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Legend in Vue Maps component

26 Nov 2021 / 14 minutes to read

A Legend is a visual representation of the symbols used on the Maps. It can be represented in various colors, shapes or other identifiers based on the data and provides valuable information for interpreting what the Maps are displaying. It explains what each symbol in the Maps represents. Legends are enabled by setting the visible property of legendSettings to true.

Modes of legend

Legend had two types of mode.

  1. Default mode
  2. Interactive mode

Default mode

Default mode legends having symbols with legend labels, used to identify the shape or bubble or marker color. To enable this option by setting the mode property of legendSettings as Default.

Interactive mode

The legends can be made interactive with an arrow mark indicating the exact range color in the legend when the mouse hovers over the corresponding shapes. To enable this type of mode by setting the mode property of legendSettings as Interactive. The invertedPointer property is used to enable or disable the visibility of the inverted pointer in interactive legend in Maps.

Source
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app.vue
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<template>
<div id="app">
      <div class='wrapper'>
        <ejs-maps :legendSettings='legendSettings' >
            <e-layers>
                <e-layer :shapeData='shapeData' :shapePropertyPath='shapePropertyPath' :shapeDataPath='shapeDataPath' :dataSource='dataSource' :shapeSettings='shapeSettings' ></e-layer>
            </e-layers>
        </ejs-maps>
    </div>
</div>
</template>

<script>
import Vue from 'vue';
import { MapsPlugin, Legend } from '@syncfusion/ej2-vue-maps';
import { world_map } from './world-map.js';
Vue.use(MapsPlugin);
export default {
data () {
return {
    legendSettings: {
        visible: true,
        mode: 'Interactive',
        invertedPointer: true
    },
    shapeData: world_map,
    dataSource: [
        { "Country": "China", "Membership": "Permanent" },
        { "Country": "France", "Membership": "Permanent" },
        { "Country": "Russia", "Membership": "Permanent" },
        { "Country": "Kazakhstan", "Membership": "Non-Permanent" },
        { "Country": "Poland", "Membership": "Non-Permanent" },
        { "Country": "Sweden", "Membership": "Non-Permanent" }
    ],
    shapePropertyPath: 'name',
    shapeDataPath: 'Country',
    shapeSettings: {
        colorValuePath: 'Membership',
        colorMapping: [
            {
                value: 'Permanent', color: '#D84444'
            },
            {
                value: 'Non-Permanent', color: '#316DB5'
            }
        ]
    }
}
},
provide: {
maps: [Legend]
}
}
</script>
<style>
  .wrapper {
max-width: 400px;
margin: 0 auto;
  }
</style>

Positioning of the legend

The legend can be positioned in the following two ways:

  • Absolute position
  • Dock position

Absolute position

The legend of the Maps can be positioned using the location property in the legendSettings. For positioning the legend based on co-ordinates corresponding to a Maps, the position property is set as Float.

Dock position

Legends are positioned in the following locations within the container. The position property in legendSettings is used to set these options in Maps.

  • Top
  • Left
  • Bottom
  • Right

The above four positions can be aligned with combination of Near, Center and Far using alignment property in legendSettings. So, the legend can be aligned to 12 positions.

Source
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app.vue
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<template>
<div id="app">
      <div class='wrapper'>
        <ejs-maps :legendSettings='legendSettings' >
            <e-layers>
                <e-layer :shapeData='shapeData' :shapePropertyPath='shapePropertyPath' :shapeDataPath='shapeDataPath' :dataSource='dataSource' :shapeSettings='shapeSettings' ></e-layer>
            </e-layers>
        </ejs-maps>
    </div>
</div>
</template>

<script>
import Vue from 'vue';
import { MapsPlugin, Legend } from '@syncfusion/ej2-vue-maps';
import { world_map } from './world-map.js';
Vue.use(MapsPlugin);
export default {
data () {
return {
    legendSettings: {
        visible: true,
        position: 'Top',
        alignment: 'Near'
    },
    shapeData: world_map,
    dataSource: [
        { "Country": "China", "Membership": "Permanent" },
        { "Country": "France", "Membership": "Permanent" },
        { "Country": "Russia", "Membership": "Permanent" },
        { "Country": "Kazakhstan", "Membership": "Non-Permanent" },
        { "Country": "Poland", "Membership": "Non-Permanent" },
        { "Country": "Sweden", "Membership": "Non-Permanent" }
    ],
    shapePropertyPath: 'name',
    shapeDataPath: 'Country',
    shapeSettings: {
        colorValuePath: 'Membership',
        colorMapping: [
            {
                value: 'Permanent', color: '#D84444'
            },
            {
                value: 'Non-Permanent', color: '#316DB5'
            }
        ]
    }
}
},
provide: {
maps: [Legend]
}
}
</script>
<style>
  .wrapper {
max-width: 400px;
margin: 0 auto;
  }
</style>

Legend for shapes

Legend for shapes can be generated from color mapping types such as equal color mapping, range color mapping and desaturation color mapping.

