使用 Google Apps 腳本和 Leaflet.js 建立互動式 XY 圖像圖
- WBOY原創
- 2024-09-08 22:35:08897瀏覽
Google 地圖有大量用於在地圖上繪製點的功能，但是如果您想在圖像上繪製點怎麼辦？這些 XY 影像繪圖通常用於樓層地圖、工作現場檢查，甚至是遊戲。
在本指南中，我將向您展示如何使用 Leaflet.js 和 Google Apps 腳本建立具有可拖曳點的互動式地圖。我們將涵蓋從設定地圖到整合 Google 試算表中的資料以及將其部署為網頁應用程式的所有內容。
本指南將涵蓋：
在 Google Apps 腳本 HTML 服務中設定 Leaflet.js
使用 Google 表格中的資料顯示標記
移動標記時更新表格行
從地圖建立新標記並儲存到表格
從網路應用程式中刪除標記
在 Google Apps 腳本 HTML 服務中設定 Leaflet.js
Leaflet.js 是最受歡迎的開源地圖庫之一。它重量輕，易於使用，並且有很好的文件。它們支援大量不同的地圖類型，包括“CRS.Simple”或坐標參考系統，它允許您提供背景圖像。
Google 試算表設定
先建立一個名為map_pin 的工作表，其架構如下：
| id | title | x | y |
|---|---|---|---|
| 1 | test1 | 10 | 30 |
| 2 | test2 | 50 | 80 |
Then open Apps Script from the Extensions menu.
Creating HTML File
First, we'll start with the basic example from the Leaflet docs, just to get the library working. You can see the full example in their quick start guide, here.
Add a new HTML File named Index, and set the content to:
<!DOCTYPE html>
<html>
<head>
<title>Quick Start - Leaflet</title>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="https://unpkg.com/leaflet@1.9.3/dist/leaflet.css" />
<style>
#map {
height: 400px;
}
</style>
</head>
<body>
<div id="map"></div>
<script src="https://unpkg.com/leaflet@1.9.3/dist/leaflet.js"></script>
<script>
var map = L.map('map').setView([40.73, -73.99], 13);
L.tileLayer('https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
maxZoom: 19,
attribution: '© OpenStreetMap'
}).addTo(map);
var marker = L.marker([40.73, -73.99]).addTo(map)
.bindPopup('Test Popup Message')
.openPopup();
</script>
</body>
</html>
Then update the Code.gs file with:
function doGet() {
const html = HtmlService.createHtmlOutputFromFile('Index')
.setTitle('Map with Draggable Points')
.setXFrameOptionsMode(HtmlService.XFrameOptionsMode.ALLOWALL);
return html;
}
Save, and then click Deploy, and publish as a web app. Then open the link for the new deployment and you should see Leaflet.js displaying a map on New York.
Ok, that's the regular map example using Leaflet. Now on to the CRS.Simple map type, which allows supplying a background image.
Update the HTML with this example from the Leaflet Tutorials.
<!DOCTYPE html>
<html>
<head>
<title>CRS Simple Example - Leaflet</title>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="https://unpkg.com/leaflet@1.9.3/dist/leaflet.css" />
<style>
#map {
height: 400px;
width: 600px;
}
body {
margin: 0;
padding: 0;
}
</style>
</head>
<body>
<div id="map"></div>
<script src="https://unpkg.com/leaflet@1.9.3/dist/leaflet.js"></script>
<script>
// Set up the map with a simple CRS (no geographic projection)
var map = L.map('map', {
crs: L.CRS.Simple,
minZoom: -1,
maxZoom: 4
});
// Define the dimensions of the image
var bounds = [[0, 0], [1000, 1000]];
var image = L.imageOverlay('https://leafletjs.com/examples/crs-simple/uqm_map_full.png', bounds).addTo(map);
// Set the initial view of the map to show the whole image
map.fitBounds(bounds);
// Optional: Add a marker or other elements to the map
var marker = L.marker([500, 500]).addTo(map)
.bindPopup('Center of the image')
.openPopup();
</script>
</body>
</html>
Here we are supplying an image of 1000 x 1000 pixels, then setting the center marker at 500, 500.
Click Save, then Deploy>Test Deployments, to see the new map type. You should now have a map with a background image and a marker plotted in the center.
Initializing a Map with Data from Google Sheets
Next, we'll use data from the sheet to populate a set of markers on the map.
First, add a function to the Code.gs file to get the marker locations:
function getPinData(){
const ss = SpreadsheetApp.getActiveSpreadsheet();
const sh = ss.getSheetByName('map_pin');
const data = sh.getDataRange().getValues();
const json = arrayToJSON(data);
//Logger.log(json);
return json
}
function arrayToJSON(data=getPinData()){
const headers = data[0];
const rows = data.slice(1);
let jsonData = [];
for(row of rows){
const obj = {};
headers.forEach((h,i)=>obj[h] = row[i]);
jsonData.push(obj)
}
//Logger.log(jsonData)
return jsonData
}
Here I'm returning the pins as JSON so they're easier to work with in the HTML in the next section.
