确定地图中草图叠加层下的点

Question

我有一张带有不同点的 GraphicsOverlay 的地图。我让用户能够通过使用 SketchEditor 绘制多边形来选择点的子集。如何确定哪些点已被选中？

这是设置地图的代码子集：

private GraphicsOverlay graphicsOverlayLow;

// Graphics overlay to host sketch graphics
private GraphicsOverlay _sketchOverlay;

var symbolLow = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.Circle, Colors.Green, 10d);

graphicsOverlayLow = new GraphicsOverlay() { Renderer = new SimpleRenderer(symbolLow) };

foreach (var graphic in graphicListLow)  // graphicListLow is a List of Points
    graphicsOverlayLow.Graphics.Add(graphic);

MyMapView.GraphicsOverlays = new GraphicsOverlayCollection();

MyMapView.GraphicsOverlays.Add(graphicsOverlayLow);

_sketchOverlay = new GraphicsOverlay();
MyMapView.GraphicsOverlays.Add(_sketchOverlay);

我有两个按钮，一个用于开始绘制多边形，一个用于在完成后单击（这遵循 SketchEditor 的 esri 示例）。启动代码如下：

private async void SelectButton_Click(object sender, RoutedEventArgs e)
{
    try
    {
        // Let the user draw on the map view using the chosen sketch mode
        SketchCreationMode creationMode = SketchCreationMode.Polygon;
        Esri.ArcGISRuntime.Geometry.Geometry geometry = await MyMapView.SketchEditor.StartAsync(creationMode, true);

        // Create and add a graphic from the geometry the user drew
        Graphic graphic = CreateGraphic(geometry);
        _sketchOverlay.Graphics.Add(graphic);
    }
    catch (TaskCanceledException)
    {
        // Ignore ... let the user cancel drawing
    }
    catch (Exception ex)
    {
        // Report exceptions
        MessageBox.Show("Error drawing graphic shape: " + ex.Message);
    }
}


private Graphic CreateGraphic(Esri.ArcGISRuntime.Geometry.Geometry geometry)
{
    // Create a graphic to display the specified geometry
    Symbol symbol = null;
    switch (geometry.GeometryType)
    {
        // Symbolize with a fill symbol
        case GeometryType.Envelope:
        case GeometryType.Polygon:
            {
                symbol = new SimpleFillSymbol()
                {
                    Color = Colors.Red,
                    Style = SimpleFillSymbolStyle.Solid,
                };
                break;
            }

这里是例程的处理程序，当用户单击表示他们已完成绘制多边形的按钮时调用该例程。这是我要确定哪些点已被选中的地方。

private void CompleteButton_Click(object sender, RoutedEventArgs e)
{
    // Cancel execution of the sketch task if it is already active
    if (MyMapView.SketchEditor.CancelCommand.CanExecute(null))
    {
        MyMapView.SketchEditor.CancelCommand.Execute(null);
    }
}

请注意，我使用的是 100.4 SDK for WPF。

Answer 1

这可以通过空间查询来完成。您必须使用草图编辑器返回的几何图形，并使用几何过滤器在图层上执行空间查询。

Esri.ArcGISRuntime.Geometry.Geometry geometry = await MyMapView.SketchEditor.StartAsync(creationMode, true);

var queryparameters = new QueryParameters()
            {
                Geometry = geometry,
                SpatialRelationship = SpatialRelationship.Intersects
            };
await layer.SelectFeaturesAsync(queryparameters, Esri.ArcGISRuntime.Mapping.SelectionMode.New);

Answer 2

您可以使用 GeometryEngine.Intersects 方法检查点图形何时相交、触摸、交叉选择多边形。 https://community.esri.com/message/826699-re-determine-points-that-are-under-a-sketchoverlay-in-a-map?commentID=826699#comment-826699