change it to be
var zoom = map.getZoom();
console.log('zoom is ' + zoom);
if (zoom < clusterMaxZoom)
so that you can see what the actual zoom levels are.
On 2011-02-16, at 9:54 AM, Mihai Visan wrote:
> Hi Paul,
>
> from what I know about OpenLayers your code is what I'm looking for, but I
> can't make the event working. What is interesting is that if I change what is
> with red it deactivate cluster strategy no matter the zoom level.
>
> map.events.register("move", null, function() { // #2, #3 respond to map
> extent change
> // disable cluster when zoom greater than threshold
> if (map.getZoom() < clusterMaxZoom) { // #2.1 how to read current
> zoom
> clusterStrategy.deactivate(); // #2.2 how to disable cluster
> strategy
> } else {
> clusterStrategy.activate();
> }
> });
>
> Help me please.
>
> Here is my code:
>
> ....................................................................
>
> <html>
> <head>
> <title>OpenLayers Test</title>
> <script type="text/javascript" src="js/OpenLayers.js"></script>
> <script defer="defer" type="text/javascript">
> function init(){
>
> // styles for cluster strategy
> var style = new OpenLayers.Style({
> fillColor: "${fill_color}",
> fillOpacity: 0.4,
> pointRadius: "${radius}",
> strokeColor: "${stroke_color}",
> strokeOpacity: 1,
> strokeWidth: 1
> },
> {
> context: {
> radius: function(feature) {
> var pix = 8;
> if(feature.cluster) {
> pix = Math.min(feature.attributes.count, 11)
> + 8;
> }
> return pix;
> },
> fill_color: function(feature) {
> if(feature.cluster) {
> maxImportance = 0;
> for(var c = 0; c <
> feature.cluster.length; c++) {
> i =
> feature.cluster[c].attributes.importance;
> if(i > maxImportance) {
> maxImportance = i;
> mainFeature = c;
> }
> }
> feature.attributes.fillColor =
> feature.cluster[mainFeature].attributes.fillColor;
> }
> return feature.attributes.fillColor;
> },
> stroke_color: function(feature) {
> if(feature.cluster) {
> maxImportance = 0;
> for(var c = 0; c <
> feature.cluster.length; c++) {
> i =
> feature.cluster[c].attributes.importance;
> if(i > maxImportance) {
> maxImportance = i;
> mainFeature = c;
> }
> }
> feature.attributes.strokeColor =
> feature.cluster[mainFeature].attributes.strokeColor;
> }
> return feature.attributes.strokeColor;
> }
> }
> });
>
> /* Creating the Map Viewer */
> /*In order to create the viewer, you must first create a map. The
> OpenLayers.Map constructor requires one argument: This argument must either
> be an HTML Element, or the ID of an HTML element. This is the element in
> which the map will be placed.*/
> var map = new OpenLayers.Map("map", {
> controls: [
> new OpenLayers.Control.Navigation(),
> new OpenLayers.Control.PanPanel(),
> new OpenLayers.Control.ZoomPanel(),
> new OpenLayers.Control.LayerSwitcher() /* Open the switch
> layers panel */
> ],
> maxResolution: 'auto',
> numZoomLevels: 6 // maximum zoom
> });
>
> /*Map Constructor*/
> /* The next step to creating a viewer is to add a basic layer to the
> Map. */
> var basicMapLayer = new OpenLayers.Layer.Image(
> "Map Image",
> "images/maps/MapImage.jpg",
> new OpenLayers.Bounds(0, 0, 510, 510),
> new OpenLayers.Size(510, 510)
> );
>
> /* Adding an Multipoint Vector Layer with cluster strategy */
> var clusterStrategy = new OpenLayers.Strategy.Cluster({distance: 20});
>
> var monuments = new OpenLayers.Layer.Vector("Monuments", {
> strategies: [clusterStrategy],
> styleMap: new OpenLayers.StyleMap({"default": style})
> });
>
> // cluster threshold
> var clusterMaxZoom = 2; // maximum zoom is 6
>
> map.events.register("move", null, function() { // #2, #3 respond to map
> extent change
> // disable cluster when zoom greater than threshold
> if (map.getZoom() > clusterMaxZoom) { // #2.1 how to read current
> zoom
> clusterStrategy.deactivate(); // #2.2 how to disable cluster
> strategy
> } else {
> clusterStrategy.activate();
> }
> });
>
> var point_1 = new OpenLayers.Geometry.Point(270, 205);
> var point_1_Feature = new OpenLayers.Feature.Vector(point_1);
> point_1_Feature.attributes = {
> strokeColor: "#ffffff",
> fillColor: "#ffffff",
> importance: 9
> }
>
> var point_2 = new OpenLayers.Geometry.Point(263, 201);
> var point_2_Feature = new OpenLayers.Feature.Vector(point_2);
> point_2_Feature.attributes = {
> strokeColor: "blue",
> fillColor: "blue",
> importance: 3
> }
>
> var point_3 = new OpenLayers.Geometry.Point(260, 202);
> var point_3_Feature = new OpenLayers.Feature.Vector(point_3);
> point_3_Feature.attributes = {
> strokeColor: "yellow",
> fillColor: "yellow",
> importance: 5
> }
>
> var point_4 = new OpenLayers.Geometry.Point(261, 202);
> var point_4_Feature = new OpenLayers.Feature.Vector(point_4);
> point_4_Feature.attributes = {
> strokeColor: "yellow",
> fillColor: "yellow",
> importance: 5
> }
>
> var point_5 = new OpenLayers.Geometry.Point(263, 202);
> var point_5_Feature = new OpenLayers.Feature.Vector(point_5);
> point_5_Feature.attributes = {
> strokeColor: "yellow",
> fillColor: "yellow",
> importance: 5
> }
>
> /* Layer Constructor */
> /* In order to display the map, you must set a center and zoom level.
