MapViewAutomationPeer zoom based on rectangle size?

Question

Hi All,

I am trying to build basic navigation control on map.On button click I want to draw rectangle and perform zoom in/out operation.

I found MapViewAutomationPeer clss to control map zoom but it doesn't work as expected.

ZoomInAnimated/ZoomOutAnimated only zoom to center point. No option for scale.

What is the best approach to zoom using rectangle size? i.e. if the rectangle is bigger than zoom to less scale else on higher side.

I am using WPF 100.6

Any help would be appreciated.

Regards,

Prashant

PrashantKirpan · Answer

Hi Morten,

I tried to calculate values to zoom out rectangle but not working as expected. Is it possible for you to provide any sample formula for below solution.

The simplest would be just to take the current map-scale, and multiple it by the relative width between the view size and the rectangle size, and then zoom to that.

Any help would be appreciated,

Regards,

Prashant

SomeGISGuy · Answer

For zoom-out you'd have to calculate the 'opposite' rectangle, which granted isn't straight-forward. Typically you'd expand around a location inside the rectangle by a certain amount relative to the size of the rectangle (a smaller rectangle would typically mean zoom out more). It's a bit of math, but not horrible, so play with a few values and see what works for you. The simplest would be just to take the current map-scale, and multiple it by the relative width between the view size and the rectangle size, and then zoom to that.

PrashantKirpan · Answer

Hi Morten,

Yes, this is working in case of zoom-In but how to implement zoom-Out?

I tried to below code for zoom out but not sure how to determine zoom level i.e. for small rectangle zoom out to lowest zoom level.

Geometry geometry = await MpView.SketchEditor.StartAsync(SketchCreationMode.Rectangle, false);

var point = MpView.LocationToScreen(geometry.Extent.GetCenter());
 Esri.ArcGISRuntime.UI.Controls.MapViewAutomationPeer peer = Esri.ArcGISRuntime.UI.Controls.MapViewAutomationPeer.FromElement(MpView) as Esri.ArcGISRuntime.UI.Controls.MapViewAutomationPeer;
 peer.ZoomOutAnimated(point);

Working zoom in code as you suggested:

Geometry geometry = await MpView.SketchEditor.StartAsync(SketchCreationMode.Rectangle, false);

await MpView.SetViewpointGeometryAsync(geometry.Extent);

Regards,

Prashant