[GIS] OpenLayers 3 zoom factor

openlayers

I know we can create map with a zoom factor like:

map = new ol.Map({
target: 'container',
layers: [
    layer
],
view: new ol.View({
    maxResolution: res,
    extent: ext,
    zoomFactor: factor
}),
controls: [
   new ol.control.Zoom()
]

});

But is there any way to change this zoom factor on the fly? I want to make custom control to set that. Any function like map.getView().setZoomFactor() ?

Best Answer

Yes, it's setZoom() .

In your case: map.getView().setZoom(x)

Always a good idea to check the API for such simple things first :) .

EDIT:

My bad, misunderstood. No, you cannot alter the zoomfactor after initialization right now, just as you can't change a lot of view constraints programmatically. The established workflow is to recreate the view with the new setting and then set that on the map. However, it is being worked on and might come sooner or later ( latest updates of OL gave us setMaxZoom/setMinZoom, at least!)

Related Solutions

[GIS] Openlayers 3 WMS custom projection wrong extent

You should leave your map in the default google coordinate EPSG: 3857 :

  map = new ol.Map({
            loadTilesWhileAnimating: true,
            // adds default controls
            controls: ol.control.defaults().extend([
                //adds a scalebar
                new ol.control.ScaleLine({
                    // units: ol.control.ScaleLineUnits.METRIC
                }),
                new ol.control.ZoomSlider({
                })

                ]),
            //rendering params
            target: dom_id, //Ext.get(idDiv),
            layers: baseLayers,
            renderer: 'canvas',
            view: new ol.View({
                projection: ol.proj.get('EPSG:3857'),


            })
        });

And param your WMS tile with its correct projection

// Aerial Tile Layer
        var aerialLayer = new ol.layer.Tile({
            title: "Aerial",
            source: new ol.source.TileWMS({
                url: 'http://server01:8080/geoserver/sf/wms',
                params: {
                    'LAYERS': 'sf:TEST01',
                    'STYLES': ''
                },
                serverType: 'geoserver',
                projection: ol.proj.get('EPSG:3006'),
            })
        });

That should work !

[GIS] Get/Define extent of ol.source.tile xyz

So the solution I found to this was to add a check for another value on the layer. In this case, the value of 'sub'. This allowed me to perform a check as to whether the layer source had a defined extent. If the extent was found, I looked up the minZoom value, got the centre coordinate of the extent, then set the view to this.

The functionality seemed to break if I checked for the extent property on a non-defined source so the check for the 'sub' property negated this. It's been a long road from locating a quadkey function, working out how to apply this to a custom xyz url, finding out how to transform the projection of the extent then looking up the zoom and setting a new view; not to mention creating a select menu from the layers, but the effort was definitely worth it.

I'm sure my code looks a little ropey to most people and I'll have the opportunity to refine it later but thanks to anyone who helped along the way. @AlvinLindstam, @JonatasWalker and @Pavlos have all helped me to better understand how all of this fits together. For the benefit of anyone looking to do something similar, I'll post the code below and here is a link to the fiddle.

var sub = layers[s].get('sub'); // where layers[s] is the result of a layer search
var extent;
    if (title == selectedValue) {   
        if (sub == undefined) {
           layers[s].setVisible(true);
        }
        if (sub == 'premium') {
                var duration = 2000;
                var start = +new Date();
                var view = map.getView();
                var pan = ol.animation.pan({
                    duration: duration,
                    //easing: eval(ol.easing.inAndOut),
                    source: (view.getCenter()),
                    start: start
                });
                var bounce = ol.animation.bounce({
                    duration: duration,
                    resolution: 4 * view.getResolution(),
                    start: start
                });

                // Add animation to the render pipeline
                map.beforeRender(pan, bounce);

                extent = layers[s].getExtent();
                console.log(extent);
                layerZoom = layers[s].getProperties().minZoom;
                var sourceCentre = ol.extent.getCenter(extent);
                view.setCenter(sourceCentre);
                view.setZoom(layerZoom);
                layers[s].setVisible(true);
            }

Best Answer

Related Solutions

[GIS] Openlayers 3 WMS custom projection wrong extent

[GIS] Get/Define extent of ol.source.tile xyz

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