Skip to content

Overview - For-hoops and Geo-J-cieON

Adding functionality to our MapLibreGL

Goals

  • Create a GeoJSON online and it to the map with JavaScript
  • Understand how JavaScript works with HTML and CSS
  • Understand how JavaScript variables, functions, methods work together

Lab Outline

  1. Creating a GeojSON
  2. Fetch and then statements
  3. For-Loops

Starting Template Code for lab #3

Use the following template code or your lab assignment #2:

index.html
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
<!DOCTYPE html>
<html>
    <head>
        <title>Hello World with MapLibreGl</title>
        <!-- hint: remember to change your page title! -->
        <meta charset="utf-8" />
        <link rel="shortcut icon" href="#">
        <link rel="stylesheet" href="styles/style.css">

        <!-- MapLibreGL's css-->
        <link rel="stylesheet" href="https://unpkg.com/maplibre-gl/dist/maplibre-gl.css" />

        <!-- MapLibreGL's JavaScript-->
        <script src="https://unpkg.com/maplibre-gl/dist/maplibre-gl.js"></script>
    </head>

    <body>
        <header>
            Hello World
            <!-- hint: you can make a menu with other links here if you'd like -->
        </header>

        <main>
            <div class="portfolio">
                <div id="contents"></div>
                <!-- Portfolio content goes here -->
                 <h2>Where I work</h2>
                 <ul>
                     <li>Los Angeles Metro</li>
                     <li>UCLA</li>
                     <li>Yindee Games</li>
                 </ul>
            </div>
            <div id="map"></div>
        </main>
        <div id="footer">
            Copyright(2024)
        </div>
        <script src="js/init.js"></script>
    </body>
</html>
styles/style.css
1
js/init.js
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
// Initialize the map
const map = new maplibregl.Map({
    container: 'map',
    style: 'https://api.maptiler.com/maps/streets-v2-light/style.json?key=wsyYBQjqRwKnNsZrtci1',
    center: [-118.4430,34.0691],
    zoom: 15
});

function addMarker(lat,lng,title,message){
    let popup_message = `<h2>${title}</h2> <h3>${message}</h3>`
    new maplibregl.Marker()
        .setLngLat([lng, lat])
        .setPopup(new maplibregl.Popup()
            .setHTML(popup_message))
        .addTo(map)
    createButtons(lat,lng,title);
    return message
}

function createButtons(lat,lng,title){
    const newButton = document.createElement("button"); 
    newButton.id = "button"+title; 
    newButton.innerHTML = title; 
    newButton.setAttribute("lat",lat); 
    newButton.setAttribute("lng",lng); 
    newButton.addEventListener('click', function(){
        map.flyTo({
            center: [lng,lat],
        })
    })
    document.getElementById("contents").appendChild(newButton);
}