Esri Leaflet

Query without a map

It is not necessary to add a layer to a map in order to execute a spatial query. More information about Queries can be found in the L.esri.Query documentation.

computing...
<html>
<head>
  <meta charset=utf-8 />
  <title>Query without a map</title>
  <meta name='viewport' content='initial-scale=1,maximum-scale=1,user-scalable=no' />

  <!-- Load Leaflet from CDN-->
  <link rel="stylesheet" href="https://unpkg.com/leaflet@1.0.3/dist/leaflet.css" />
  <script src="https://unpkg.com/leaflet@1.0.3/dist/leaflet-src.js"></script>

  <!-- Load Esri Leaflet from CDN -->
  <script src="https://unpkg.com/esri-leaflet@2.0.7"></script>

  <style>
    body { margin:0; padding:0; }
    #map { position: absolute; top:0; bottom:0; right:0; left:0; }
  </style>
</head>
<body>

<style>
  #message { margin: 10px }
</style>

<div id="map">
  <div id="message">computing...</div>
</div>
<div id="invisibleMap"></div>

<script>
  // html5 geolocation requires a secure connection
  if (window.location.host == 'esri.github.io' && window.location.protocol != "https:") {
    window.location.protocol = "https";
  }

  document.getElementById('map').style.height = '100px';

  // its not necessary to instaniate a map in order to execute a spatial query,
 //  we do it here because it provides a convenient way to ask the user for their HTML5 location
  var map = L.map('invisibleMap');
  map.locate();

  map.on("locationfound", function(e) {
    // use location to find out which census block they are inside.
    L.esri.query({
      url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer/1"
    }).intersects(e.latlng).run(function(error, censusBlocks){
        // if we find a match dig into the feature attributes to retrive median age
        if (censusBlocks.features.length > 0) {
          document.getElementById('message').innerHTML =
            'the median age of the census block where you are currently located is <b>' + censusBlocks.features[0].properties.MED_AGE +
            '</b> years old';
        }
        // otherwise, fail gracefully
        else {
          document.getElementById('message').innerHTML =
            'either you arent currently in the United States or you prefer not to say.';
        }
      });
  });
</script>

</body>
</html>