The below code snippet demonstrate the equal color mapping legends for the shapes. To bind the given data source to the dataSource property of layerSettings. Set the value of shapePropertyPath to name and shapeDataPath to Country. To enable equal color mapping, set the colorMapping as an array in shapeSettings. Finally, set the visible property of legendSettings as true. The label property in colorMapping is used to set the text name for legend in Maps.

Source
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app.vue
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<template>
<div id="app">
      <div class='wrapper'>
        <ejs-maps :legendSettings='legendSettings' >
            <e-layers>
                <e-layer :shapeData='shapeData' :shapePropertyPath='shapePropertyPath' :shapeDataPath='shapeDataPath' :dataSource='dataSource' :shapeSettings='shapeSettings'>
                </e-layer>
            </e-layers>
        </ejs-maps>
    </div>
</div>
</template>

<script>
import Vue from 'vue';
import { MapsPlugin, Legend } from '@syncfusion/ej2-vue-maps';
import { world_map } from './world-map.js';
Vue.use(MapsPlugin);
export default {
data () {
return {
    legendSettings: {
        visible: true
    },
    shapeData: world_map,
    dataSource: [
        {  "Country": "China", "Membership": "Permanent" },
        { "Country": "France","Membership": "Permanent" },
        { "Country": "Russia","Membership": "Permanent" },
        { "Country": "Kazakhstan","Membership": "Non-Permanent" },
        { "Country": "Poland","Membership": "Non-Permanent" },
        { "Country": "Sweden","Membership": "Non-Permanent" }
    ],
    shapePropertyPath: 'name',
    shapeDataPath: 'Country',
    shapeSettings: {
        colorValuePath: 'Membership',
        colorMapping: [
            { value: 'Permanent', color: '#D84444' },
            { value: 'Non-Permanent', color: '#316DB5' }
        ]
    }
}
},
provide: {
maps: [Legend]
}
}
</script>
<style>
  .wrapper {
max-width: 400px;
margin: 0 auto;
  }
</style>

Legend shape

Maps supports the following types of legend shapes. The shape property in the legendSettings can be used to change the type of legend shapes.

  • Circle
  • Rectangle
  • Triangle
  • Diamond
  • Cross
  • Star
  • HorizontalLine
  • VerticalLine
  • Pentagon
  • InvertedTriangle

The shape of legends can be customized by using the shapeWidth, shapeHeight, shapeBorder and shapePadding properties.

Customization

The following properties are available in legend to customize the legend shape and legend text in Maps.

  • background - To customize the background color of the Legend.
  • border - To customize the color, width and opacity of the border for the Legend.
  • fill - To apply the color for the Legend.
  • labelDisplayMode - To customize the display mode for the Legend text.
  • labelPosition - To customize the position of the Legend text.
  • orientation - To customize the orientation of the Legend.
  • textStyle - To customize the text style for Legend.
  • title - To apply the title for the Legend.
  • titleStyle - To customize the style of the title for the Legend.
  • height - To customize the height of the Legend.
  • width - To customize the width of the Legend.
  • opacity - To apply the opacity to the Legend.
Source
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app.vue
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<template>
<div id="app">
      <div class='wrapper'>
        <ejs-maps :legendSettings='legendSettings' >
            <e-layers>
                <e-layer :shapeData='shapeData' :shapePropertyPath='shapePropertyPath' :shapeDataPath='shapeDataPath' :dataSource='dataSource' :shapeSettings='shapeSettings' ></e-layer>
            </e-layers>
        </ejs-maps>
    </div>
</div>
</template>

