>>> Sent from the Mapserver - User mailing list archive at
> > Nabble.com.
> > >>>> _______________________________________________
> > >>>> mapserver-users mailing list mapserver-users at lists.osgeo.org
> > >>>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
> > >>>>
> > >>> _______________________________________________
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> > >>> mapserver-users at lists.osgeo.org
> > >>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
> > >>>
> > >>>
> > >>
> > >> --
> > >> View this message in context:
> > >>
> >
> http://n2.nabble.com/turning-on-layers-at-a-particular-zoom-level-tp3
> > >> 534156p3534743.html Sent from the Mapserver - User mailing list
> > >> archive at Nabble.com.
> > >> _______________________________________________
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> > >> http://lists.osgeo.org/mailman/listinfo/mapserver-users
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> > >>
> > >>
> > >
> > > --
> > > View this message in context:
> > >
> >
> http://n2.nabble.com/turning-on-layers-at-a-particular-zoom-level-tp35
> > > 34156p3540787.html Sent from the Mapserver - User mailing
> > list archive
> > > at Nabble.com.
> > > _______________________________________________
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> > >
> > >
> >
> > --
> > View this message in context:
> > http://n2.nabble.com/turning-on-layers-at-a-particular-zoom-le
> > vel-tp3534156p3566414.html
> > Sent from the Mapserver - User mailing list archive at Nabble.com.
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