You're all set!

To start developing, please head over to our developer documentation.

Activate the Google Maps JavaScript API

To get you started we'll guide you through the Google Developers Console to do a few things first:

  1. Create or choose a project
  2. Activate the Google Maps JavaScript API and related services
  3. Create appropriate keys
Continue

Customizing a Google Map: Custom Legends

Overview

Learn how to create a legend on a Google map through this tutorial. Legends generally describe the symbols and markers on a map. You can create them using the positioning feature of custom controls.

This tutorial uses the map below as an example.

Try it yourself

Below is the entire code you need to create the map and legend in this tutorial.

var map;
function initialize() {
  map = new google.maps.Map(document.getElementById('map'), {
    zoom: 16,
    center: new google.maps.LatLng(-33.91722, 151.23064),
    mapTypeId: 'roadmap',
    styles: [
      {
        featureType: 'road',
        elementType: 'geometry',
        stylers: [
          { color: '#000000' },
          { weight: 1.6 }
        ]
      }, {
        featureType: 'road',
        elementType: 'labels',
        stylers: [
          { saturation: -100 },
          { invert_lightness: true }
        ]
      }, {
        featureType: 'landscape',
        elementType: 'geometry',
        stylers: [
          { hue: '#ffff00' },
          { gamma: 1.4 },
          { saturation: 82 },
          { lightness: 96 }
        ]
      }, {
        featureType: 'poi.school',
        elementType: 'geometry',
        stylers: [
          { hue: '#fff700' },
          { lightness: -15 },
          { saturation: 99 }
        ]
      }, {
        featureType: 'poi',
        elementType: 'geometry',
        stylers: [
          { visibility: 'off' }
        ]
      }, {
        featureType: 'poi.school',
        elementType: 'geometry',
        stylers: [
          { visibility: 'on' },
          { hue: '#fff700' },
          { lightness: -15 },
          { saturation: 99 }
        ]
      }
    ]
  });

  var iconBase = 'https://maps.google.com/mapfiles/kml/shapes/';
  var icons = {
    parking: {
      name: 'Parking',
      icon: iconBase + 'parking_lot_maps.png'
    },
    library: {
      name: 'Library',
      icon: iconBase + 'library_maps.png'
    },
    info: {
      name: 'Info',
      icon: iconBase + 'info-i_maps.png'
    }
  };

  function addMarker(feature) {
    var marker = new google.maps.Marker({
      position: feature.position,
      icon: icons[feature.type].icon,
      map: map
    });
  }

  var features = [
    {
      position: new google.maps.LatLng(-33.91721, 151.22630),
      type: 'info'
    }, {
      position: new google.maps.LatLng(-33.91539, 151.22820),
      type: 'info'
    }, {
      position: new google.maps.LatLng(-33.91747, 151.22912),
      type: 'info'
    }, {
      position: new google.maps.LatLng(-33.91910, 151.22907),
      type: 'info'
    }, {
      position: new google.maps.LatLng(-33.91725, 151.23011),
      type: 'info'
    }, {
      position: new google.maps.LatLng(-33.91872, 151.23089),
      type: 'info'
    }, {
      position: new google.maps.LatLng(-33.91784, 151.23094),
      type: 'info'
    }, {
      position: new google.maps.LatLng(-33.91682, 151.23149),
      type: 'info'
    }, {
      position: new google.maps.LatLng(-33.91790, 151.23463),
      type: 'info'
    }, {
      position: new google.maps.LatLng(-33.91666, 151.23468),
      type: 'info'
    }, {
      position: new google.maps.LatLng(-33.916988, 151.233640),
      type: 'info'
    }, {
      position: new google.maps.LatLng(-33.91662347903106, 151.22879464019775),
      type: 'parking'
    }, {
      position: new google.maps.LatLng(-33.916365282092855, 151.22937399734496),
      type: 'parking'
    }, {
      position: new google.maps.LatLng(-33.91665018901448, 151.2282474695587),
      type: 'parking'
    }, {
      position: new google.maps.LatLng(-33.919543720969806, 151.23112279762267),
      type: 'parking'
    }, {
      position: new google.maps.LatLng(-33.91608037421864, 151.23288232673644),
      type: 'parking'
    }, {
      position: new google.maps.LatLng(-33.91851096391805, 151.2344058214569),
      type: 'parking'
    }, {
      position: new google.maps.LatLng(-33.91818154739766, 151.2346203981781),
      type: 'parking'
    }, {
      position: new google.maps.LatLng(-33.91727341958453, 151.23348314155578),
      type: 'library'
    }
  ];

