#!/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 25.22175632 56.9332973 -gcp 21600.0 0.0 25.2402349 57.02918264 -gcp 21600.0 22161.0 25.41380436 57.01446452 -gcp 0.0 22161.0 25.39378648 56.92706788 GX825/GX_825_SK_frame_68.jpg GX_825_SK_frame_68.vrt

# Add cutline to VRT
gdalwarp -r $GDAL_SAMPLING_WARP -tps -dstalpha -cutline_srs EPSG:4326 \
  -cutline "POLYGON(($(echo -e "792.0 2280.0\n576.0 19344.0\n21096.0 19632.0\n21168.0 2328.0" | \
  gdaltransform -tps -output_xy GX_825_SK_frame_68.vrt | \
  awk 'NR==1{first=$0} {printf "%s %s,", $1,$2} END{print " " first}')))" \
  GX_825_SK_frame_68.vrt GX_825_SK_frame_68.cut.vrt

# Generate tiles
gdal2tiles.py -r $GDAL_SAMPLING_TILE --xyz -z $GDAL_TILE_ZOOMS -x --processes=$GDAL_TILE_PROCESSES GX_825_SK_frame_68.cut.vrt GX_825_SK_frame_68.xyz