Analyze viewshed (geoprocessing)

Calculate a viewshed using a geoprocessing service, in this case showing what parts of a landscape are visible from points on mountainous terrain.

Use case

A viewshed is used to highlight what is visible from a given point. A viewshed could be created to show what a hiker might be able to see from a given point at the top of a mountain. Equally, a viewshed could also be created from a point representing the maximum height of a proposed wind turbine to see from what areas the turbine would be visible.

How to use the sample

Tap the map to see all areas visible from that point within a 15km radius. Clicking on an elevated area will highlight a larger part of the surrounding landscape. It may take a few seconds for the task to run and send back the results.

How it works

1. Create a GeoprocessingTask object with the URL set to a geoprocessing service endpoint.
2. Create a FeatureCollectionTable object and add a new Feature object whose geometry is the viewshed's observer Point.
3. Make a GeoprocessingParameters object passing in the observer point.
4. Use the geoprocessing task to create a GeoprocessingJob object with the parameters.
5. Start the job and wait for it to complete and return a GeoprocessingResult object.
6. Get the resulting GeoprocessingFeatures object.
7. Iterate through the viewshed features to use their geometry or display the geometry in a new Graphic object.

Relevant API

• FeatureCollectionTable
• GeoprocessingFeatures
• GeoprocessingJob
• GeoprocessingParameters
• GeoprocessingResult
• GeoprocessingTask

Tags

geoprocessing, heat map, heatmap, viewshed

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage x:Class="ArcGISRuntime.Samples.AnalyzeViewshed.AnalyzeViewshed"
             xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:esriUI="clr-namespace:Esri.ArcGISRuntime.Xamarin.Forms;assembly=Esri.ArcGISRuntime.Xamarin.Forms">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="auto" />
            <RowDefinition Height="*" />
        </Grid.RowDefinitions>
        <Label Grid.Row="0"
               Margin="10,0,0,0"
               Text="Click a location on the map to perform the viewshed analysis." />
        <esriUI:MapView x:Name="MyMapView" Grid.Row="1" />
        <ActivityIndicator x:Name="MyActivityIndicator"
                           Grid.Row="1"
                           HorizontalOptions="CenterAndExpand"
                           IsVisible="False"
                           VerticalOptions="CenterAndExpand" />
    </Grid>
</ContentPage>