植被指数

// @ts-ignore
import { RasterLayer, Scene } from '@antv/l7';
// @ts-ignore
import { Map } from '@antv/l7-maps';

import * as GeoTIFF from 'geotiff';

async function getTiffData(url: string) {
  const response = await fetch(url);
  const arrayBuffer = await response.arrayBuffer();
  const tiff = await GeoTIFF.fromArrayBuffer(arrayBuffer);
  const image1 = await tiff.getImage();
  const bandsValues = await image1.readRasters();
  return bandsValues;
}

const scene = new Scene({
  id: 'map',
  map: new Map({
    center: [130.5, 47],
    zoom: 10.5,
  }),
});

scene.on('loaded', async () => {
  const url1 = 'https://gw.alipayobjects.com/zos/raptor/1667832825992/LC08_3857_clip_2.tif';
  const tiffdata = await getTiffData(url1);
  const url2 = 'https://t0.tianditu.gov.cn/img_w/wmts?tk=b72aa81ac2b3cae941d1eb213499e15e&';

  const layer2 = new RasterLayer({
    zIndex: 1,
  }).source(url2, {
    parser: {
      type: 'rasterTile',
      tileSize: 256,
      wmtsOptions: {
        layer: 'img',
        tileMatrixset: 'w',
        format: 'tiles',
      },
    },
  });
  // NDBI 6,5
  // NDWI 3,5
  const layer = new RasterLayer({
    zIndex: 10,
  });

  layer
    .source(tiffdata, {
      parser: {
        type: 'ndi',
        width: tiffdata.width,
        height: tiffdata.height,
        bands: [3, 4],
        extent: [130.39565357746957, 46.905730725742366, 130.73364094187343, 47.10217234153133],
      },
    })
    .style({
      domain: [-0.3, 0.5],
      rampColors: {
        colors: ['#ce4a2e', '#f0a875', '#fff8ba', '#bddd8a', '#5da73e', '#235117'],
        positions: [0, 0.2, 0.4, 0.6, 0.8, 1.0],
      },
    });

  scene.addLayer(layer2);
  scene.addLayer(layer);
});