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瞭解如何透過本教學課程在 Google 地圖上建立圖例。圖例一般用來說明地圖上的符號和標記。您可以使用自訂控制項的定位功能建立圖例。
下方地圖包含圖例,提供地圖上三種不同自訂標記的相關資訊。
下方是您在本教學課程中建立地圖和圖例時所需的完整程式碼。
TypeScript
let map: google.maps.Map; function initMap(): void { map = new google.maps.Map(document.getElementById("map") as HTMLElement, { zoom: 16, center: new google.maps.LatLng(-33.91722, 151.23064), mapTypeId: "roadmap", }); const iconBase = "https://maps.google.com/mapfiles/kml/shapes/"; const icons: Record<string, any> = { parking: { name: "Parking", icon: iconBase + "parking_lot_maps.png", }, library: { name: "Library", icon: iconBase + "library_maps.png", }, info: { name: "Info", icon: iconBase + "info-i_maps.png", }, }; const features = [ { position: new google.maps.LatLng(-33.91721, 151.2263), type: "info", }, { position: new google.maps.LatLng(-33.91539, 151.2282), type: "info", }, { position: new google.maps.LatLng(-33.91747, 151.22912), type: "info", }, { position: new google.maps.LatLng(-33.9191, 151.22907), type: "info", }, { position: new google.maps.LatLng(-33.91725, 151.23011), type: "info", }, { position: new google.maps.LatLng(-33.91872, 151.23089), type: "info", }, { position: new google.maps.LatLng(-33.91784, 151.23094), type: "info", }, { position: new google.maps.LatLng(-33.91682, 151.23149), type: "info", }, { position: new google.maps.LatLng(-33.9179, 151.23463), type: "info", }, { position: new google.maps.LatLng(-33.91666, 151.23468), type: "info", }, { position: new google.maps.LatLng(-33.916988, 151.23364), type: "info", }, { position: new google.maps.LatLng(-33.91662347903106, 151.22879464019775), type: "parking", }, { position: new google.maps.LatLng(-33.916365282092855, 151.22937399734496), type: "parking", }, { position: new google.maps.LatLng(-33.91665018901448, 151.2282474695587), type: "parking", }, { position: new google.maps.LatLng(-33.919543720969806, 151.23112279762267), type: "parking", }, { position: new google.maps.LatLng(-33.91608037421864, 151.23288232673644), type: "parking", }, { position: new google.maps.LatLng(-33.91851096391805, 151.2344058214569), type: "parking", }, { position: new google.maps.LatLng(-33.91818154739766, 151.2346203981781), type: "parking", }, { position: new google.maps.LatLng(-33.91727341958453, 151.23348314155578), type: "library", }, ]; features.forEach((feature) => { new google.maps.Marker({ position: feature.position, icon: icons[feature.type].icon, map: map, }); }); const legend = document.getElementById("legend") as HTMLElement; for (const key in icons) { const type = icons[key]; const name = type.name; const icon = type.icon; const div = document.createElement("div"); div.innerHTML = '<img src="' + icon + '"> ' + name; legend.appendChild(div); } map.controls[google.maps.ControlPosition.RIGHT_BOTTOM].push(legend); } declare global { interface Window { initMap: () => void; } } window.initMap = initMap;
JavaScript
let map; function initMap() { map = new google.maps.Map(document.getElementById("map"), { zoom: 16, center: new google.maps.LatLng(-33.91722, 151.23064), mapTypeId: "roadmap", }); const iconBase = "https://maps.google.com/mapfiles/kml/shapes/"; const icons = { parking: { name: "Parking", icon: iconBase + "parking_lot_maps.png", }, library: { name: "Library", icon: iconBase + "library_maps.png", }, info: { name: "Info", icon: iconBase + "info-i_maps.png", }, }; const features = [ { position: new google.maps.LatLng(-33.91721, 151.2263), type: "info", }, { position: new google.maps.LatLng(-33.91539, 151.2282), type: "info", }, { position: new google.maps.LatLng(-33.91747, 151.22912), type: "info", }, { position: new google.maps.LatLng(-33.9191, 151.22907), type: "info", }, { position: new google.maps.LatLng(-33.91725, 151.23011), type: "info", }, { position: new google.maps.LatLng(-33.91872, 151.23089), type: "info", }, { position: new google.maps.LatLng(-33.91784, 151.23094), type: "info", }, { position: new google.maps.LatLng(-33.91682, 151.23149), type: "info", }, { position: new google.maps.LatLng(-33.9179, 151.23463), type: "info", }, { position: new google.maps.LatLng(-33.91666, 151.23468), type: "info", }, { position: new google.maps.LatLng(-33.916988, 151.23364), type: "info", }, { position: new google.maps.LatLng(-33.91662347903106, 151.22879464019775), type: "parking", }, { position: new google.maps.LatLng(-33.916365282092855, 151.22937399734496), type: "parking", }, { position: new google.maps.LatLng(-33.91665018901448, 151.2282474695587), type: "parking", }, { position: new google.maps.LatLng(-33.919543720969806, 151.23112279762267), type: "parking", }, { position: new google.maps.LatLng(-33.91608037421864, 151.23288232673644), type: "parking", }, { position: new google.maps.LatLng(-33.91851096391805, 151.2344058214569), type: "parking", }, { position: new google.maps.LatLng(-33.91818154739766, 151.2346203981781), type: "parking", }, { position: new google.maps.LatLng(-33.91727341958453, 151.23348314155578), type: "library", }, ]; features.forEach((feature) => { new google.maps.Marker({ position: feature.position, icon: icons[feature.type].icon, map: map, }); }); const legend = document.getElementById("legend"); for (const key in icons) { const type = icons[key]; const name = type.name; const icon = type.icon; const div = document.createElement("div"); div.innerHTML = '<img src="' + icon + '"> ' + name; legend.appendChild(div); } map.controls[google.maps.ControlPosition.RIGHT_BOTTOM].push(legend); } window.initMap = initMap;
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; } #legend { font-family: Arial, sans-serif; background: #fff; padding: 10px; margin: 10px; border: 3px solid #000; } #legend h3 { margin-top: 0; } #legend img { vertical-align: middle; }
HTML
<html> <head> <title>Custom Legend</title> <link rel="stylesheet" type="text/css" href="./style.css" /> <script type="module" src="./index.js"></script> </head> <body> <div id="map"></div> <div id="legend"><h3>Legend</h3></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>
測試範例
以下各節說明建立圖例的主要步驟。
建立圖例容器
下表說明自訂圖例的程式碼。
程式碼與說明 | |
---|---|
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建立 div 來存放內容。在 div 中加入第三 (3) 層標題。 |
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新增控制項位置,將 div 放置在地圖右下角。請參閱更多控制項位置選項。 |
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使用 CSS 設定圖例控制項的樣式。 |
新增圖例內容
使用現有的標記樣式定義來填入圖例。
var legend = document.getElementById('legend');
for (var style in styles) {
var name = style.name;
var icon = style.icon;
var div = document.createElement('div');
div.innerHTML = '<img src="' + icon + '"> ' + name;
legend.appendChild(div);
}