原文链接及内容

运行界面

关于Blob(全称为:Binary large object)更多内容请参考MDN文档:https://developer.mozilla.org/zh-CN/docs/Web/API/Blob

将来自COG的切片数据渲染为图层,在本例中,将使用单个3波段的GeoTIFF渲染来自Blob对象的RGB数据。

main.js代码如下:

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import GeoTIFF from 'ol/source/GeoTIFF.js';
import Map from 'ol/Map.js';
import TileLayer from 'ol/layer/WebGLTile.js';

fetch('data/example.tif')
.then((response) => response.blob())
.then((blob) => {
const source = new GeoTIFF({
sources: [
{
blob: blob,
},
],
});

const map = new Map({
target: 'map',
layers: [
new TileLayer({
source: source,
}),
],
view: source.getView().then((viewConfig) => {
viewConfig.showFullExtent = true;
return viewConfig;
}),
});
});

界面布局文件index.html代码如下:

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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Cloud Optimized GeoTIFF (COG) from a Blob</title>
<link rel="stylesheet" href="node_modules/ol/ol.css">
<style>
.map {
width: 100%;
height: 400px;
}
</style>
</head>
<body>
<div id="map" class="map"></div>
<!-- Pointer events polyfill for old browsers, see https://caniuse.com/#feat=pointer -->
<script src="https://cdn.jsdelivr.net/npm/elm-pep@1.0.6/dist/elm-pep.js"></script>
<script type="module" src="main.js"></script>
</body>
</html>