pyramid from asc

mkdir ${TARGET_DIR}_tif
echo "building ${BIG_TIF}.tif"
find . -iname '*.asc' -type f | xargs gdal_merge.py -o ${TARGET_DIR}_tif/${BIG_TIF}.tif -co "TILED=YES" -co "BLOCKXSIZE=512" -co "BLOCKYSIZE=512" -co "COMPRESS=DEFLATE" -co "ZLEVEL=9" -init -9999 -a_nodata -9999 -n -9999 -ot Int16

echo "assigning srs to ${BIG_TIF}.tif"
gdal_translate -a_nodata 0 -ot Int16  -a_srs "EPSG:2154" -co "TILED=YES" -co "BLOCKXSIZE=512" -co "BLOCKYSIZE=512" -co "COMPRESS=DEFLATE" -co "ZLEVEL=9" ${TARGET_DIR}_tif/${BIG_TIF}.tif ${TARGET_DIR}_tif/${BIG_TIF}_CRS.tif
mv ${TARGET_DIR}_tif/${BIG_TIF}_CRS.tif ${TARGET_DIR}_tif/${BIG_TIF}.tif

echo "building pyramid"
mkdir $TARGET_DIR
gdal_retile.py -v -r bilinear -levels 6 -ps 2048 2048  -ot Int16 -co TILED=YES -co COMPRESS=DEFLATE -targetDir $TARGET_DIR ${TARGET_DIR}_tif/${BIG_TIF}.tif

cd $TARGET_DIR
mkdir 0
mv *.tif 0/

cd -