This example allows you to drag and drop GeoJSON onto the map. Download a sample GeoJSON file to test dragging from the device.
For more information about how to work with the map data layer, see the google.maps.Data class .
TypeScript
let map : google.maps.Map ; function initMap () : void { // set up the map map = new google . maps . Map ( document . getElementById ( "map" ) as HTMLElement , { center : new google . maps . LatLng ( 0 , 0 ), zoom : 4 , }); } function loadGeoJsonString ( geoString : string ) { try { const geojson = JSON . parse ( geoString ) as any ; map . data . addGeoJson ( geojson ); } catch ( e ) { alert ( "Not a GeoJSON file!" ); } zoom ( map ); } /** * Update a map's viewport to fit each geometry in a dataset */ function zoom ( map : google.maps.Map ) { const bounds = new google . maps . LatLngBounds (); map . data . forEach (( feature ) = > { const geometry = feature . getGeometry (); if ( geometry ) { processPoints ( geometry , bounds . extend , bounds ); } }); map . fitBounds ( bounds ); } /** * Process each point in a Geometry, regardless of how deep the points may lie. */ function processPoints ( geometry : google.maps.LatLng | google . maps . Data . Geometry , callback : any , thisArg : google.maps.LatLngBounds ) { if ( geometry instanceof google . maps . LatLng ) { callback . call ( thisArg , geometry ); } else if ( geometry instanceof google . maps . Data . Point ) { callback . call ( thisArg , geometry . get ()); } else { // @ts-ignore geometry . getArray (). forEach (( g ) = > { processPoints ( g , callback , thisArg ); }); } } /* DOM (drag/drop) functions */ function initEvents () { [... document . getElementsByClassName ( "file" )]. forEach (( fileElement ) = > { fileElement . addEventListener ( "dragstart" , ( e : Event ) = > { // @ts-ignore e . dataTransfer . setData ( "text/plain" , JSON . stringify ( files [ Number (( e . target as HTMLElement ). dataset . value )]) ); console . log ( e ); }, false ); }); // set up the drag & drop events const mapContainer = document . getElementById ( "map" ) as HTMLElement ; mapContainer . addEventListener ( "dragenter" , addClassToDropTarget , false ); mapContainer . addEventListener ( "dragover" , addClassToDropTarget , false ); mapContainer . addEventListener ( "drop" , handleDrop , false ); mapContainer . addEventListener ( "dragleave" , removeClassFromDropTarget , false ); } function addClassToDropTarget ( e : Event ) { e . stopPropagation (); e . preventDefault (); document . getElementById ( "map" ) ! . classList . add ( "over" ); return false ; } function removeClassFromDropTarget ( e : Event ) { document . getElementById ( "map" ) ! . classList . remove ( "over" ); } function handleDrop ( e : DragEvent ) { e . preventDefault (); e . stopPropagation (); removeClassFromDropTarget ( e ); const files = ( e . dataTransfer as DataTransfer ). files ; if ( files . length ) { // process file(s) being dropped // grab the file data from each file for ( let i = 0 , file ; ( file = files [ i ]); i ++ ) { const reader = new FileReader (); reader . onload = function ( e ) { loadGeoJsonString ( reader . result as string ); }; 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 const plainText = ( e . dataTransfer as DataTransfer ). getData ( "text/plain" ); console . log ( plainText ); if ( plainText ) { loadGeoJsonString ( plainText ); } } // prevent drag event from bubbling further return false ; } function initialize () { initMap (); initEvents (); } const files = [ { type : "FeatureCollection" , features : [ { type : "Feature" , properties : {}, geometry : { type : "Polygon" , coordinates : [ [ [ - 99.49218749999999 , - 11.867350911459294 ], [ 24.960937499999996 , - 11.867350911459294 ], [ 24.960937499999996 , 47.517200697839414 ], [ - 99.49218749999999 , 47.517200697839414 ], [ - 99.49218749999999 , - 11.867350911459294 ], ], ], }, }, ], }, { type : "FeatureCollection" , features : [ { type : "Feature" , properties : {}, geometry : { type : "Point" , coordinates : [ 81.2109375 , 50.064191736659104 ], }, }, { type : "Feature" , properties : {}, geometry : { type : "Point" , coordinates : [ 103.35937499999999 , - 47.98992166741417 ], }, }, { type : "Feature" , properties : {}, geometry : { type : "Point" , coordinates : [ - 46.05468749999999 , 64.01449619484472 ], }, }, { type : "Feature" , properties : {}, geometry : { type : "Point" , coordinates : [ - 113.203125 , 37.996162679728116 ], }, }, { type : "Feature" , properties : {}, geometry : { type : "Point" , coordinates : [ - 73.828125 , - 32.249974455863295 ], }, }, ], }, { type : "FeatureCollection" , features : [ { type : "Feature" , properties : {}, geometry : { type : "LineString" , coordinates : [ [ 147.65625 , - 5.266007882805485 ], [ 118.47656249999999 , 43.83452678223682 ], [ 80.85937499999999 , - 30.145127183376115 ], [ 35.15625 , 51.83577752045248 ], [ - 15.468749999999998 , - 23.563987128451217 ], [ - 29.53125 , 44.33956524809713 ], [ - 73.47656249999999 , - 32.842673631954305 ], [ - 104.765625 , 35.460669951495305 ], ], }, }, ], }, ]; declare global { interface Window { initialize : () = > void ; } } window . initialize = initialize ;
JavaScript
let map ; function initMap () { // set up the map map = new google . maps . Map ( document . getElementById ( "map" ), { center : new google . maps . LatLng ( 0 , 0 ), zoom : 4 , }); } function loadGeoJsonString ( geoString ) { try { const geojson = JSON . parse ( geoString ); map . data . addGeoJson ( geojson ); } catch ( e ) { alert ( "Not a GeoJSON file!" ); } zoom ( map ); } /** * Update a map's viewport to fit each geometry in a dataset */ function zoom ( map ) { const bounds = new google . maps . LatLngBounds (); map . data . forEach (( feature ) = > { const geometry = feature . getGeometry (); if ( geometry ) { processPoints ( geometry , bounds . extend , bounds ); } }); map . fitBounds ( bounds ); } /** * Process each point in a Geometry, regardless of how deep the points may lie. */ 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 { // @ts-ignore geometry . getArray (). forEach (( g ) = > { processPoints ( g , callback , thisArg ); }); } } /* DOM (drag/drop) functions */ function initEvents () { [... document . getElementsByClassName ( "file" )]. forEach (( fileElement ) = > { fileElement . addEventListener ( "dragstart" , ( e ) = > { // @ts-ignore e . dataTransfer . setData ( "text/plain" , JSON . stringify ( files [ Number ( e . target . dataset . value )]), ); console . log ( e ); }, false , ); }); // set up the drag & drop events const mapContainer = document . getElementById ( "map" ); mapContainer . addEventListener ( "dragenter" , addClassToDropTarget , false ); mapContainer . addEventListener ( "dragover" , addClassToDropTarget , false ); mapContainer . addEventListener ( "drop" , handleDrop , false ); mapContainer . addEventListener ( "dragleave" , removeClassFromDropTarget , false ); } function addClassToDropTarget ( e ) { e . stopPropagation (); e . preventDefault (); document . getElementById ( "map" ). classList . add ( "over" ); return false ; } function removeClassFromDropTarget ( e ) { document . getElementById ( "map" ). classList . remove ( "over" ); } function handleDrop ( e ) { e . preventDefault (); e . stopPropagation (); removeClassFromDropTarget ( e ); const files = e . dataTransfer . files ; if ( files . length ) { // process file(s) being dropped // grab the file data from each file for ( let i = 0 , file ; ( file = files [ i ]); i ++ ) { const reader = new FileReader (); reader . onload = function ( e ) { loadGeoJsonString ( reader . 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 const plainText = e . dataTransfer . getData ( "text/plain" ); console . log ( plainText ); if ( plainText ) { loadGeoJsonString ( plainText ); } } // prevent drag event from bubbling further return false ; } function initialize () { initMap (); initEvents (); } const files = [ { type : "FeatureCollection" , features : [ { type : "Feature" , properties : {}, geometry : { type : "Polygon" , coordinates : [ [ [ - 99.49218749999999 , - 11.867350911459294 ], [ 24.960937499999996 , - 11.867350911459294 ], [ 24.960937499999996 , 47.517200697839414 ], [ - 99.49218749999999 , 47.517200697839414 ], [ - 99.49218749999999 , - 11.867350911459294 ], ], ], }, }, ], }, { type : "FeatureCollection" , features : [ { type : "Feature" , properties : {}, geometry : { type : "Point" , coordinates : [ 81.2109375 , 50.064191736659104 ], }, }, { type : "Feature" , properties : {}, geometry : { type : "Point" , coordinates : [ 103.35937499999999 , - 47.98992166741417 ], }, }, { type : "Feature" , properties : {}, geometry : { type : "Point" , coordinates : [ - 46.05468749999999 , 64.01449619484472 ], }, }, { type : "Feature" , properties : {}, geometry : { type : "Point" , coordinates : [ - 113.203125 , 37.996162679728116 ], }, }, { type : "Feature" , properties : {}, geometry : { type : "Point" , coordinates : [ - 73.828125 , - 32.249974455863295 ], }, }, ], }, { type : "FeatureCollection" , features : [ { type : "Feature" , properties : {}, geometry : { type : "LineString" , coordinates : [ [ 147.65625 , - 5.266007882805485 ], [ 118.47656249999999 , 43.83452678223682 ], [ 80.85937499999999 , - 30.145127183376115 ], [ 35.15625 , 51.83577752045248 ], [ - 15.468749999999998 , - 23.563987128451217 ], [ - 29.53125 , 44.33956524809713 ], [ - 73.47656249999999 , - 32.842673631954305 ], [ - 104.765625 , 35.460669951495305 ], ], }, }, ], }, ]; window . initialize = initialize ;
CSS
html { height : 100 % ; } body { height : 100 % ; margin : 0 ; padding : 0 ; overflow : hidden ; } # map { height : 100 % ; } # map . over { opacity : 0.5 ; background-color : rgba ( 100 , 100 , 100 , 0.5 ); } # sidebar { flex-direction : column ; align-items : center ; justify-content : center ; overflow : auto ; } . file { display : flex ; flex-flow : column ; margin-top : 1 em ; cursor : move ; text-align : center ; } . file : hover . material-icons { color : darkorange ; } . file : hover . filename { font-weight : bold ; } . file . material-icons { font-size : 50 px ; color : orange ; } . file . material-icons : hover { color : darkorange ; } . file . filename { margin-top : 0.5 em ; font-size : 20 px ; color : #333333 ; } /* Optional: Makes the sample page fill the window. */ html , body { height : 100 % ; margin : 0 ; padding : 0 ; } # container { height : 100 % ; display : flex ; } # sidebar { flex-basis : 15 rem ; flex-grow : 1 ; padding : 1 rem ; max-width : 30 rem ; height : 100 % ; box-sizing : border-box ; overflow : auto ; } # map { flex-basis : 0 ; flex-grow : 4 ; height : 100 % ; }
HTML
<html> <head> <title>Data Layer: Drag and Drop GeoJSON</title> <link href="https://unpkg.com/material-components-web@6.0.0/dist/material-components-web.css" rel="stylesheet" /> <link rel="stylesheet" href="https://fonts.googleapis.com/icon?family=Material+Icons" /> <link rel="stylesheet" type="text/css" href="./style.css" /> <script type="module" src="./index.js"></script> </head> <body> <div id="container"> <div id="map"></div> <div id="sidebar" class="mdc-typography"> <div class="file" draggable="true" data-value="0"> <span class="material-icons">text_snippet</span> <div class="filename">polygons.geojson</div> </div> <div class="file" draggable="true" data-value="1"> <span class="material-icons">text_snippet</span> <div class="filename">points.geojson</div> </div> <div class="file" draggable="true" data-value="2"> <span class="material-icons">text_snippet</span> <div class="filename">polyline.geojson</div> </div> </div> </div> <!-- The `defer` attribute causes the script to execute after the full HTML document has been parsed. For non-blocking uses, avoiding race conditions, and consistent behavior across browsers, consider loading using Promises. See https://developers.google.com/maps/documentation/javascript/load-maps-js-api for more information. --> <script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyB41DRUbKWJHPxaFjMAwdrzWzbVKartNGg&callback=initialize&v=weekly" defer ></script> </body> </html>
Try Sample
Clone Sample
Git and Node.js are required to run this sample locally. Follow these instructions to install Node.js and NPM. The following commands clone, install dependencies and start the sample application.
git clone - b sample - layer - data - dragndrop https : //github.com/googlemaps/js-samples.gitcd js - samplesnpm inpm start
Other samples can be tried by switching to any branch beginning with sample- SAMPLE_NAME
.
git checkout sample - SAMPLE_NAMEnpm inpm start
