@giro3d/giro3d/formats/GeoTIFFFormat.js

A JS/WebGL framework for 3D geospatial data visualization

import { fromBlob, Pool } from 'geotiff';
import { FloatType, UnsignedByteType } from 'three';
import TextureGenerator from '../utils/TextureGenerator';
import ImageFormat from './ImageFormat';
let geotiffWorkerPool;

/**
 * Decoder for TIFF images.
 *
 */
class GeoTIFFFormat extends ImageFormat {
  isGeoTIFFFormat = true;
  type = 'GeoTIFFFormat';
  /**
   * @param options - Decoder options.
   */
  constructor(options) {
    super(true, FloatType);
    this._enableWorkers = options?.enableWorkers ?? true;
  }

  /**
   * Decode a tiff blob into a
   * [DataTexture](https://threejs.org/docs/?q=texture#api/en/textures/DataTexture) containing
   * the elevation data.
   *
   * @param blob - the data to decode
   * @param options - the decoding options
   */

  async decode(blob, options) {
    const tiff = await fromBlob(blob);
    const image = await tiff.getImage();
    const height = image.getHeight();
    const width = image.getWidth();
    let dataType;
    const nodata = options?.noDataValue ?? image.getGDALNoData() ?? undefined;
    if (image.getBitsPerSample() === 8) {
      dataType = UnsignedByteType;
    } else {
      dataType = FloatType;
    }
    const spp = image.getSamplesPerPixel();

    // Let's use web workers to decode TIFF in the background
    if (window.Worker != null && geotiffWorkerPool == null) {
      geotiffWorkerPool = new Pool();
    }
    let inputBuffers;
    switch (spp) {
      case 1:
        {
          // grayscale
          const [v] = await image.readRasters({
            pool: geotiffWorkerPool
          });
          inputBuffers = [v];
        }
        break;
      case 2:
        {
          // grayscale with alpha
          const [v, a] = await image.readRasters({
            pool: geotiffWorkerPool
          });
          inputBuffers = [v, a];
        }
        break;
      case 3:
        {
          // RGB
          const [r, g, b] = await image.readRasters({
            pool: geotiffWorkerPool
          });
          inputBuffers = [r, g, b];
        }
        break;
      case 4:
        {
          // RGBA
          const [r, g, b, a] = await image.readRasters({
            pool: geotiffWorkerPool
          });
          inputBuffers = [r, g, b, a];
        }
        break;
      default:
        throw new Error(`unsupported channel count: ${spp}`);
    }
    const result = await TextureGenerator.createDataTextureAsync({
      width,
      height,
      nodata,
      enableWorkers: this._enableWorkers
    }, dataType, ...inputBuffers);
    return {
      texture: result.texture,
      min: result.min,
      max: result.max
    };
  }
}
export default GeoTIFFFormat;