Now add a function to the HTML to loop over this JSON and create the map pins after the map has loaded.
// Add map pins from sheet data
google.script.run.withSuccessHandler(addMarkers).getPinData();
function addMarkers(mapPinData) {
mapPinData.forEach(pin => {
const marker = L.marker([pin.x, pin.y], {
draggable: true
}).addTo(map);
marker.bindPopup(`<b>${pin.title}`).openPopup();
marker.on('dragend', function(e) {
const latLng = e.target.getLatLng();
console.log(`Marker ${pin.title} moved to: ${latLng.lat}, ${latLng.lng}`);
});
});
}
Save, and then open the test deployment. You should now have markers generated from your sheet data!
Each pin has a popup with the title from that row. The pins are draggable at this point, but we still need a function to save the new position.
Saving Marker Position When Dragged
To save the new position, we need two functions: one in the HTML to capture the event on the client side, and one to save the new position on the server side, in the Code.gs file.
Update the HTML with:
function addMarkers(mapPinData) {
mapPinData.forEach(pin => {
const { id, title, x, y } = pin;
const marker = L.marker([x, y], {
draggable: true
}).addTo(map);
marker.bindPopup(`<b>${title}</b>`).openPopup();
marker.on('dragend', function(e) {
const latLng = e.target.getLatLng();
console.log(`Marker ${title} moved to: ${latLng.lat}, ${latLng.lng}`);
saveMarkerPosition({ id, title, lat: latLng.lat, lng: latLng.lng });
});
});
}
function saveMarkerPosition({ id, title, lat, lng }) {
google.script.run.saveMarkerPosition({ id, title, lat, lng });
}
And then add a function to the Code.gs file to save the location:
function saveMarkerPosition({ id, lat, lng }) {
const ss = SpreadsheetApp.getActiveSpreadsheet();
const sh = ss.getSheetByName('map_pin');
const data = sh.getDataRange().getValues();
for (let i = 1; i < data.length; i++) {
if (data[i][0] === id) { // ID column (index 0)
sh.getRange(i + 1, 3).setValue(lat); // latitude column
sh.getRange(i + 1, 4).setValue(lng); // longitude column
break;
}
}
}
Save, and refresh the test deployment. You should now see the sheet update when a marker is dragged!
Adding New Points
We can now move the existing points, but what about adding new ones? Again, we'll need two functions, one in the HTML, and one in the Code.gs file.
First, add a function to the HTML to open a prompt when the user clicks an empty spot on the map, and pass the value to a server function.
// Function to add a new pin
map.on('click', function(e) {
const latLng = e.latlng;
const title = prompt('Enter a title for the new pin:');
if (title) {
google.script.run.withSuccessHandler(function(id) {
addNewMarker({ id, title, lat: latLng.lat, lng: latLng.lng });
}).addNewPin({ title, lat: latLng.lat, lng: latLng.lng });
}
});
function addNewMarker({ id, title, lat, lng }) {
const marker = L.marker([lat, lng], {
draggable: true
}).addTo(map);
marker.bindPopup(`<b>${title}</b>`).openPopup();
marker.on('dragend', function(e) {
const latLng = e.target.getLatLng();
saveMarkerPosition({ id, title, lat: latLng.lat, lng: latLng.lng });
});
}
Then add the function to the Code.gs to save the new row.
function addNewPin({ title, lat, lng }) {
const ss = SpreadsheetApp.getActiveSpreadsheet();
const sh = ss.getSheetByName('map_pin');
// Check if there are any rows present, if not initialize ID
const lastRow = sh.getLastRow();
let newId = 1;
if (lastRow > 0) {
const lastId = sh.getRange(lastRow, 1).getValue();
newId = lastId + 1;
}
sh.appendRow([newId, title, lat, lng]);
return newId;
}
Save once more and refresh the test deployment. Now when you click an empty spot, you can enter a title and save a new marker!
Deleting A Marker
Lastly, we should add a way to delete markers, giving us a full CRUD app in map view.
Update the add marker function to give the popup a delete button:
const popupContent = `<b>${title}</b><br><button onclick="deleteMarker(${id})">Delete Marker</button>`;
marker.bindPopup(popupContent).openPopup();
And then add a function for deleting from the client side:
// Function to delete a marker
function deleteMarker(id) {
const confirmed = confirm('Are you sure you want to delete this marker?');
if (confirmed) {
google.script.run.withSuccessHandler(() => {
// Refresh the markers after deletion
google.script.run.withSuccessHandler(addMarkers).getPinData();
}).deleteMarker(id);
}
}
Then add the matching function to the Code.gs file:
function deleteMarker(id) {
const ss = SpreadsheetApp.getActiveSpreadsheet();
const sh = ss.getSheetByName('map_pin');
const data = sh.getDataRange().getValues();
for (let i = 1; i < data.length; i++) {
if (data[i][0] === id) { // ID column (index 0)
sh.deleteRow(i + 1); // Delete the row
break;
}
}
}
What's Next?
There's a ton more you could do from here, like adding other data points to each marker, dynamic background images, or other click and drag interactions. You could even make a game! Got an idea for a use case? Drop a comment below!
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