[OpenLayers-Users] Ovewriting previous map

[Andreas Hocevar]

Surya Tarigan wrote:
>
> Dear Andreas,
>  
> I have removed "var" from:
>  
> > var map = new OpenLayers.Map('map', options );
> it stilt  doesn't work, firebug give 2 error messages:
>  
> 1) header is null -
> header.style.width=(getWindowWidth()-20) + "px";\r\n
>  
> (I think this error is not critical, it is from resize() function of TMS)
>  
>  
> 2) map is undefined in go() function
>

Maybe because you call go() before init()? To make sure, you can also 
define var outside the go and init functions:

<script>
...
var map;
function init() {}
function go() {}
...
</script>

Just look at the OpenLayers examples, there are many with forms and do 
just about the same...

Regards,
Andreas.

>  
> map.setCenter(new OpenLayers.Lonlat(longitude, latitude),5)\r\n
>  
> ( I have fixed zoom value to 5)
>  
> could you please give me further suggestion,
>  
> kind regards,
>  
> surya
>
> --- On *Tue, 9/8/09, Andreas Hocevar /<ahocevar at opengeo.org>/* wrote:
>
>
>     From: Andreas Hocevar <ahocevar at opengeo.org>
>     Subject: Re: [OpenLayers-Users] Ovewriting previous map
>     To: "Surya Tarigan" <surya.tarigan at yahoo.com>
>     Cc: users at openlayers.org
>     Date: Tuesday, September 8, 2009, 10:00 AM
>
>     Hi,
>
>     see my comments inline, and use a javascript debugger like Firebug for
>     Firefox to see what is going on.
>
>     Surya Tarigan wrote:
>     >
>     > Formerly,  I call go() function (see snippet below) which
>     handles the
>     > map.setCenter, it seems that this function doesn't react to the
>     change
>     > of lonlat value in drop down list. I have two layers, my base
>     layer is
>     > a big quickbird image tiled into 6 zoom levels and other layer
>     is WMS
>     > layer with hundreds of river names. Drop down list should help
>     user to
>     > pin point selected river in the quickbird image.
>     > 
>     > When I call init() function it doeas react, but create a series
>     of map
>     > which doesn't overwrite each other. I certainly do not want to
>     create
>     > new map every time I change lonlat value, it will double/tripple
>     > processing  time.
>     > 
>     > 
>     > 
>     > 
>     > -----------------
>     > 
>     > function init(){
>     > 
>     > var options = {
>     > theme: null,
>     > maxExtent: new OpenLayers.Bounds(225389.527874, 9627709.46055,
>     > 244613.714826, 9639853.34683 ),
>     > maxResolution: 103.338482,
>     > projection: 'EPSG:4326',
>     > units: 'm',
>     > controls: [
>     > new OpenLayers.Control.LayerSwitcher(),
>     > new OpenLayers.Control.MousePosition(),
>     > new OpenLayers.Control.PanZoom(),
>     > new OpenLayers.Control.ScaleLine()
>     > ]
>     > }; //option
>     > 
>     > var mapBounds = new OpenLayers.Bounds( 225389.527874, 9627709.46055,
>     > 244613.714826, 9639853.34683 );
>     > 
>     > var map = new OpenLayers.Map('map', options );
>     >
>
>     map is local to the init function here, so it won't be available
>     in the
>     go() function. Remove "var" to make it global.
>
>     > 
>     > var layer = new OpenLayers.Layer.TMS( "TMS Layer","",
>     > { url: '', serviceVersion: '.', layername: '.', alpha: true,
>     > type: 'png', getURL: overlay_getTileURL });
>     > 
>     > var river = new OpenLayers.Layer.WMS(
>     > "topp:sungai_nr - river", "http://localhost:8080/geoserver/wms",
>     > {layers: 'topp:sungai_nr',
>     > format: 'image/png',transparent:'true'},{'opacity': 0.2});
>     > 
>     > map.addLayers([layer, river]);
>     > 
>     > map.addControl(new OpenLayers.Control.Scale($('scale')));
>     > map.setCenter(new OpenLayers.LonLat(231064.944,9631783.43),4);
>     > } //function init
>     > 
>     > function go() {
>     > //Get the selected value for lonlat
>     > var lonlat =
>     document.getElementById('lonlat').options[document.getElementById('lonlat').selectedIndex].value;
>     > // Parse the lonlat to get the longitude
>     > var longitude = lonlat.substring(0,lonlat.indexOf(','));
>     > // Parse the lonlat to get the latitude
>     > var latitude =
>     lonlat.substring(lonlat.indexOf(',')+1,lonlat.length);
>     > // set Center
>     > map.setCenter(new OpenLayers.LonLat(longitude,latitude),zoom);
>     >
>
>     The above will fail because your map is not known to the go()
>     function.
>     See my comment above in the init function.
>
>     Also, save yourself some lines of code: instead of calculating
>     longitude
>     and latitude like above, use
>
>     map.setCenter(OpenLayers.LonLat.fromString(lonlat);
>
>     Regards,
>     Andreas.
>
>     -- 
>     Andreas Hocevar
>     OpenGeo - http://opengeo.org/
>     Expert service straight from the developers.
>
>
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>
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-- 
Andreas Hocevar
OpenGeo - http://opengeo.org/
Expert service straight from the developers.