我希望在每个国家/地区名称附近添加一个小标签，以显示其人口(例如巴西 [200,0000] )。有没有办法使用 Google map JS api 来做到这一点？
我当前的 map 初始化代码:
// Define options
var options = {
center: {
lat: 48.1250223,
lng: 4.1264001
},
zoom: 3
};
// Init map
map = new google.maps.Map( $container.get(0), options );
如有任何帮助，我们将不胜感激!
最佳答案
Google Maps API v3 中不提供人口数据。 您将需要从外部源导入数据。
您可以从 Google API https://developers.google.com/maps/documentation/javascript/combining-data 查看此示例
完整代码
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
<title>Mashups with google.maps.Data</title>
<style>
html, body, #map { height: 100%; margin: 0; padding: 0; overflow: hidden; }
.nicebox {
position: absolute;
text-align: center;
font-family: "Roboto", "Arial", sans-serif;
font-size: 13px;
z-index: 5;
box-shadow: 0 4px 6px -4px #333;
padding: 5px 10px;
background: rgb(255,255,255);
background: linear-gradient(to bottom,rgba(255,255,255,1) 0%,rgba(245,245,245,1) 100%);
border: rgb(229, 229, 229) 1px solid;
}
#controls {
top: 10px;
left: 110px;
width: 360px;
height: 45px;
}
#data-box {
top: 10px;
left: 500px;
height: 45px;
line-height: 45px;
display: none;
}
#census-variable {
width: 360px;
height: 20px;
}
#legend { display: flex; display: -webkit-box; padding-top: 7px }
.color-key {
background: linear-gradient(to right,
hsl(5, 69%, 54%) 0%,
hsl(29, 71%, 51%) 17%,
hsl(54, 74%, 47%) 33%,
hsl(78, 76%, 44%) 50%,
hsl(102, 78%, 41%) 67%,
hsl(127, 81%, 37%) 83%,
hsl(151, 83%, 34%) 100%);
flex: 1;
-webkit-box-flex: 1;
margin: 0 5px;
text-align: left;
font-size: 1.0em;
line-height: 1.0em;
}
#data-value { font-size: 2.0em; font-weight: bold }
#data-label { font-size: 2.0em; font-weight: normal; padding-right: 10px; }
#data-label:after { content: ':' }
#data-caret { margin-left: -5px; display: none; font-size: 14px; width: 14px}
</style>
</head>
<body>
<div id="controls" class="nicebox">
<div>
<select id="census-variable">
<option value="https://storage.googleapis.com/mapsdevsite/json/DP02_0066PE">Percent of population over 25 that completed high
school</option>
<option value="https://storage.googleapis.com/mapsdevsite/json/DP05_0017E">Median age</option>
<option value="https://storage.googleapis.com/mapsdevsite/json/DP05_0001E">Total population</option>
<option value="https://storage.googleapis.com/mapsdevsite/json/DP02_0016E">Average family size</option>
<option value="https://storage.googleapis.com/mapsdevsite/json/DP03_0088E">Per-capita income</option>
</select>
</div>
<div id="legend">
<div id="census-min">min</div>
<div class="color-key"><span id="data-caret">◆</span></div>
<div id="census-max">max</div>
</div>
</div>
<div id="data-box" class="nicebox">
<label id="data-label" for="data-value"></label>
<span id="data-value"></span>
</div>
<div id="map"></div>
<script>
var mapStyle = [{
'stylers': [{'visibility': 'off'}]
}, {
'featureType': 'landscape',
'elementType': 'geometry',
'stylers': [{'visibility': 'on'}, {'color': '#fcfcfc'}]
}, {
'featureType': 'water',
'elementType': 'geometry',
'stylers': [{'visibility': 'on'}, {'color': '#bfd4ff'}]
}];
var map;
var censusMin = Number.MAX_VALUE, censusMax = -Number.MAX_VALUE;
function initMap() {
// load the map
map = new google.maps.Map(document.getElementById('map'), {
center: {lat: 40, lng: -100},
zoom: 4,
styles: mapStyle
});
// set up the style rules and events for google.maps.Data
map.data.setStyle(styleFeature);
map.data.addListener('mouseover', mouseInToRegion);
map.data.addListener('mouseout', mouseOutOfRegion);
// wire up the button
var selectBox = document.getElementById('census-variable');
google.maps.event.addDomListener(selectBox, 'change', function() {
clearCensusData();
loadCensusData(selectBox.options[selectBox.selectedIndex].value);
});
// state polygons only need to be loaded once, do them now
loadMapShapes();
}
/** Loads the state boundary polygons from a GeoJSON source. */
function loadMapShapes() {
// load US state outline polygons from a GeoJson file
map.data.loadGeoJson('https://storage.googleapis.com/mapsdevsite/json/states.js', { idPropertyName: 'STATE' });
// wait for the request to complete by listening for the first feature to be
// added
google.maps.event.addListenerOnce(map.data, 'addfeature', function() {
google.maps.event.trigger(document.getElementById('census-variable'),
'change');
});
}
/**
* Loads the census data from a simulated API call to the US Census API.
