[OpenLayers-Dev] Set map extent to extent of a layer

Mon Oct 26 11:39:03 EDT 2009

I am having trouble setting the extent of my map to the extent of a layer.
The code below adds a Google base map and a WKT layer to the map and
correctly projects the polygon. 

However, I need to set the map center and scale so that the layer is
correctly positioned on the map. Essentially I want to set the map extent =
layer extent. 

I believe I am using the two lines below incorrectly

var bounds = new OpenLayers.Bounds(thrvec.getExtent);

alert (bounds.toString);

Can someone correct this code or provide me an alternate solution. Thanks in
advance!

Clark

Extent.js

______________________________________________________________

function init() {

  var proj = new OpenLayers.Projection("EPSG:900913");

  var display = new OpenLayers.Projection("EPSG:4326"); 

  var map = new OpenLayers.Map("map", {projection: proj, displayProjection:
display});

  map.addControl(new OpenLayers.Control.MousePosition());

  var wkt = new OpenLayers.Format.WKT({'internalProjection': proj,
'externalProjection': display});

  var gphy=new OpenLayers.Layer.Google("Google", {type: G_HYBRID_MAP,
numZoomLevels: 20, 'sphericalMercator': true, 'maxExtent': new
OpenLayers.Bounds(-20037508.34,-20037508.34,20037508.34,20037508.34)});

  gphy.setIsBaseLayer(true);

  map.addLayers([gphy]);

// WKT

  str='POLYGON((-118.460185 34.095586,-118.458857 34.095874,-118.457521
34.095991,-118.456222 34.095947,-118.455012 34.095732,-118.453946
34.095366,-118.453056 34.094858,-118.452386 34.094218,-118.451945
34.093481,-118.451766 34.092677,-118.451837 34.091830,-118.452179
34.090969,-118.452769 34.090148,-118.453576 34.089374,-118.454575
34.088685,-118.455735 34.088115,-118.457001 34.087681,-118.458329
34.087392,-118.459664 34.087275,-118.460964 34.087320,-118.462163
34.087525,-118.463239 34.087900,-118.464118   34.088408,-118.464799
34.089048,-118.465240 34.089785,-118.465420 34.090589,-118.465338
34.091436,-118.464996 34.092288,-118.464417 34.093118,-118.463610
34.093892,-118.462600 34.094572,-118.461451 34.095152,-118.460185
34.095586))';

  features=wkt.read([str]);           

  var style1 ={fillColor: '#FFFF33', fillOpacity: .5};

  var thrvec=new OpenLayers.Layer.Vector('WKT',  {style: style1});

  map.addLayers([thrvec]);

  thrvec.addFeatures(features);

  var bounds = new OpenLayers.Bounds(thrvec.getExtent);

  alert (bounds.toString);

  bounds.transform(display,proj);

  map.zoomToExtent(bounds)

  var point = new OpenLayers.LonLat(-118.458591, 34.091633);

  point.transform(display,proj);

  map.setCenter(point,13);

}

HTML

______________________________________________________________

<html xmlns="http://www.w3.org/1999/xhtml">

  <head>

    <script
src='http://maps.google.com/maps?file=api&amp;v=2&amp;key=ABQIAAAAjpkAC9ePGe
m0lIq5XcMiuhR_wWLPFku8Ix9i2SXYRVK3e45q1BQUd_beF8dtzKET_EteAjPdGDwqpQ'></scri
pt>

    <script src="OpenLayers.js"></script>

    <script src="extent.js"></script>

    <link rel="stylesheet" href="style.css" type="text/css" />

  </head>

  <body onload="init()">

    <div id="map" style="width: 671px; height: 461px; vertical-align:
middle; horizontal-align: center;"></div>

  </body>

</html>

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