dem-tiler.ts

import { output, processImage } from "@thi.ng/imago";
import { GRAY8 } from "@thi.ng/pixel";
import { readGeoTiff } from "@thi.ng/pixel-io-geotiff";
import { range2d } from "@thi.ng/transducers";
import { readFileSync } from "node:fs";

// a 44155 x 25153 pixel GeoTIFF file
const path = "DOM_Tirol_5m_epsg31254/DOM_Tirol_5m_epsg31254_2017-2023.tif";

// load GeoTIFF
const { img } = await readGeoTiff(readFileSync(path), { clamp: [0, 4000], pool: 8 });

const { width, height } = img;
const size = 4096;

// extract tiles and export as PNG images
for (let [x, y] of range2d(0, width, 0, height, size, size)) {
	const tile = img.getRegion(x, y, size, size);
	await processImage(tile!.as(GRAY8), [
		output({ id: "main", path: `tile-${x}-${y}.png` }),
	]);
}