#!/bin/bash

GDAL_TILE_PROCESSES=16
GDAL_TILE_ZOOMS=8-14
GDAL_SAMPLING_WARP=cubic
GDAL_SAMPLING_TILE=antialias

# Create virtual dataset with coordinates
gdal_translate -of VRT -a_srs EPSG:4326 -outsize 300% 300% -gcp 0.0 0.0 25.05943358 56.9311894 -gcp 21600.0 0.0 25.08158226 57.02794217 -gcp 21600.0 21171.0 25.24524562 57.01262746 -gcp 0.0 21171.0 25.22593338 56.92353549 GX825/GX_825_SK_frame_72_copy_600_dpi.jpg GX_825_SK_frame_72_copy_600_dpi.vrt

# Add cutline to VRT
gdalwarp -r $GDAL_SAMPLING_WARP -tps -dstalpha -cutline_srs EPSG:4326 \
  -cutline "POLYGON(($(echo -e "816.0 1631.9197771587742\n20976.0 1296.0802228412258\n21216.0 19151.705849582177\n696.0 18816.173816155988" | \
  gdaltransform -tps -output_xy GX_825_SK_frame_72_copy_600_dpi.vrt | \
  awk 'NR==1{first=$0} {printf "%s %s,", $1,$2} END{print " " first}')))" \
  GX_825_SK_frame_72_copy_600_dpi.vrt GX_825_SK_frame_72_copy_600_dpi.cut.vrt

# Generate tiles
gdal2tiles.py -r $GDAL_SAMPLING_TILE --xyz -z $GDAL_TILE_ZOOMS -x --processes=$GDAL_TILE_PROCESSES GX_825_SK_frame_72_copy_600_dpi.cut.vrt GX_825_SK_frame_72_copy_600_dpi.xyz