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Inset Overview Map

  • This sample demonstrates how to create an inset map, providing a smaller overview map synchronized with a main map for better user orientation.

  • The overview map automatically adjusts its center and zoom level based on the main map's changes, using a predefined zoom difference and limits.

  • The sample includes code in TypeScript, JavaScript, CSS, and HTML, showcasing the implementation of the inset map functionality.

  • The overview map is positioned and styled using CSS to appear as an inset element within the main map container.

  • Users can interact with the main map, while the overview map passively reflects those changes, offering a broader geographical context.

Maintaining a geographical frame of reference

An inset map is a smaller map to help the user maintain a geographical frame ofreference. The overview map is synchronized with thebounds_changed event onthe main map.

TypeScript

constOVERVIEW_DIFFERENCE=5;constOVERVIEW_MIN_ZOOM=3;constOVERVIEW_MAX_ZOOM=10;functioninitMap():void{constmapOptions={center:{lat:50,lng:8},zoom:7,};// instantiate the primary mapmap=newgoogle.maps.Map(document.getElementById("map")asHTMLElement,{...mapOptions,});// instantiate the overview map without controlsoverview=newgoogle.maps.Map(document.getElementById("overview")asHTMLElement,{...mapOptions,disableDefaultUI:true,gestureHandling:"none",zoomControl:false,});functionclamp(num,min,max){returnMath.min(Math.max(num,min),max);}map.addListener("bounds_changed",()=>{overview.setCenter(map.getCenter()!);overview.setZoom(clamp(map.getZoom()!-OVERVIEW_DIFFERENCE,OVERVIEW_MIN_ZOOM,OVERVIEW_MAX_ZOOM));});}declareglobal{interfaceWindow{initMap:()=>void;}}window.initMap=initMap;
Note: Read theguide on using TypeScript and Google Maps.

JavaScript

constOVERVIEW_DIFFERENCE=5;constOVERVIEW_MIN_ZOOM=3;constOVERVIEW_MAX_ZOOM=10;functioninitMap(){constmapOptions={center:{lat:50,lng:8},zoom:7,};// instantiate the primary mapmap=newgoogle.maps.Map(document.getElementById("map"),{...mapOptions,});// instantiate the overview map without controlsoverview=newgoogle.maps.Map(document.getElementById("overview"),{...mapOptions,disableDefaultUI:true,gestureHandling:"none",zoomControl:false,});functionclamp(num,min,max){returnMath.min(Math.max(num,min),max);}map.addListener("bounds_changed",()=>{overview.setCenter(map.getCenter());overview.setZoom(clamp(map.getZoom()-OVERVIEW_DIFFERENCE,OVERVIEW_MIN_ZOOM,OVERVIEW_MAX_ZOOM,),);});}window.initMap=initMap;
Note: The JavaScript is compiled from the TypeScript snippet.

CSS

/* * 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;}#container,#map{height:100%;width:100%;}#map{position:relative;}#overview{position:absolute;left:40px;height:175px;width:175px;bottom:50px;box-shadow:02px6pxrgba(0,0,0,0.3);}

HTML

<html>  <head>    <title>Inset Overview Map</title>    <link rel="stylesheet" type="text/css" href="./style.css" />    <script type="module" src="./index.js"></script>  </head>  <body>    <div>      <div></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=initMap&v=weekly"      defer    ></script>  </body></html>

Try Sample

Clone Sample

Git and Node.js are required to run this sample locally. Follow theseinstructions to install Node.js and NPM. The following commands clone, install dependencies and start the sample application.

gitclone-bsample-inset-maphttps://github.com/googlemaps/js-samples.gitcdjs-samplesnpminpmstart

Other samples can be tried by switching to any branch beginning withsample-SAMPLE_NAME.

gitcheckoutsample-SAMPLE_NAMEnpminpmstart

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Last updated 2025-11-21 UTC.