# Perform spatial operations

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

## 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
Use dark colors for code blocksCopy
``````﻿<UserControl
x:Class="ArcGIS.UWP.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 Background="White" BorderBrush="Black" BorderThickness="1"
HorizontalAlignment="Center" VerticalAlignment="Top"
<StackPanel>
<TextBlock Text="Select a spatial operation:"/>
<ComboBox x:Name="SpatialOperationComboBox"
Margin="0,5"
SelectionChanged="SpatialOperationComboBox_SelectionChanged" Width="253"/>
<Button x:Name="ResetOperationButton"
Content="Reset operation"
Click="ResetOperationButton_Click" Width="253"/>
</StackPanel>
</Border>
</Grid>
</UserControl>``````