Identify layers

Identify features in all layers in a map.

Use case

IdentifyLayers allows users to tap on a map, returning features at that location across multiple layers. Because some layer types have sublayers, the sample recursively counts results for sublayers within each layer.

How to use the sample

Tap to identify features. An alert will show all layers with features under the cursor, as well as a layer count.

How it works

1. The tapped position is passed to MapView.IdentifyLayersAsync
2. For each IdentifyLayerResult in the results, features are counted.
   • Note: there is one identify result per layer with matching features; if the feature count is 0, that means a sublayer contains the matching features.

Relevant API

• IdentifyLayerResult
• IdentifyLayerResult.LayerContent.Name
• IdentifyLayerResult.SublayerResults
• MapView.IdentifyLayersAsync

Additional information

The GeoView supports two methods of identify: IdentifyLayerAsync(), which identifies features within a specific layer and IdentifyLayersAsync(), which identifies features for all layers in the current view.

Tags

identify, recursion, recursive, sublayers

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<ContentPage x:Class="ArcGISRuntimeXamarin.Samples.IdentifyLayers.IdentifyLayers"
             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">
    <StackLayout Orientation="Vertical">
        <Label FontAttributes="Bold"
               HorizontalTextAlignment="Center"
               Text="Tap to identify features in all layers."
               VerticalOptions="Start" />
        <esriUI:MapView x:Name="MyMapView" VerticalOptions="FillAndExpand" />
    </StackLayout>
</ContentPage>