GDAL Convert CMAQ to GeoTIFF

cmaq_gdal_translate.sh

#!/usr/bin/env bash
INPATH=${1?Required input CMAQ File}
if [[ ${INPATH} == "-h" || ${INPATH} == "--help" ]]; then
   echo $0 [-h] INPATH INVAR [OUTPATH]
   echo "Convert CMAQ IOAPI meta data to SRS and create raster using gdal_translate"
   echo "  -h --help: print this help menu"
   echo "  INPATH   : path to CMAQ input/output file"
   echo "  INVAR    : name of variable in INPATH"
   echo "  OUTPATH  : Path for output raster (default: INPATH_INVAR.tif)"
   exit
fi
INVAR=${2?Input Variable from CMAQ File}
OUTPATH=$(basename ${INPATH})_${INVAR}.tif
OUTPATH=${3:-${OUTPATH}}
# Grab GLOBAL VARS
# awk is used to find lines for key global attributes and set value
# to interal variable. Then print variables to create a declarations string
INGLBL=$(gdalinfo ${INPATH} | awk -F"=" '
  /^  NC_GLOBAL#GDTYP=/ { GDTYP=$2 }
  /^  NC_GLOBAL#P_ALP=/ { P_ALP=$2 }
  /^  NC_GLOBAL#P_BET=/ { P_BET=$2 }
  /^  NC_GLOBAL#XCELL=/ { XCELL=$2 }
  /^  NC_GLOBAL#XCENT=/ { XCENT=$2 }
  /^  NC_GLOBAL#YCENT=/ { YCENT=$2 }
  /^  NC_GLOBAL#XORIG=/ { XORIG=$2 }
  /^  NC_GLOBAL#YORIG=/ { YORIG=$2 }
  /^  NC_GLOBAL#NCOLS=/ { NCOLS=$2 }
  /^  NC_GLOBAL#NROWS=/ { NROWS=$2 }
  END {
    print "GDTYP="GDTYP
    print "P_ALP="P_ALP
    print "P_BET="P_BET
    print "XCELL="XCELL
    print "XCENT="XCENT
    print "YCENT="YCENT
    print "XORIG="XORIG
    print "YORIG="YORIG
    print "NCOLS="NCOLS
    print "NROWS="NROWS
    print "x_0="(XORIG * -1)
    print "y_0="(YORIG * -1)
    print "stere_lat_0="(P_ALP * 90)
  }
')
declare $INGLBL
# We should define at least polar stereographic and lamber conic conformal (lcc)
# currently only LCC was tested.
if [ ${GDTYP} == "2" ]; then
    CRS_PROJ4="+proj=lcc +lat_1=${P_ALP} +lat_2=${P_BET} +lat_0=${YCENT} +lon_0=${XCENT} +y_0=${y_0} +x_0=${x_0} +R=6370000 +to_meter=${XCELL} +no_defs"
elif [ ${GDTYP} == "6" ]; then
    CRS_PROJ4="+proj=stere +lat_0=${stere_lat_0} +lat_ts=${P_BET} +lon_0=${XCENT} +x_0=${x_0} +y_0=${y_0} +R=6370000 +to_meter=${XCELL} +no_defs"
elif [ ${GDTYP} == "7" ]; then
    CRS_PROJ4="+proj=merc +lat_ts=0 +lon_0=${XCENT} +x_0=${x_0} +y_0=${y_0} +R=6370000 +to_meter=${XCELL} +no_defs"
else
  echo "GDTYP=${GDTYP} has not been implemented"
  exit 1
fi
echo CRS_PROJ4=\"${CRS_PROJ4}\"
gdal_translate -a_ullr 0 ${NROWS} ${NCOLS} 0 -a_srs "${CRS_PROJ4}" NETCDF:${INPATH}:${INVAR} -b 1 ${OUTPATH}