<script>
import Vue from 'vue';
import { MapsPlugin, Legend } from '@syncfusion/ej2-vue-maps';
import { world_map } from './world-map.js';
Vue.use(MapsPlugin);
export default {
data () {
return {
    legendSettings: {
        visible: true,
        background: 'green',
        border: {
            color: 'blue',
            width: 2
        },
        fill: 'orange',
        labelPosition: 'Before',
        orientation: 'Vertical',
        textStyle: {
            size: '12px',
            color: 'red',
            fontStyle: 'italic'
        },
        title: {
            description: 'Legend title',
            text: 'Legend'
        },
        titleStyle: {
            size: '12px',
            color: '#d6e341',
            fontStyle: 'italic'
        }
    },
    shapeData: world_map,
    dataSource: [
        { "Country": "China", "Membership": "Permanent" },
        { "Country": "France", "Membership": "Permanent" },
        { "Country": "Russia", "Membership": "Permanent" },
        { "Country": "Kazakhstan", "Membership": "Non-Permanent" },
        { "Country": "Poland", "Membership": "Non-Permanent" },
        { "Country": "Sweden", "Membership": "Non-Permanent" }
    ],
    shapePropertyPath: 'name',
    shapeDataPath: 'Country',
    shapeSettings: {
        colorValuePath: 'Membership',
        colorMapping: [
            {
                value: 'Permanent', color: '#D84444'
            },
            {
                value: 'Non-Permanent', color: '#316DB5'
        }]
    }
}
},
provide: {
maps: [Legend]
}
}
</script>
<style>
  .wrapper {
max-width: 400px;
margin: 0 auto;
  }
</style>

Legend for items excluded from color mapping

The legend can be enabled for items excluded from the color mapping using the color property in colorMapping. Refer to the population_density data which demonstrates the population density of some countries.

Copied to clipboard
export let population_density = [
...
{
    'code': 'AE',
    'value': 90,
    'name': 'United Arab Emirates',
    'population': 8264070,
    'density': 99
},
{
    'code': 'GB',
    'value': 257,
    'name': 'United Kingdom',
    'population': 62041708,
    'density': 255
},
{
    'code': 'US',
    'value': 34,
    'name': 'United States',
    'population': 325020000,
    'density': 33
}
...
];

In the following example, color mapping is added for the ranges from 0 to 200. If there are any records in the data source that are outside of this range, the color mapping will not be applied. To apply the color for these excluded items, set the color property alone in the colorMapping. To enable legend for these items, set the visible property of legendSettings to true.

Source
Preview
app.vue
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<template>
<div id="app">
    <div class='wrapper'>
        <ejs-maps :legendSettings='legendSettings'>
            <e-layers>
                <e-layer :shapeData='shapeData' :shapePropertyPath='shapePropertyPath' :shapeDataPath='shapeDataPath' :dataSource='dataSource' :shapeSettings='shapeSettings' ></e-layer>
            </e-layers>
        </ejs-maps>
    </div>
</div>
</template>

<script>
import Vue from 'vue';
import { MapsPlugin, Legend } from '@syncfusion/ej2-vue-maps';
import { world_map } from './world-map.js';
import { population_density } from './population-density.js';
Vue.use(MapsPlugin);
export default {
data () {
return {
    shapeData: world_map,
    legendSettings: {
        visible: true
    },
    shapeDataPath: 'name',
    shapePropertyPath: 'name',
    dataSource: population_density,
    shapeSettings: {
        colorValuePath: 'density',
        colorMapping: [
            {
                from: 0, to: 100, color: ['red','blue']
            },
            {
                from: 101, to: 200, color: ['green','yellow']
            },
            {
                color: 'green'
            }
        ]
    }
}
},
provide: {
maps: [Legend]
}
}
</script>
<style>
  .wrapper {
max-width: 400px;
margin: 0 auto;
  }
</style>

Hide desired legend items

Use the showLegend property in the colorMapping to show or hide the desired legend items in Maps. If the showLegend property is set to false, the legend item will be hidden. otherwise, it will be visible.

Source
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app.vue
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<template>
<div id="app">
    <div class='wrapper'>
        <ejs-maps :legendSettings='legendSettings'>
            <e-layers>
                <e-layer :shapeData='shapeData' :shapePropertyPath='shapePropertyPath' :shapeDataPath='shapeDataPath' :dataSource='dataSource' :shapeSettings='shapeSettings' ></e-layer>
            </e-layers>
        </ejs-maps>
    </div>
</div>
</template>

<script>
import Vue from 'vue';
import { MapsPlugin, Legend } from '@syncfusion/ej2-vue-maps';
import { world_map } from './world-map.js';
import { population_density } from './population-density.js';
Vue.use(MapsPlugin);
export default {
data () {
return {
    shapeData: world_map,
    legendSettings: {
        visible: true
    },
    shapeDataPath: 'name',
    shapePropertyPath: 'name',
    dataSource: population_density,
    shapeSettings: {
        colorValuePath: 'density',
        colorMapping: [
            {
                from: 0, to: 100, color: 'rgb(153,174,214)', showLegend: true
            },
            {
                from: 101, to: 200, color: 'rgb(115,143,199)', showLegend: false
            },
            {
                color: 'rgb(77,112,184)', showLegend: false
            }
        ]
    }
}
},
provide: {
maps: [Legend]
}
}
</script>
<style>
  .wrapper {
max-width: 400px;
margin: 0 auto;
  }
</style>

Hide legend items based on data source value

Depending on the boolean values provided in the data source, the legend items will be hidden or visible. Bind the field name that contains the visibility state in the data source to the showLegendPath property of the legendSettings to achieve this.

