Add dynamic entity layer

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Display data from an ArcGIS stream service using a dynamic entity layer.

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Use case

A stream service is a type of service provided by ArcGIS Velocity and GeoEvent Server that allows clients to receive a stream of data observations via a web socket. ArcGIS Maps SDK for Kotlin allows you to connect to a stream service and manage the information as dynamic entities and display them in a dynamic entity layer. Displaying information from feeds such as a stream service is important in applications like dashboards where users need to visualize and track updates of real-world objects in real-time.

Use ArcGISStreamService to manage the connection to the stream service and purge options to manage how much data is stored and maintained by the application. The dynamic entity layer will display the latest received observation, and you can set track display properties to determine how to display historical information for each dynamic entity. This includes the number of previous observations to show, whether to display track lines in-between previous observations, and setting renderers.

How to use the sample

Use the controls to connect to or disconnect from the stream service, modify display properties in the dynamic entity layer, and purge all observations from the application.

How it works

  1. Create an ArcGIStreamService using a Url.
  2. Set a DynamicEntityFilter on the stream service to limit the amount of data coming from the server.
  3. Set the MaximumDuration property of the stream service PurgeOptions to limit the amount of data managed by the application.
  4. Create a DynamicEntityLayer using the stream service.
  5. Update values in the layer's TrackDisplayProperties to customize the layer's appearance.
  6. Add the DynamicEntityLayer to the map.

Relevant API

  • ArcGISStreamService
  • DynamicEntity
  • DynamicEntityFilter
  • DynamicEntityLayer
  • DynamicEntityPurgeOptions
  • TrackDisplayProperties

About the data

This sample uses a stream service that simulates live data coming from snowplows near Sandy, Utah. There are multiple vehicle types and multiple agencies operating the snowplows.

Additional information

More information about dynamic entities can be found in the guide documentation.

Tags

data, dynamic, entity, live, purge, real-time, service, stream, track

Sample Code

MainActivity.ktMainActivity.ktBottomSheetContent.ktComposeMapView.ktMapViewModel.ktMainScreen.kt
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/* Copyright 2023 Esri
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package com.esri.arcgismaps.sample.adddynamicentitylayer

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.runtime.Composable
import com.arcgismaps.ApiKey
import com.arcgismaps.ArcGISEnvironment
import com.esri.arcgismaps.sample.sampleslib.theme.SampleAppTheme
import com.esri.arcgismaps.sample.adddynamicentitylayer.screens.MainScreen

class MainActivity : ComponentActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        // authentication with an API key or named user is
        // required to access basemaps and other location services
        ArcGISEnvironment.apiKey = ApiKey.create(BuildConfig.API_KEY)
        setContent {
            SampleAppTheme {
                AddDynamicEntityLayerApp()
            }
        }
    }

    @Composable
    private fun AddDynamicEntityLayerApp() {
        Surface(
            color = MaterialTheme.colorScheme.background
        ) {
            MainScreen(
                sampleName = getString(R.string.app_name),
                application = application
            )
        }
    }
}

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