Data Layer: Drag and Drop GeoJSON

To use this example, drag and drop a GeoJSON file or files from your computer on to the map above. You can also drag text or HTML GeoJSON content from another website or from the sample below.

View this example fullscreen or check out the reference documentation for google.maps.Data.

/* Map functions */

var map;

function initMap() {
  // set up the map
  map = new google.maps.Map(document.getElementById('map'), {
    center: new google.maps.LatLng(0, 0),
    zoom: 2
  });
}

function loadGeoJsonString(geoString) {
  var geojson = JSON.parse(geoString);
  map.data.addGeoJson(geojson);
  zoom(map);
}

/**
 * Update a map's viewport to fit each geometry in a dataset
 * @param {google.maps.Map} map The map to adjust
 */
function zoom(map) {
  var bounds = new google.maps.LatLngBounds();
  map.data.forEach(function(feature) {
    processPoints(feature.getGeometry(), bounds.extend, bounds);
  });
  map.fitBounds(bounds);
}

/**
 * Process each point in a Geometry, regardless of how deep the points may lie.
 * @param {google.maps.Data.Geometry} geometry The structure to process
 * @param {function(google.maps.LatLng)} callback A function to call on each
 *     LatLng point encountered (e.g. Array.push)
 * @param {Object} thisArg The value of 'this' as provided to 'callback' (e.g.
 *     myArray)
 */
function processPoints(geometry, callback, thisArg) {
  if (geometry instanceof google.maps.LatLng) {
    callback.call(thisArg, geometry);
  } else if (geometry instanceof google.maps.Data.Point) {
    callback.call(thisArg, geometry.get());
  } else {
    geometry.getArray().forEach(function(g) {
      processPoints(g, callback, thisArg);
    });
  }
}


/* DOM (drag/drop) functions */

function initEvents() {
  // set up the drag & drop events
  var mapContainer = document.getElementById('map');
  var dropContainer = document.getElementById('drop-container');

  // map-specific events
  mapContainer.addEventListener('dragenter', showPanel, false);

  // overlay specific events (since it only appears once drag starts)
  dropContainer.addEventListener('dragover', showPanel, false);
  dropContainer.addEventListener('drop', handleDrop, false);
  dropContainer.addEventListener('dragleave', hidePanel, false);
}

function showPanel(e) {
  e.stopPropagation();
  e.preventDefault();
  document.getElementById('drop-container').style.display = 'block';
  return false;
}

function hidePanel(e) {
  document.getElementById('drop-container').style.display = 'none';
}

function handleDrop(e) {
  e.preventDefault();
  e.stopPropagation();
  hidePanel(e);

  var files = e.dataTransfer.files;
  if (files.length) {
    // process file(s) being dropped
    // grab the file data from each file
    for (var i = 0, file; file = files[i]; i++) {
      var reader = new FileReader();
      reader.onload = function(e) {
        loadGeoJsonString(e.target.result);
      };
      reader.onerror = function(e) {
        console.error('reading failed');
      };
      reader.readAsText(file);
    }
  } else {
    // process non-file (e.g. text or html) content being dropped
    // grab the plain text version of the data
    var plainText = e.dataTransfer.getData('text/plain');
    if (plainText) {
      loadGeoJsonString(plainText);
    }
  }

  // prevent drag event from bubbling further
  return false;
}


function initialize() {
  initMap();
  initEvents();
}

<div id="map"></div>
<div id="drop-container"><div id="drop-silhouette"></div></div>

/* Always set the map height explicitly to define the size of the div
 * element that contains the map. */
#map {
  height: 100%;
}
/* Optional: Makes the sample page fill the window. */
html, body {
  height: 100%;
  margin: 0;
  padding: 0;
}

#floating-panel {
  position: absolute;
  top: 10px;
  left: 25%;
  z-index: 5;
  background-color: #fff;
  padding: 5px;
  border: 1px solid #999;
  text-align: center;
  font-family: 'Roboto','sans-serif';
  line-height: 30px;
  padding-left: 10px;
}

html { height: 100% }
body { height: 100%; margin: 0; padding: 0; overflow: hidden; }
#map { height: 100% }
#drop-container {
  display: none;
  height: 100%;
  width: 100%;
  position: absolute;
  z-index: 1;
  top: 0px;
  left: 0px;
  padding: 20px;
  background-color: rgba(100, 100, 100, 0.5);
}
#drop-silhouette {
  color: white;
  border: white dashed 8px;
  height: calc(100% - 56px);
  width: calc(100% - 56px);
  background-image: url('data:image/png;base64,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');
  background-repeat: no-repeat;
  background-position: center;
}

<!-- Replace the value of the key parameter with your own API key. -->
<script async defer
src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk&callback=initialize">
</script>

Try it yourself

Hover at top right of the code block to copy the code or open it in JSFiddle.

