Custom dictionary style

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Use a custom dictionary created from a web style or style file (.stylx) to symbolize features using a variety of attribute values.

screenshot

Use case

When symbolizing geoelements in your map, you may need to convey several pieces of information with a single symbol. You could try to symbolize such data using a unique value renderer, but as the number of fields and values increases, that approach becomes impractical. With a dictionary renderer you can build each symbol on-the-fly, driven by one or more attribute values, and handle a nearly infinite number of unique combinations.

How to use the sample

Use the radio buttons to toggle between the dictionary symbols from the web style and style file. Pan and zoom around the map to see the symbology from the chosen dictionary symbol style. The web style and style file are slightly different to each other to give a visual indication of the switch between the two.

How it works

  1. Create a new FeatureLayer and append it to the Map's operational layers.
  2. Use DictionarySymbolStyle::createFromFile() to create a DictionarySymbolStyle from a .stylx file.
  3. Create a DictionarySymbolStyle with a PortalItem.
  4. Create a DictionaryRenderer for each DictionarySymbolStyle.

    • Remap any inconsistent fields between the FeatureLayer and the DictionaryRenderer as needed.
  5. Apply the desired DictionaryRenderer to the FeatureLayer.

Relevant API

  • DictionaryRenderer
  • DictionarySymbolStyle
  • Portal
  • PortalItem

About the data

The data used in this sample is from a feature layer showing a subset of restaurants in Redlands, CA hosted as a feature service with attributes for rating, style, health score, and open hours.

The feature layer is symbolized using a dictionary renderer that displays a single symbol for all of these variables. The renderer uses symbols from a custom restaurant dictionary style created from a stylx file and a web style, available as an items from ArcGIS Online, to show unique symbols based on several feature attributes. The symbols it contains were created using ArcGIS Pro. The logic used to apply the symbols comes from an Arcade script embedded in the stylx file (which is a SQLite database), along with a JSON string that defines expected attribute names and configuration properties.

Additional information

For information about creating your own custom dictionary style, see the open source dictionary renderer toolkit on GitHub.

Tags

ArcGIS Online, dictionary, renderer, style, stylx, unique value, visualization, web style

Sample Code

CustomDictionaryStyle.qmlCustomDictionaryStyle.cppCustomDictionaryStyle.h
                                                                         
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// [WriteFile Name=CustomDictionaryStyle, Category=DisplayInformation]
// [Legal]
// Copyright 2019 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 Esri.Samples 1.0

Item {

    // add a mapView component
    MapView {
        id: view
        anchors.fill: parent
    }

    // Declare the C++ instance which creates the scene etc. and supply the view
    CustomDictionaryStyleSample {
        id: model
        mapView: view
    }

    Rectangle {
        id: rectangle
        anchors {
            left: parent.left
            top: parent.top
            margins: 5
        }
        width: radioColumn.width
        height: radioColumn.height
        color: "white"
        border {
            color: "black"
            width: 1
        }
        opacity: 0.9

        Column {
            id: radioColumn
            padding: 5
            spacing: 5

            Text {
                text: "Custom Dictionary Symbol Style Source"
            }

            RadioButton {
                text: "Local .stylx file"
                checked: true
            }

            RadioButton {
                text: "Web style"
                onCheckedChanged: {
                    model.changeDictionarySymbolStyleSource();
                }
            }
        }
    }
}

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