Display KML network links

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Display a file with a KML network link, including displaying any network link control messages at launch.

screenshot

Use case

KML files can reference other KML files on the network and support automatically refreshing content. For example, survey workers will benefit from KML data shown on their devices automatically refreshing to show the most up-to-date state. Additionally, discovering KML files linked to the data they are currently viewing provides additional information to make better decisions in the field.

How to use the sample

The sample will load the KML file automatically. The data shown should refresh automatically every few seconds. Pan and zoom to explore the map.

The message button will show the last message received from the KML network resource.

How it works

  1. Create a KmlDataset from a KML source which has network links.
  2. Construct a KmlLayer with the dataset and add the layer as an operational layer.
  3. To listen for network messages by connecting to the signal, KmlDataset::kmlNetworkLinkMessageReceived.

Relevant API

  • KmlDataset(Url)
  • KmlLayer(KmlDataset)
  • KmlNetworkLink
  • kmlNetworkLinkMessageReceived

Offline data

This sample uses the radar.kmz file, which can be found on ArcGIS Online.

About the data

This map shows the current air traffic in parts of Europe with heading, altitude, and ground speed. Additionally, noise levels from ground monitoring stations are shown.

Tags

Keyhole, KML, KMZ, Network Link, Network Link Control, OGC

Sample Code

DisplayKmlNetworkLinks.qmlDisplayKmlNetworkLinks.cppDisplayKmlNetworkLinks.hMessageButton.qml
                                                                    
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// [WriteFile Name=DisplayKmlNetworkLinks, Category=Layers]
// [Legal]
// Copyright 2018 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.
// [Legal]

import QtQuick 2.6
import QtQuick.Controls 2.2
import QtQuick.Window 2.3
import Esri.Samples 1.0

DisplayKmlNetworkLinksSample {
    id: rootRectangle
    clip: true
    width: 800
    height: 600



    Dialog {
        id: messageDialog
        modal: true
        x: Math.round(parent.width - width) / 2
        y: Math.round(parent.height - height) / 2
        width: parent.width * 0.75
        standardButtons: Dialog.Ok
        title: "KML layer message"
        property alias text : textLabel.text
        Text {
            width: parent.width
            id: textLabel
            text: currentKmlNetworkMessage
            wrapMode: Text.WordWrap
        }
        onAccepted: {
            currentKmlNetworkMessage = ""; // Clear the message
        }
        onRejected: onAccepted()
    }

    SceneView {
        id: sceneView
        objectName: "sceneView"
        anchors.fill: parent

        MessageButton {
            visible: currentKmlNetworkMessage.length > 0
            anchors {
                bottom: sceneView.attributionTop
                horizontalCenter: parent.horizontalCenter
                margins: 10
            }
            onClicked: {
                messageDialog.open();
            }
        }
    }
}

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