Map image layer tables

Find features in a spatial table related to features in a non-spatial table.

Use case

The non-spatial tables contained by a map service may contain additional information about sublayer features. Such information can be accessed by traversing table relationships defined in the service.

How to use the sample

Once the map image layer loads, a list view will be populated with comment data from non-spatial features. Tap on one of the comments to query related spatial features and display the first result on the map.

How it works

1. Create an ArcGISMapImageLayer with the URL of a map image service.
2. Load the layer and get one of its tables with imageLayer.Tables[index].
3. To query the table, create a QueryParameters object.You can set queryParameters.WhereClause to filter the request features.
4. Use table.QueryFeaturesAsync(parameters) to get a FeatureQueryResult object.
5. The FeatureQueryResult is an iterable, so simply loop through it to get each result Feature.
6. To query for related features, get the table's relationship info with table.LayerInfo.RelationshipInfos. This returns a list of RelationshipInfo objects. Choose which one to base your query on.
7. Now create RelatedQueryParameters passing in the RelationshipInfo. To query related features, use table.QueryRelatedFeaturesAsync(feature, relatedQueryParameters).
8. This returns a list of RelatedFeatureQueryResult objects, each containing a set of related features.

Relevant API

• ArcGISFeature
• ArcGISMapImageLayer
• Feature
• FeatureQueryResult
• QueryParameters
• RelatedFeatureQueryResult
• RelatedQueryParameters
• RelationshipInfo
• ServiceFeatureTable

Additional information

You can use arcGISMapImageLayer.LoadTablesAndLayersAsync() to recursively load all sublayers and tables associated with a map image layer.

Tags

features, query, related features, search

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<?xml version="1.0" encoding="utf-8" ?>
<ContentPage x:Class="ArcGISRuntime.Samples.MapImageLayerTables.MapImageLayerTables"
             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="160" />
            <RowDefinition />
        </Grid.RowDefinitions>
        <Grid Margin="10">
            <Grid.RowDefinitions>
                <RowDefinition Height="auto" />
                <RowDefinition Height="*" />
            </Grid.RowDefinitions>
            <Label Grid.Row="0" Text="Select a row to see the related feature:" />
            <ListView x:Name="CommentsListBox"
                      Grid.Row="1"
                      HeightRequest="140"
                      ItemSelected="CommentsListBox_SelectionChanged">
                <ListView.ItemTemplate>
                    <DataTemplate>
                        <TextCell Text="{Binding Attributes[comments]}" />
                    </DataTemplate>
                </ListView.ItemTemplate>
            </ListView>
        </Grid>
        <esriUI:MapView x:Name="MyMapView" Grid.Row="1" />
    </Grid>
</ContentPage>