let img_file = BufReader::new(File::open("N265E425.tif").unwrap());
let mut tiff = GeoTiffReader::open(img_file).unwrap();
match tiff.read_pixel(x, y) {
    RasterValue::U16(v) => println!("Height: {v}"),
    _ => println!("Unexpected pixel type"),
};

let img_file = BufReader::new(File::open("N265E425.tif").unwrap());
let mut tiff = GeoTiffReader::open(img_file).unwrap();
let (x0, y0, w, h) = (2500, 3000, 100, 100);
let mut img = ImageBuffer::new(w, h);
for (x, y, pixel) in tiff.pixels(x0, y0, w, h) {
    if let RasterValue::U16(v) = pixel {
        img.put_pixel(x - x0, y - y0, image::Luma([v]));
    }
}
img.save("dtm.png").unwrap();