[mapserver-users] turning on layers at a particular zoom level
sunny74
sb.ray at hotmail.com
Wed Sep 2 08:30:30 EDT 2009
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.
>>>>
>>>> --
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>>>> vel-tp3534156p3534156.html
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>>
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