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="initial-scale=1.0" />
    <title>Data Layer: Drag and Drop GeoJSON</title>
    <style>
      html { height: 100% }
      body { height: 100%; margin: 0; padding: 0; overflow: hidden; }
      #map { height: 100% }
      #drop-container {
        display: none;
        height: 100%;
        width: 100%;
        position: absolute;
        z-index: 1;
        top: 0px;
        left: 0px;
        padding: 20px;
        background-color: rgba(100, 100, 100, 0.5);
      }
      #drop-silhouette {
        color: white;
        border: white dashed 8px;
        height: calc(100% - 56px);
        width: calc(100% - 56px);
        background-image: url('data:image/png;base64,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');
        background-repeat: no-repeat;
        background-position: center;
      }
    </style>
  </head>
  <body>
    <div id="map"></div>
    <div id="drop-container"><div id="drop-silhouette"></div></div>
    <script>
      /* Map functions */

      var map;

      function initMap() {
        // set up the map
        map = new google.maps.Map(document.getElementById('map'), {
          center: new google.maps.LatLng(0, 0),
          zoom: 2
        });
      }

      function loadGeoJsonString(geoString) {
        var geojson = JSON.parse(geoString);
        map.data.addGeoJson(geojson);
        zoom(map);
      }

      /**
       * Update a map's viewport to fit each geometry in a dataset
       * @param {google.maps.Map} map The map to adjust
       */
      function zoom(map) {
        var bounds = new google.maps.LatLngBounds();
        map.data.forEach(function(feature) {
          processPoints(feature.getGeometry(), bounds.extend, bounds);
        });
        map.fitBounds(bounds);
      }

      /**
       * Process each point in a Geometry, regardless of how deep the points may lie.
       * @param {google.maps.Data.Geometry} geometry The structure to process
       * @param {function(google.maps.LatLng)} callback A function to call on each
       *     LatLng point encountered (e.g. Array.push)
       * @param {Object} thisArg The value of 'this' as provided to 'callback' (e.g.
       *     myArray)
       */
      function processPoints(geometry, callback, thisArg) {
        if (geometry instanceof google.maps.LatLng) {
          callback.call(thisArg, geometry);
        } else if (geometry instanceof google.maps.Data.Point) {
          callback.call(thisArg, geometry.get());
        } else {
          geometry.getArray().forEach(function(g) {
            processPoints(g, callback, thisArg);
          });
        }
      }


      /* DOM (drag/drop) functions */

      function initEvents() {
        // set up the drag & drop events
        var mapContainer = document.getElementById('map');
        var dropContainer = document.getElementById('drop-container');

        // map-specific events
        mapContainer.addEventListener('dragenter', showPanel, false);

        // overlay specific events (since it only appears once drag starts)
        dropContainer.addEventListener('dragover', showPanel, false);
        dropContainer.addEventListener('drop', handleDrop, false);
        dropContainer.addEventListener('dragleave', hidePanel, false);
      }

      function showPanel(e) {
        e.stopPropagation();
        e.preventDefault();
        document.getElementById('drop-container').style.display = 'block';
        return false;
      }

      function hidePanel(e) {
        document.getElementById('drop-container').style.display = 'none';
      }

      function handleDrop(e) {
        e.preventDefault();
        e.stopPropagation();
        hidePanel(e);

        var files = e.dataTransfer.files;
        if (files.length) {
          // process file(s) being dropped
          // grab the file data from each file
          for (var i = 0, file; file = files[i]; i++) {
            var reader = new FileReader();
            reader.onload = function(e) {
              loadGeoJsonString(e.target.result);
            };
            reader.onerror = function(e) {
              console.error('reading failed');
            };
            reader.readAsText(file);
          }
        } else {
          // process non-file (e.g. text or html) content being dropped
          // grab the plain text version of the data
          var plainText = e.dataTransfer.getData('text/plain');
          if (plainText) {
            loadGeoJsonString(plainText);
          }
        }

        // prevent drag event from bubbling further
        return false;
      }


      function initialize() {
        initMap();
        initEvents();
      }
    </script>
    <script async defer
        src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initialize"></script>
  </body>
</html>

Try it yourself

Sample GeoJSON

傳送您對下列選項的寶貴意見...