ArcGIS Runtime SDK for .NET Samples

Change viewpoint

Change viewpoint


// Copyright 2016 Esri.
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
// You may obtain a copy of the License at:
// Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an 
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific 
// language governing permissions and limitations under the License.

using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.UI.Controls;
using Foundation;
using System;
using System.Collections.Generic;
using System.Linq;
using UIKit;

namespace ArcGISRuntime.Samples.ChangeViewpoint
        "Change viewpoint",
        "This sample demonstrates different ways in which you can change the viewpoint or visible area of the map.",
    public class ChangeViewpoint : UIViewController
        // Constant holding offset where the MapView control should start
        private const int yPageOffset = 60;

        private UIButton _viewpointsButton;

        // Create and hold reference to the used MapView
        private MapView _myMapView = new MapView();

        // Coordinates for London
        private MapPoint LondonCoords = new MapPoint(
            -13881.7678417696, 6710726.57374296, SpatialReferences.WebMercator);
        private double LondonScale = 8762.7156655228955;

        // Coordinates for Redlands
        private Polygon RedlandsEnvelope = new Polygon(
            new List<MapPoint>
                    new MapPoint(-13049785.1566222, 4032064.6003424),
                    new MapPoint(-13049785.1566222, 4040202.42595729),
                    new MapPoint(-13037033.5780234, 4032064.6003424),
                    new MapPoint(-13037033.5780234, 4040202.42595729)

        // Coordinates for Edinburgh
        private Polygon EdinburghEnvelope = new Polygon(
            new List<MapPoint>
                new MapPoint(-354262.156621384, 7548092.94093301),
                new MapPoint(-354262.156621384, 7548901.50684376),
                new MapPoint(-353039.164455303, 7548092.94093301),
                new MapPoint(-353039.164455303, 7548901.50684376)},

        // String array to store titles for the viewpoints specified above.
        private string[] titles = new string[]
            "Center & Scale",

        public ChangeViewpoint()
            Title = "Change viewpoint";
        public override void ViewDidLoad()

            // Create the UI, setup the control references and execute initialization 

        public override void ViewDidLayoutSubviews()
            // Setup the visual frame for the MapView
            _myMapView.Frame = new CoreGraphics.CGRect(0, 0, View.Bounds.Width, View.Bounds.Height);

            // Setup the visual frame for the Button
            _viewpointsButton.Frame = new CoreGraphics.CGRect(0, View.Bounds.Height - 40, View.Bounds.Width, 40);


        private void Initialize()
            // Create new Map with basemap and initial location
            Map myMap = new Map(Basemap.CreateTopographic());

            // Assign the map to the MapView
            _myMapView.Map = myMap;

        private void OnViewpointsButtonTouch(object sender, EventArgs e)
            // Initialize an UIAlertController
            UIAlertController viewpointAlert = UIAlertController.Create(
                "Select viewpoint", "", UIAlertControllerStyle.Alert);

            // Add actions to alert. Selecting an option set the new viewpoint
            viewpointAlert.AddAction(UIAlertAction.Create(titles[0], UIAlertActionStyle.Default, 
                async (action) =>
                    // Set Viewpoint using Redlands envelope defined above and a padding of 20
                    await _myMapView.SetViewpointGeometryAsync(RedlandsEnvelope, 20);
            viewpointAlert.AddAction(UIAlertAction.Create(titles[1], UIAlertActionStyle.Default, 
                async (action) =>
                    // Set Viewpoint so that it is centered on the London coordinates defined above
                    await _myMapView.SetViewpointCenterAsync(LondonCoords);
                    // Set the Viewpoint scale to match the specified scale 
                    await _myMapView.SetViewpointScaleAsync(LondonScale);
            viewpointAlert.AddAction(UIAlertAction.Create(titles[2], UIAlertActionStyle.Default, 
                async (action) =>
                    // Navigate to full extent of the first baselayer before animating to specified geometry
                    await _myMapView.SetViewpointAsync(
                        new Viewpoint(_myMapView.Map.Basemap.BaseLayers.First().FullExtent));
                    // Create a new Viewpoint using the specified geometry
                    var viewpoint = new Viewpoint(EdinburghEnvelope);
                    // Set Viewpoint of MapView to the Viewpoint created above and animate to it using a timespan of 5 seconds
                    await _myMapView.SetViewpointAsync(viewpoint, TimeSpan.FromSeconds(5));
            PresentViewController(viewpointAlert, true, null);

        private void CreateLayout()
            // Add a button at the bottom to show viewpoint choices
            _viewpointsButton = new UIButton(UIButtonType.Custom)
                BackgroundColor = UIColor.White

            // Create button to show map options
            _viewpointsButton.SetTitle("Viewpoints", UIControlState.Normal);
            _viewpointsButton.SetTitleColor(UIColor.Blue, UIControlState.Normal);
            _viewpointsButton.TouchUpInside += OnViewpointsButtonTouch;

            // Add MapView to the page
            View.AddSubviews(_myMapView, _viewpointsButton);

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