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How to use CenterAt()

#1

Hi,

I’m trying to center the map at one point using mapView.CenterAt (location). However, I’m getting the following message:

System.ArgumentOutOfRangeException: The input double value is out of range.
Parameter name: screenWidth

Also, my mapview has width and height equal to 0.

can anybody help me?

#2

Hi Marco,

Could you please let me know your scenario? Because it looks your map is invisible and you want to set the center point.

And in fact I hadn’t reproduced the exception by the test code as below, I think maybe you can directly set the CurrentExtent instead of use center at.

 public ActionResult DisplayASimpleMap()
    {
        Map map = new Map("Map1",
            new System.Web.UI.WebControls.Unit(0, System.Web.UI.WebControls.UnitType.Pixel),
            new System.Web.UI.WebControls.Unit(0, System.Web.UI.WebControls.UnitType.Pixel));
                   

        map.MapUnit = GeographyUnit.DecimalDegree;            
        map.CenterAt(0, 0);

        map.MapBackground = new BackgroundLayer(new GeoSolidBrush(GeoColor.FromHtml("#E5E3DF")));
        map.CustomOverlays.Add(new WorldMapKitWmsWebOverlay());

        return View(map);
    }

Regards，

Don

#3

Hi Don, how are you?

Thanks for answering.

I’m following the sample code I found on the wiki. Currently my code looks like this:

public class MainActivity : Activity
    {
        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);
            SetContentView(Resource.Layout.Main);

            string targetDirectory = (@"/mnt/sdcard/Android.Sample/GetStarted/");
            CopySampleData(targetDirectory);

            MapView mapView = FindViewById<MapView>(Resource.Id.MapView);
            mapView.MapUnit = GeographyUnit.DecimalDegree;

            ShapeFileFeatureLayer worldLayer = new ShapeFileFeatureLayer(Path.Combine(targetDirectory, "cntry02.shp"));
            worldLayer.ZoomLevelSet.ZoomLevel01.DefaultAreaStyle = AreaStyles.Country1;
            worldLayer.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;

            ShapeFileFeatureLayer eixoNicolas = new ShapeFileFeatureLayer(Path.Combine(targetDirectory + "eixo_nicolas.SHP"));
            eixoNicolas.RequireIndex = false;
            eixoNicolas.ZoomLevelSet.ZoomLevel01.DefaultLineStyle = LineStyles.CreateSimpleLineStyle(GeoColor.SimpleColors.Green, 5, true);
            eixoNicolas.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;

            LayerOverlay overlay = new LayerOverlay();
            overlay.Opacity = 0.8;
            overlay.Layers.Add(worldLayer);
            overlay.Layers.Add(eixoNicolas);

            mapView.Overlays.Add("EixoNicolas", overlay);

            mapView.CurrentExtent = new RectangleShape(5, 78, 30, 26);
        }

private void CopySampleData(string targetDirectory)
        {
            if (!Directory.Exists(targetDirectory))
            {
                Directory.CreateDirectory(targetDirectory);
                foreach (string filename in Assets.List("AppData"))
                {
                    Stream stream = Assets.Open("AppData/" + filename);
                    FileStream fileStream = File.Create(Path.Combine(targetDirectory, filename));
                    stream.CopyTo(fileStream);
                    fileStream.Close();
                    stream.Close();
                }
            }
        }

Is it possible to center the map according to real-world coordinates?

Regards.

#4

Hi Marco,

When I reply you last time, the post hadn’t shows it’s an Android question, so I reply you the code is our other product.

Because I hadn’t the environment today for Android, so maybe I will test that this Friday.

And if you want to find the correct value to set mapView.CurrentExtent, I think the code as below should be helpful.

        double scale = mapView.CurrentScale;
        PointShape point = new PointShape(0, 0); // Put your point here
        RectangleShape rect = new RectangleShape(point.X - 0.5, point.Y + 0.5, point.X + 0.5, point.Y - 0.5);

        // Please modify the parameter to make it works
        RectangleShape resultRectangle = ExtentHelper.ZoomToScale(scale, rect, mapView.MapUnit, mapView.Width, mapView.Height);
        mapView.CurrentExtent = resultRectangle;

Regards,

Don

#5

Hi Don,

I await your response.

I tried to use the code from your last reply and what I got was:

Unhandled Exception:
System.ArgumentOutOfRangeException: The input double value is out of range.
Parameter name: screenWidth

What can I do?

Thanks,

Marco

#6

Hi Marco,

Sorry that I was unable to recreate the problem on my end, also I tried the samples shown at http://wiki.thinkgeo.com/wiki/map_suite_android_edition#learning_samples, but seems like all works fine, would you please provide your ready-to-go sample for me ?

Thanks,
Johnny

#7

Hi Johnny, thanks for answering.

Sorry, I can’t.

#8

OK, Marco, I will try creating a demo to show how to call CenterAt and update it to you tomorrow. Now I’m out of office.

Regards,
Johnny

#9

Marco,

see demo attached,

helloworld_android.zip (1.5 MB)

2 options mentioned in the code, just like below:

  1. Option 1: change the currentExtent to accord the map to a real-world coordinate.
    mapView.CurrentExtent = new RectangleShape(5, 78, 30, 26);

  2. Option 2: use Center and Scale
    RunOnUiThread(() =>
    {
    ZoomLevelSet decimalDegreeZoomLevelSet = new ZoomLevelSet();
    PointShape center = new PointShape(30, 26);
    mapView.ZoomTo(center, decimalDegreeZoomLevelSet.ZoomLevel08.Scale);
    });

Thanks,
Johnny