*
* @param {string} variable
*/
function loadCensusData(variable) {
// load the requested variable from the census API (using local copies)
var xhr = new XMLHttpRequest();
xhr.open('GET', variable + '.json');
xhr.onload = function() {
var censusData = JSON.parse(xhr.responseText);
censusData.shift(); // the first row contains column names
censusData.forEach(function(row) {
var censusVariable = parseFloat(row[0]);
var stateId = row[1];
// keep track of min and max values
if (censusVariable < censusMin) {
censusMin = censusVariable;
}
if (censusVariable > censusMax) {
censusMax = censusVariable;
}
// update the existing row with the new data
map.data
.getFeatureById(stateId)
.setProperty('census_variable', censusVariable);
});
// update and display the legend
document.getElementById('census-min').textContent =
censusMin.toLocaleString();
document.getElementById('census-max').textContent =
censusMax.toLocaleString();
};
xhr.send();
}
/** Removes census data from each shape on the map and resets the UI. */
function clearCensusData() {
censusMin = Number.MAX_VALUE;
censusMax = -Number.MAX_VALUE;
map.data.forEach(function(row) {
row.setProperty('census_variable', undefined);
});
document.getElementById('data-box').style.display = 'none';
document.getElementById('data-caret').style.display = 'none';
}
/**
* Applies a gradient style based on the 'census_variable' column.
* This is the callback passed to data.setStyle() and is called for each row in
* the data set. Check out the docs for Data.StylingFunction.
*
* @param {google.maps.Data.Feature} feature
*/
function styleFeature(feature) {
var low = [5, 69, 54]; // color of smallest datum
var high = [151, 83, 34]; // color of largest datum
// delta represents where the value sits between the min and max
var delta = (feature.getProperty('census_variable') - censusMin) /
(censusMax - censusMin);
var color = [];
for (var i = 0; i < 3; i++) {
// calculate an integer color based on the delta
color[i] = (high[i] - low[i]) * delta + low[i];
}
// determine whether to show this shape or not
var showRow = true;
if (feature.getProperty('census_variable') == null ||
isNaN(feature.getProperty('census_variable'))) {
showRow = false;
}
var outlineWeight = 0.5, zIndex = 1;
if (feature.getProperty('state') === 'hover') {
outlineWeight = zIndex = 2;
}
return {
strokeWeight: outlineWeight,
strokeColor: '#fff',
zIndex: zIndex,
fillColor: 'hsl(' + color[0] + ',' + color[1] + '%,' + color[2] + '%)',
fillOpacity: 0.75,
visible: showRow
};
}
/**
* Responds to the mouse-in event on a map shape (state).
*
* @param {?google.maps.MouseEvent} e
*/
function mouseInToRegion(e) {
// set the hover state so the setStyle function can change the border
e.feature.setProperty('state', 'hover');
var percent = (e.feature.getProperty('census_variable') - censusMin) /
(censusMax - censusMin) * 100;
// update the label
document.getElementById('data-label').textContent =
e.feature.getProperty('NAME');
document.getElementById('data-value').textContent =
e.feature.getProperty('census_variable').toLocaleString();
document.getElementById('data-box').style.display = 'block';
document.getElementById('data-caret').style.display = 'block';
document.getElementById('data-caret').style.paddingLeft = percent + '%';
}
/**
* Responds to the mouse-out event on a map shape (state).
*
* @param {?google.maps.MouseEvent} e
*/
function mouseOutOfRegion(e) {
// reset the hover state, returning the border to normal
e.feature.setProperty('state', 'normal');
}
</script>
<script async defer
src="https://maps.googleapis.com/maps/api/js?callback=initMap">
</script>
</body>
</html>关于javascript - 如何向 Google map 中的国家/地区名称添加标签？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/47220407/