> In order to zoom to fit the map into the window, you can use the
> zoomToMaxExtent function, which will zoom as close as possible while still
> fitting the full extents within the window. */
> map.addLayers([basicMapLayer, monuments]);
> map.zoomToMaxExtent();
>
> // features for layer with cluster strategy must me declared after
> layer is added in order to work
> var monumentsFeature = new OpenLayers.Feature.Vector(
> new
> OpenLayers.Geometry.MultiPoint([point_1, point_2, point_3, point_4, point_5])
> );
> monuments.addFeatures([point_1_Feature, point_2_Feature,
> point_3_Feature, point_4_Feature, point_5_Feature]);
>
> // end of init function
> }
> </script>
> </head>
> <body onLoad="init()">
> <div style="width:100%; height:100%; border:#000 1px solid;
> background:#000000;" id="map"></div>
> </body>
> </html>
>
> ....................................................................
>
> -----Original Message-----
> From: Paul Spencer
> Sent: Wednesday, February 16, 2011 3:37 PM
> To: Mihai Visan
> Cc: OpenLayers User list
> Subject: Re: [OpenLayers-Users] cluster strategy
>
> I don't know your code but I would assume that you are looking for something
> like this:
>
> var map = new OpenLayers.Map('mapDiv', mapOptions);
> var clusterStrategy = new OpenLayers.Strategy.Cluster(clusterOptions);
> var layerOptions = {
> strategies: [clusterStrategy]
> };
> var vectorLayers = new OpenLayers.Layer.Vector('features', layerOptions);
>
> // cluster threshold
> var clusterMaxZoom = 10;
>
> map.events.register('move', null, function() { // #2, #3 respond to map
> extent change
> // disable cluster when zoom greater than threshold
> if (map.getZoom() > clusterMaxZoom) { // #2.1 how to read current zoom
> clusterStrategy.deactivate(); // #2.2 how to disable cluster strategy
> } else {
> clusterStrategy.activate();
> }
>
> // filter features based on bounding box
> var extent = map.getExtent(); // #3.1
>
> // reload features here, it depends on how you read your features in now
>
> });
>
> If you are not using a Protocol like WFS () with your layer then the BBOX
> strategy will have no effect and you will have to manually reload features
> using whatever mechanism you are using now.
>
> Cheers
>
> Paul
>
> On 2011-02-16, at 7:58 AM, Mihai Visan wrote:
>
> > Thanks Paul,
> >
> > I already read the documentation and all tutorial and user discusions I
> > could found.
> >
> > But I'm a week at javascript, so I could use some examples or tutorials I
> > could transform
> >
> > -----Original Message----- From: Paul Spencer
> > Sent: Wednesday, February 16, 2011 2:43 PM
> > To: Mihai Visan
> > Subject: Re: [OpenLayers-Users] cluster strategy
> >
> > Mihai, all of your questions have answers in the documentation ...
> >
> > On 2011-02-16, at 7:29 AM, Mihai Visan wrote:
> >
> >> 2. disable cluster strategy at certain zoom level.
> >> Problems: 2.1. I don’t know how to read current zoom
> >
> > http://dev.openlayers.org/releases/OpenLayers-2.10/doc/apidocs/files/OpenLayers/Map-js.html#OpenLayers.Map.getZoom
> >
> >> 2.2. I don’t know to disable cluster strategy
> >
> > http://dev.openlayers.org/releases/OpenLayers-2.10/doc/apidocs/files/OpenLayers/Strategy/Cluster-js.html#OpenLayers.Strategy.Cluster.deactivate
> >
> >>
> >> 3. use (BBOX strategy and) ajax to disable features outside visible bounds
> >> Problems: 3.1. I don’t know how to read visible bounds
> >
> > http://dev.openlayers.org/releases/OpenLayers-2.10/doc/apidocs/files/OpenLayers/Map-js.html#OpenLayers.Map.getExtent
> >
> >> 3.2. I don’t know how to integrate ajax with (BBOX
> >> and) mouse drag or zoom in/out
> >
> > http://dev.openlayers.org/releases/OpenLayers-2.10/doc/apidocs/files/OpenLayers/Map-js.html#OpenLayers.Map.EVENT_TYPES
> >
> > Cheers
> >
> > Paul
>
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