  for (var i = 0, feature; feature = features[i]; i++) {
    addMarker(feature);
  }

  var legend = document.getElementById('legend');
  for (var key in icons) {
    var type = icons[key];
    var name = type.name;
    var icon = type.icon;
    var div = document.createElement('div');
    div.innerHTML = '<img src="' + icon + '"> ' + name;
    legend.appendChild(div);
  }

  map.controls[google.maps.ControlPosition.RIGHT_BOTTOM].push(legend);
}
<div id="map"></div>
<div id="legend"><h3>Legend</h3></div>
html, body {
        margin: 0;
        padding: 0;
        height: 100%;
        width: 100%;
      }
      #map {
        height: 400px;
        width: 100%;
      }
      #legend {
        font-family: Arial, sans-serif;
        background: #fff;
        padding: 10px;
        margin: 10px;
        border: 3px solid #000;
      }
      #legend h3 {
        margin-top: 0;
      }
      #legend img {
        vertical-align: middle;
      }
<!-- Replace the value of the key parameter with your own API key. -->
<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk&callback=initialize" async defer></script>
<!DOCTYPE html>
<html>
  <head>
    <title>Custom Legend</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
    <meta charset="utf-8">
    <style>
      html, body {
        margin: 0;
        padding: 0;
        height: 100%;
        width: 100%;
      }
      #map {
        height: 400px;
        width: 100%;
      }
      #legend {
        font-family: Arial, sans-serif;
        background: #fff;
        padding: 10px;
        margin: 10px;
        border: 3px solid #000;
      }
      #legend h3 {
        margin-top: 0;
      }
      #legend img {
        vertical-align: middle;
      }
    </style>
  </head>
  <body>
    <div id="map"></div>
    <div id="legend"><h3>Legend</h3></div>
    <script>
      var map;
      function initialize() {
        map = new google.maps.Map(document.getElementById('map'), {
          zoom: 16,
          center: new google.maps.LatLng(-33.91722, 151.23064),
          mapTypeId: 'roadmap',
          styles: [
            {
              featureType: 'road',
              elementType: 'geometry',
              stylers: [
                { color: '#000000' },
                { weight: 1.6 }
              ]
            }, {
              featureType: 'road',
              elementType: 'labels',
              stylers: [
                { saturation: -100 },
                { invert_lightness: true }
              ]
            }, {
              featureType: 'landscape',
              elementType: 'geometry',
              stylers: [
                { hue: '#ffff00' },
                { gamma: 1.4 },
                { saturation: 82 },
                { lightness: 96 }
              ]
            }, {
              featureType: 'poi.school',
              elementType: 'geometry',
              stylers: [
                { hue: '#fff700' },
                { lightness: -15 },
                { saturation: 99 }
              ]
            }, {
              featureType: 'poi',
              elementType: 'geometry',
              stylers: [
                { visibility: 'off' }
              ]
            }, {
              featureType: 'poi.school',
              elementType: 'geometry',
              stylers: [
                { visibility: 'on' },
                { hue: '#fff700' },
                { lightness: -15 },
                { saturation: 99 }
              ]
            }
          ]
        });

        var iconBase = 'https://maps.google.com/mapfiles/kml/shapes/';
        var icons = {
          parking: {
            name: 'Parking',
            icon: iconBase + 'parking_lot_maps.png'
          },
          library: {
            name: 'Library',
            icon: iconBase + 'library_maps.png'
          },
          info: {
            name: 'Info',
            icon: iconBase + 'info-i_maps.png'
          }
        };

