Samples/GeoJSON/Drag and Drop/GeoJson Drag and Drop.html

﻿<!DOCTYPE html>
<html lang="en">
<head>
    <title>GeoJson Drag and Drop - Bing Maps Samples</title>

    <meta charset="utf-8" />
	<link rel="shortcut icon" href="/favicon.ico"/>
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no" />
    <meta name="description" content="This code examples shows how to enable drag and drop a local GeoJSON file onto a map." />
    <meta name="keywords" content="Microsoft maps, map, gis, API, SDK, Bing, Bing Maps" />
    <meta name="author" content="Microsoft Bing Maps" />
    <meta name="screenshot" content="bmv8-geojson-la.jpg" />
    
    <script>
    var map;

    function GetMap() {
        map = new Microsoft.Maps.Map('#myMap', {
            zoom: 1
        });

        //Load the GeoJSON module.
        Microsoft.Maps.loadModule('Microsoft.Maps.GeoJson', function () {

            //Setup the drag & drop listeners on the map.
            var dropZone = document.getElementById('myMap');
            dropZone.addEventListener('dragover', handleDragOver, false);
            dropZone.addEventListener('drop', handleFileSelect, false);
        });
    }

    function handleDragOver(evt) {
        //Stop the browser from performing its default behavior when a file is dragged and dropped.
        evt.stopPropagation();
        evt.preventDefault();

        evt.dataTransfer.dropEffect = 'copy';
    }

    function handleFileSelect(evt) {
        //Stop the browser from performing its default behavior when a file is dragged and dropped.
        evt.stopPropagation();
        evt.preventDefault();

        //Remove any existing data from the map.
        map.entities.clear();

        //The list of files that have been dragged and dropped onto the map.
        var files = evt.dataTransfer.files; 

        //Keep track of the bounding box of all the data from all files dropped into the map.
        var dataBounds = null;

        //Loop through and attempt to read each file. 
        for (var i = 0; i < files.length; i++) {
            var reader = new FileReader();

            reader.onload = function (e) {
                try {
                    var geoJsonText = e.target.result;

                    //Attempt to parse the file as GeoJSON and add the shapes to the map.
                    var shapes = Microsoft.Maps.GeoJson.read(geoJsonText);
                    map.entities.push(shapes);
                    
                    //Calculate the bounding box of the data in the single file. 
                    var bounds = Microsoft.Maps.LocationRect.fromShapes(shapes);

                    //If data is already loaded from another GeoJSON file, merge the bounding boxes together.
                    if (dataBounds) {
                        dataBounds = Microsoft.Maps.LocationRect.merge(dataBounds, bounds);
                    } else {
                        dataBounds = bounds;
                    }

                    //Update the map view to show the data.
                    map.setView({ bounds: dataBounds, padding: 50 });
                } catch (e) {
                    alert('Unable to read file as GeoJSON.');
                }
            };

            //Read the file as text.
            reader.readAsText(files[i]);
        }
    }
    </script>
    
</head>
<body>
    <div id="myMap" style="position:relative;width:100%;min-width:290px;height:600px;background-color:gray"></div>

    <fieldset style="width:800px;margin-top:10px;">
        <legend>GeoJson Drag and Drop Sample</legend>
        This sample shows how load add support for dragging and droping GeoJSON files on to the map and having them render.
    </fieldset>

    <script>
        // Dynamic load the Bing Maps Key and Script
        // Get your own Bing Maps key at https://www.microsoft.com/maps
        (async () => {
            let script = document.createElement("script");
            let bingKey = await fetch("https://samples.azuremaps.com/api/GetBingMapsKey").then(r => r.text()).then(key => { return key });
            script.setAttribute("src", `https://www.bing.com/api/maps/mapcontrol?callback=GetMap&key=${bingKey}`);
            document.body.appendChild(script);
        })();
    </script>
</body>
</html>