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I searched a lot on the web and I found similar question, but unfortunately no one has solved the problem, so I opened my own question hoping someone with a solution.

Essentially I want display a specific city, in this case Milan located in Italy. I successfully initialized the map:

var myMap;
var myLatlng = new google.maps.LatLng(45.4627123, 9.1075212,12);
function initialize() {
    var mapOptions = {
        zoom: 13,
        center: myLatlng,
        mapTypeId: google.maps.MapTypeId.ROADMAP,
        scrollwheel: false
    }
    myMap = new google.maps.Map(document.getElementById('worldMap'), mapOptions);
    var marker = new google.maps.Marker({
        position: myLatlng,
        map: myMap,
        title: Lang.geolocation,
        icon: 'http://www.google.com/intl/en_us/mapfiles/ms/micons/red-dot.png'
    });
}
google.maps.event.addDomListener(window, 'load', initialize);

this display the map:

enter image description here

but I want display only the city of Milan like:

enter image description here

how can I do this?

ps: the last image comes from the plugin jvectormap

sfarzoso
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  • Related question (replace "country" with "city"): [Country specific zoom level in Google Maps API](https://stackoverflow.com/questions/28126462/country-specific-zoom-level-in-google-maps-api) – geocodezip Feb 11 '19 at 20:14

1 Answers1

1

One option:

  1. go to http://www.gadm.org/download, download the adm3 file for Italy (you can use other sources of data, Natural Earth had similar information)

  2. Unzip that file, edit the contained KML to remove all the <Placemark>s that aren't Milan.

  3. Combine that polygon (as the inner ring(s)) with a polygon that covers the whole earth (more details in my answer to the question: KML invert country border)

  4. Display on the map using geoxml3 (example)

proof of concept fiddle

Code:

function initialize() {
  var map = new google.maps.Map(
  document.getElementById("map_canvas"), {
    center: new google.maps.LatLng(45.468889,9.202216),
    zoom: 11,
    mapTypeId: google.maps.MapTypeId.ROADMAP
  });
  var geoXml = new geoXML3.parser({
    map: map,
    suppressInfoWindows: true,
    zoom: false, 
  });
  geoXml.parse("http://www.geocodezip.com/geoxml3_test/kml/Milano_inverted.kml");
}
google.maps.event.addDomListener(window, "load", initialize);

Working example

screenshot of resulting map

code snippet:

var map;

function initialize() {
  map = new google.maps.Map(document.getElementById('map'), {
    center: new google.maps.LatLng(45.468889, 9.202216),
    zoom: 11,
    mapTypeId: google.maps.MapTypeId.ROADMAP
  });
  var geoXml = new geoXML3.parser({
    map: map,
    suppressInfoWindows: true,
    zoom: false,
  });
  // geoXml.parse("http://www.geocodezip.com/geoxml3_test/kml/Milano_inverted.kml");
  geoXml.parseKmlString(kmlStr);
}
google.maps.event.addDomListener(window, "load", initialize);
var kmlStr = '<?xml version="1.0" encoding="utf-8" ?><kml xmlns="http://www.opengis.net/kml/2.2"><Document id="root_doc"><Style id="1"><LineStyle><width>1.5</width><color>ff000000</color></LineStyle><PolyStyle><color>aa0000df</color><fill>1</fill></PolyStyle></Style><Folder><name>gadm36_ITA_3</name><Placemark><Style><LineStyle><width>1.5</width><color>ff000000</color></LineStyle><PolyStyle><color>ff000000</color><fill>1</fill></PolyStyle></Style><ExtendedData><SchemaData schemaUrl="#gadm36_ITA_3"><SimpleData name="NAME_0">Italy</SimpleData><SimpleData name="NAME_1">Lombardia</SimpleData><SimpleData name="NAME_2">Milano</SimpleData><SimpleData name="NAME_3">Milano</SimpleData> </SchemaData></ExtendedData><MultiGeometry><Polygon><outerBoundaryIs><LinearRing><coordinates>180,85 90,85 0,85 -90,85 -180,85 -180,0 -180,-85 -90,-85 0,-85 90,-85 180,-85 180,0 180,85</coordinates></LinearRing></outerBoundaryIs><innerBoundaryIs><LinearRing><coordinates>9.10490036010737,45.4479179382324 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html,
body,
#map {
  height: 100%;
  margin: 0;
  padding: 0;
}
<div id="map"></div>
<!-- Replace the value of the key parameter with your own API key. -->
<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk"></script>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/geocodezip/geoxml3@master/polys/geoxml3.js"></script>

To restrict it to be always displayed on the map see this page from Mike Williams' v2 tutorial

geocodezip
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  • Re: step 3, added link to related question. Compare the [original](http://www.geocodezip.com/geoxml3_test/kml/Milano.kml) and [inverted](http://www.geocodezip.com/geoxml3_test/kml/Milano_inverted.kml) KML files to see what I did.. – geocodezip Feb 14 '19 at 14:32
  • Note that it gets more complicated if you have multiple separate polygons that need to be holes in the "world covering" polygon. – geocodezip Feb 14 '19 at 14:42