        function addMarker(feature) {
          var marker = new google.maps.Marker({
            position: feature.position,
            icon: icons[feature.type].icon,
            map: map
          });
        }

        var features = [
          {
            position: new google.maps.LatLng(-33.91721, 151.22630),
            type: 'info'
          }, {
            position: new google.maps.LatLng(-33.91539, 151.22820),
            type: 'info'
          }, {
            position: new google.maps.LatLng(-33.91747, 151.22912),
            type: 'info'
          }, {
            position: new google.maps.LatLng(-33.91910, 151.22907),
            type: 'info'
          }, {
            position: new google.maps.LatLng(-33.91725, 151.23011),
            type: 'info'
          }, {
            position: new google.maps.LatLng(-33.91872, 151.23089),
            type: 'info'
          }, {
            position: new google.maps.LatLng(-33.91784, 151.23094),
            type: 'info'
          }, {
            position: new google.maps.LatLng(-33.91682, 151.23149),
            type: 'info'
          }, {
            position: new google.maps.LatLng(-33.91790, 151.23463),
            type: 'info'
          }, {
            position: new google.maps.LatLng(-33.91666, 151.23468),
            type: 'info'
          }, {
            position: new google.maps.LatLng(-33.916988, 151.233640),
            type: 'info'
          }, {
            position: new google.maps.LatLng(-33.91662347903106, 151.22879464019775),
            type: 'parking'
          }, {
            position: new google.maps.LatLng(-33.916365282092855, 151.22937399734496),
            type: 'parking'
          }, {
            position: new google.maps.LatLng(-33.91665018901448, 151.2282474695587),
            type: 'parking'
          }, {
            position: new google.maps.LatLng(-33.919543720969806, 151.23112279762267),
            type: 'parking'
          }, {
            position: new google.maps.LatLng(-33.91608037421864, 151.23288232673644),
            type: 'parking'
          }, {
            position: new google.maps.LatLng(-33.91851096391805, 151.2344058214569),
            type: 'parking'
          }, {
            position: new google.maps.LatLng(-33.91818154739766, 151.2346203981781),
            type: 'parking'
          }, {
            position: new google.maps.LatLng(-33.91727341958453, 151.23348314155578),
            type: 'library'
          }
        ];

        for (var i = 0, feature; feature = features[i]; i++) {
          addMarker(feature);
        }

        var legend = document.getElementById('legend');
        for (var key in icons) {
          var type = icons[key];
          var name = type.name;
          var icon = type.icon;
          var div = document.createElement('div');
          div.innerHTML = '<img src="' + icon + '"> ' + name;
          legend.appendChild(div);
        }

        map.controls[google.maps.ControlPosition.RIGHT_BOTTOM].push(legend);
      }
    </script>
    <script src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initialize"
    async defer></script>
  </body>
</html>

Handy tips: At the top right corner of every sample code section are two buttons.

  • Click the right-most button to copy the code.
  • Click the left-most button to open the sample in JSFiddle.

The sections below explain the main steps to create a legend.

Creating the legend container

The table below explains the code that customizes the legend.

Code and description
<div id="legend"><h3>Legend</h3></div>

Creates a div to hold the content.
Adds a heading level three (3) to the div.
map.controls[google.maps.ControlPosition.RIGHT_BOTTOM].push
(document.getElementById('legend'));

Positions the div at the right-bottom of the map by adding a control position.
Read about more control position options.
<style>
  #legend {
    background: white;
    padding: 10px;
  }
</style>

Styles the control using CSS.

Adding the legend content

Use the existing marker styles definition to populate the legend.

var legend = document.getElementById('legend');
for (var style in styles) {
  var name = style.name;
  var icon = style.icon;
  var div = document.createElement('div');
  div.innerHTML = '<img src="' + icon + '"> ' + name;
  legend.appendChild(div);
}

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