Source
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app.vue
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<template>
<div id="app">
    <div class='wrapper'>
        <ejs-maps :legendSettings='legendSettings'>
            <e-layers>
                <e-layer :shapeData='shapeData' :shapePropertyPath='shapePropertyPath' :shapeDataPath='shapeDataPath' :dataSource='dataSource' :shapeSettings='shapeSettings' ></e-layer>
            </e-layers>
        </ejs-maps>
    </div>
</div>
</template>

<script>
import Vue from 'vue';
import { MapsPlugin, Legend } from '@syncfusion/ej2-vue-maps';
import { World_Map } from './worldmap.js';
import { default_data } from './legenddata.js';
Vue.use(MapsPlugin);
export default {
data () {
return {
    shapeData: World_Map,
    legendSettings: {
        visible: true,
        showLegendPath:'visibility'
    },
    shapeDataPath: 'continent',
    shapePropertyPath: 'continent',
    dataSource: default_data,
    shapeSettings: {
        colorValuePath: 'color',
    }
}
},
provide: {
maps: [Legend]
}
}
</script>
<style>
  .wrapper {
max-width: 400px;
margin: 0 auto;
  }
</style>

Binding legend item text from data source

To show the legend text based on values provided in the data source, use the valuePath property in the legendSettings.

Source
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app.vue
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<template>
<div id="app">
    <div class='wrapper'>
        <ejs-maps :legendSettings='legendSettings'>
            <e-layers>
                <e-layer :shapeData='shapeData' :shapePropertyPath='shapePropertyPath' :shapeDataPath='shapeDataPath' :dataSource='dataSource' :shapeSettings='shapeSettings' ></e-layer>
            </e-layers>
        </ejs-maps>
    </div>
</div>
</template>

<script>
import Vue from 'vue';
import { MapsPlugin, Legend } from '@syncfusion/ej2-vue-maps';
import { World_Map } from './worldmap.js';
import { default_data } from './legenddata.js';
Vue.use(MapsPlugin);
export default {
data () {
return {
    shapeData: World_Map,
    legendSettings: {
        visible: true,
        valuePath:'continent'
    },
    shapeDataPath: 'continent',
    shapePropertyPath: 'continent',
    dataSource: default_data,
    shapeSettings: {
        colorValuePath: 'color',
    }
}
},
provide: {
maps: [Legend]
}
}
</script>
<style>
  .wrapper {
max-width: 400px;
margin: 0 auto;
  }
</style>

Hide duplicate legend items

To hide the duplicate legend items in Maps, set the removeDuplicateLegend property to true in the legendSettings.

Source
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app.vue
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<template>
<div id="app">
    <div class='wrapper'>
        <ejs-maps :legendSettings='legendSettings'>
            <e-layers>
                <e-layer :shapeData='shapeData' :shapePropertyPath='shapePropertyPath' :shapeDataPath='shapeDataPath' :dataSource='dataSource' :shapeSettings='shapeSettings' ></e-layer>
            </e-layers>
        </ejs-maps>
    </div>
</div>
</template>

<script>
import Vue from 'vue';
import { MapsPlugin, Legend } from '@syncfusion/ej2-vue-maps';
import { World_Map } from './worldmap.js';
import { default_data } from './legenddata.js';
Vue.use(MapsPlugin);
export default {
data () {
return {
    shapeData: World_Map,
    legendSettings: {
        visible: true,
        valuePath: 'continent',
        removeDuplicateLegend: true
    },
    shapeDataPath: 'continent',
    shapePropertyPath: 'continent',
    dataSource: default_data,
    shapeSettings: {
        colorValuePath: 'color',
    }
}
},
provide: {
maps: [Legend]
}
}
</script>
<style>
  .wrapper {
max-width: 400px;
margin: 0 auto;
  }
</style>

Toggle option in legend

The toggle option has been provided for legend. If the legend can be toggled, the given color will be changed to the corresponding Maps shape item. To enable the toggle options in Legend, set the enable property of the toggleLegendSettings to true.

The following properties are available to customize the toggle option in legend.

