Perform spatial operations

View inAndroidFormsUWPWPFWinUIiOSView on GitHub

Find the union, intersection, or difference of two geometries.

Image of perform spatial operations

Use case

The different spatial operations (union, difference, symmetric difference, and intersection) can be used for a variety of spatial analyses. For example, government authorities may use the intersect operation to determine whether a proposed road cuts through a restricted piece of land such as a nature reserve or a private property. When these operations are chained together, they become even more powerful. An analysis of food deserts within an urban area might begin by union-ing service areas of grocery stores, farmer's markets, and food co-ops. Taking the difference between this single geometry of all services areas and that of a polygon delineating a neighborhood would reveal the areas within that neighborhood where access to healthy, whole foods may not exist.

How to use the sample

The sample provides an option to select a spatial operation. When an operation is selected, the resulting geometry is shown in red. The 'reset operation' button undoes the action and allow selecting a different operation.

How it works

  1. Create a GraphicsOverlay and add it to the MapView.
  2. Define a PointCollection of each Geometry.
  3. Add the overlapping polygons to the graphics overlay.
  4. Perform spatial relationships between the polygons by using the appropriate operation:
    • GeometryEngine.Union(geometry1, geometry2) - This method returns the two geometries united together as one geometry.
    • GeometryEngine.Difference(geometry1, geometry2) - This method returns any part of Geometry2 that does not intersect Geometry1.
    • GeometryEngine.SymmetricDifference(geometry1, geometry2) - This method returns any part of Geometry1 or Geometry2 which do not intersect.
    • GeometryEngine.Intersection(geometry1, geometry2) - This method returns the intersection of Geometry1 and Geometry2.
  5. Use the geometry that is returned from the method call to create a new Graphic and add it to the graphics overlay for it to be displayed.

Relevant API

  • Geometry
  • GeometryEngine
  • GeometryEngine.Difference
  • GeometryEngine.Intersection
  • GeometryEngine.SymmetricDifference
  • GeometryEngine.Union
  • Graphic
  • GraphicsOverlay

Tags

analysis, combine, difference, geometry, intersection, merge, polygon, union

Sample Code

SpatialOperations.xamlSpatialOperations.xamlSpatialOperations.xaml.cs
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<UserControl x:Class="ArcGISRuntime.WinUI.Samples.SpatialOperations.SpatialOperations"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:esriUI="using:Esri.ArcGISRuntime.UI.Controls">
    <Grid>
        <esriUI:MapView x:Name="MyMapView" />
        <Border Width="275"
                Margin="30"
                Padding="10"
                HorizontalAlignment="Center"
                VerticalAlignment="Top"
                Background="White"
                BorderBrush="Black"
                BorderThickness="1">
            <StackPanel>
                <TextBlock Text="Select a spatial operation:" />
                <ComboBox x:Name="SpatialOperationComboBox"
                          Width="253"
                          Margin="0,5"
                          SelectionChanged="SpatialOperationComboBox_SelectionChanged" />
                <Button x:Name="ResetOperationButton"
                        Width="253"
                        Click="ResetOperationButton_Click"
                        Content="Reset operation" />
            </StackPanel>
        </Border>
    </Grid>
</UserControl>

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