antv-l7/examples/raster/basic/demo/ndvi.js

68 lines
1.8 KiB
JavaScript

// https://gw.alipayobjects.com/zos/antvdemo/assets/2019_clip/ndvi_201905.tif
import { RasterLayer, Scene } from '@antv/l7';
import { GaodeMap } from '@antv/l7-maps';
import * as GeoTIFF from 'geotiff';
const scene = new Scene({
id: 'map',
map: new GaodeMap({
pitch: 0,
style: 'dark',
center: [ 115.5268, 34.3628 ],
zoom: 3
})
});
scene.on('loaded', () => {
addLayer();
});
// async function getAllYearData() {
// const allData = [];
// for (let i = 1; i < 13; i++) {
// const month = i < 10 ? '0' + i : i;
// const res = await getTiffData(month);
// allData.push(res);
// }
// return allData;
// }
async function getTiffData(month) {
const response = await fetch(
'https://gw.alipayobjects.com/zos/antvdemo/assets/2019_clip/ndvi_2019' + month + '.tiff'
);
const arrayBuffer = await response.arrayBuffer();
const tiff = await GeoTIFF.fromArrayBuffer(arrayBuffer);
const image = await tiff.getImage();
const width = image.getWidth();
const height = image.getHeight();
const values = await image.readRasters();
return {
data: values[0],
width,
height
};
}
async function addLayer() {
const layer = new RasterLayer();
const tiffdata = await getTiffData('06');
layer
.source(tiffdata.data, {
parser: {
type: 'raster',
width: tiffdata.width,
height: tiffdata.height,
extent: [ 73.4766000000000048, 18.1054999999999993, 135.1066187, 57.6300460 ]
}
})
.style({
opacity: 0.8,
clampLow: false,
clampHigh: false,
domain: [ -3000, 10000 ],
rampColors: {
colors: [ 'rgb(166,97,26)', 'rgb(223,194,125)', 'rgb(245,245,245)', 'rgb(128,205,193)', 'rgb(1,133,113)' ],
positions: [ 0, 0.25, 0.5, 0.75, 1.0 ]
}
});
scene.addLayer(layer);
}