  • applyShapeSettings – To apply the fill property value to the shape of the Maps when toggling the legend items.
  • fill - To apply the color to the shape of the Maps for which legend item is toggled.
  • opacity – To customize the transparency for the shapes for which legend item is toggled.
  • border – To customize the color, width and opacity of the border of the shapes in Maps.
Source
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app.vue
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<template>
<div id="app">
    <div class='wrapper'>
        <ejs-maps :legendSettings='legendSettings'>
            <e-layers>
                <e-layer :shapeData='shapeData' :shapePropertyPath='shapePropertyPath' :shapeDataPath='shapeDataPath' :dataSource='dataSource' :shapeSettings='shapeSettings' ></e-layer>
            </e-layers>
        </ejs-maps>
    </div>
</div>
</template>

<script>
import Vue from 'vue';
import { MapsPlugin, Legend } from '@syncfusion/ej2-vue-maps';
import { World_Map } from './worldmap.js';
import { Population_Density } from './populationdensity.js';
Vue.use(MapsPlugin);
export default {
data () {
return {
    shapeData: World_Map,
    legendSettings: {
        visible: true,
        toggleLegendSettings: {
            enable: true,
            applyShapeSettings: false,
            border: {
                color: "green",
                width: 2
            }
        }
    },
    shapeDataPath: 'name',
    shapePropertyPath: 'name',
    dataSource: Population_Density,
    shapeSettings: {
        colorValuePath: 'density',
         colorMapping: [
            {
                from: 0, to: 100, color: 'rgb(153,174,214)',
            },
            {
                from: 101, to: 200, color: 'rgb(115,143,199)',
            },
            {
                color: 'rgb(77,112,184)'
            },
        ]
    }
}
},
provide: {
maps: [Legend]
}
}
</script>
<style>
  .wrapper {
max-width: 400px;
margin: 0 auto;
  }
</style>

Enable legend for bubbles

To enable the legend for the bubble by setting the visible property of legendSettings as true and type property of legendSettings as Bubbles.

Source
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app.vue
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<template>
<div id="app">
    <div class='wrapper'>
        <ejs-maps :legendSettings='legendSettings' >
            <e-layers>
                <e-layer :shapeData='shapeData' :shapePropertyPath='shapePropertyPath' :shapeDataPath='shapeDataPath' :bubbleSettings='bubbleSettings' ></e-layer>
            </e-layers>
        </ejs-maps>
    </div>
</div>
</template>

<script>
import Vue from 'vue';
import { MapsPlugin, Bubble, Legend } from '@syncfusion/ej2-vue-maps';
import { world_map } from './world-map.js';
Vue.use(MapsPlugin);
export default {
data () {
return {
    legendSettings: {
        visible: true,
        type: 'Bubbles'
    },
    shapeData: world_map,
    shapeDataPath: 'name',
    shapePropertyPath: 'name',
    bubbleSettings: [{
        visible: true,
        minRadius: 20,
        dataSource: [
            { color: 'green', name: 'India', population: '38332521' },
            { color: 'purple', name: 'New Zealand', population: '19651127' },
            { color: 'blue', name: 'Pakistan', population: '3090416' }
        ],
        maxRadius: 40,
        colorValuePath: 'color',
        valuePath: 'population'
    }]
}
},
provide: {
maps: [Bubble, Legend]
}
}
</script>
<style>
  .wrapper {
max-width: 400px;
margin: 0 auto;
  }
</style>

Enable legend for markers

To enable legend for marker by setting the visible property of legendSettings as true and type property of legendSettings as Markers. The legendText property in the markerSettings can be used to show the legend text based on values provided in the data source.

Source
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app.vue
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<template>
<div id="app">
    <div class='wrapper'>
        <ejs-maps :legendSettings='legendSettings' >
            <e-layers>
                <e-layer :shapeData='shapeData' :markerSettings='markerSettings' ></e-layer>
            </e-layers>
        </ejs-maps>
    </div>
</div>
</template>

<script>
import Vue from 'vue';
import { MapsPlugin, Marker, Legend } from '@syncfusion/ej2-vue-maps';
import { world_map } from './world-map.js';
Vue.use(MapsPlugin);
export default {
data () {
return {
    legendSettings: {
        visible: true,
        type: 'Markers'
    },
    shapeData: world_map,
    markerSettings: [
        {
            visible: true,
            legendText: 'name',
            dataSource: [
                { latitude: 37.6276571, longitude: -122.4276688, name: 'San Bruno' },
                { latitude: 33.5302186, longitude: -117.7418381, name: 'Laguna Niguel' },
                { latitude: 40.7424509, longitude: -74.0081468, name: 'New York' }
            ],
            shape: 'Circle'
        }
    ]
}
},
provide: {
maps: [Legend, Marker]
}
}
</script>
<style>
  .wrapper {
max-width: 400px;
margin: 0 auto;
  }
</style>