myweather

#!/bin/bash
#
# myweather
# usage: myweather --help
# Requires active internet connection
#
# yaswant.pradhan (Feb 2015)
# 2015-07-22: v-0.1: Beta release (yp)
# 2015-08-14 v1.0: First stable release with minor bug fixes (yp)
# 2016-01-25 v1.1: Fix error for non-reporting Tdew/RH stations (yp)
# -----------------------------------------------------------------------------
# set -e
VERSION=1.1

# -----------------------------------------------------------------------------
# Create a local database file to store METAR/TAF station details
# -----------------------------------------------------------------------------
user=$(id -u -n)                            # user name
DBHOME=$(readlink -m ~)/.myweather          # user home
mkdir -p $DBHOME

# -----------------------------------------------------------------------------
# Download stations database files
# -----------------------------------------------------------------------------
ccccURL='https://drive.google.com/uc?export=download&id=0B6qnynyDdeRjLVpWUko4NG9lTms'
bbsssURL='https://drive.google.com/uc?export=download&id=0B6qnynyDdeRjZThRNWtDbFNJX3M'
ccccfile='nsd_cccc.txt'
bbsssfile='nsd_bbsss.txt'

if [ ! -f "$DBHOME/$ccccfile" ] \
  || test $(find $DBHOME -name "$ccccfile" -mtime +30); then

    echo -e "Updating cccc database.. \c"
    cd $DBHOME && curl -sL $ccccURL > $ccccfile
    [[ $? -eq 0 ]] && echo -e "done." || echo $?
fi

if [ ! -f "$DBHOME/$bbsssfile" ] \
  || test $(find "$DBHOME" -name "$bbsssfile" -mtime +30); then

    echo -e "Updating bbsss database.. \c"
    cd $DBHOME && curl -sL $bbsssURL > $bbsssfile
    [[ $? -eq 0 ]] && echo -e "done." || echo $?
fi

CURL_OPT='-C - --retry 2 -m 60 '

# -----------------------------------------------------------------------------
# Get weather data
# -----------------------------------------------------------------------------
METAR_URL='ftp://tgftp.nws.noaa.gov/data/observations/metar/decoded/'
SYNOP_URL='http://www.ogimet.com/cgi-bin/getsynop'
datfile='/var/tmp/weather.met'
stnfile='/var/tmp/weather.stn'

hr(){ for i in {1..68}; do echo -e '-\c'; done; echo; }
version(){
cat<<EOF
${0##*/}: version-$VERSION

Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SYNOP and METAR reports are obtained from http://www.ogimet.com and ftp://tgftp.nws.noaa.gov respectively.

Written by Yaswant Pradhan.
EOF
}
usage(){
more<<EOF
${0##*/} prints recent past weather summary based on METAR/SYNOP observations for a given SYNOP/METAR/TAF location.

Usage: ${0##*/} [OPTION] [Station]

Arguments:
  Station             Station ID can be any one of the following:
    - a SYNOP 5 digit code (eg. 03839 for Exeter Airport), or
    - an ICAO 4 caracter code (eg. EGTE for Exeter Airport), or
    - part of stations or country name (use -i to ignore case)

Options:
  -h, -?, --help      show this message
  -i, --ignore-case   recursively search (ignore case while searching the location database) any matching patterns from stationid argument.
  -r, --reset         reset default station
  -s, --synop         display weather summary based on SYNOP report. def: METAR report
  -v, --version       print version number and exit

Report bugs to <yaswant.pradhan>
EOF
}


GREPOPT=
syn=
while [[ $1 == -* ]]; do
  case $1 in
    -h|--help|-\?) usage; exit 0;;
    -i|--ignore-case) GREPOPT='-i'; shift 1;;
    -r|--reset) rm -f $DBHOME/default.station; shift 1;;
    -s|--synop) syn=1; shift 1;;
    -v|--version) version; exit 0;;
    --) shift; break;;
    -*) echo -e "\nE: invalid option $1\n"; usage; exit 1;;
  esac
done

# Set Default station (required first time):
if [[ $# -eq 0 ]]; then
  if [ ! -f $DBHOME/default.station ]; then
    read -s -n1 -p "Do you wish to set default station? [Y/n] " key

    case $key in
      "Y" | "y")
        printf "\nPlease enter the 4 digit ICAO code";
        printf " (see $DBHOME/$ccccfile): ";
        read def_stn ;
        echo $def_stn > $DBHOME/default.station;
        printf "\n** Info: Your default station is now set to $def_stn **\n" ;;

      "N" | "n" | *)
        printf "\nUsing program default station EGTE\n";
        def_stn=EGTE ;;
      #*) echo "Not so cool" && exit ;;
    esac

  else
    def_stn=$(cat "$DBHOME/default.station")
  fi
fi


STN=${1:-$def_stn}

if [[ "$syn" -eq 1 ]]; then ## Return combined country-code and station-id

  cat $DBHOME/$bbsssfile |grep $GREPOPT "$STN" > $stnfile
  STNID=( $(cat $stnfile |awk -F ";" '{printf "%s%s ",$1,$2}') )
  stat=$?
  if [[ "$stat" -eq 0 ]]; then
    ii=0

    while read -r line || [[ -n $line ]]; do
      station_name[ii]=$(echo $line |cut -d';' -f4)
      country_name[ii]=$(echo $line |cut -d';' -f6)
      lat[ii]=$(echo $line | awk -F"[;]" '{printf "%s", $8}')
      lon[ii]=$(echo $line | awk -F"[;]" '{printf "%s", $9}')
      elev[ii]=$(echo $line | awk -F"[;]" '{printf "%s", $12}')
      alt_code[ii]=$(echo $line | awk -F ";" '{printf "%s",$3}')
      ii=$((ii + 1))
    done < $stnfile

  fi
else  ## Return ICAO code
  cat $DBHOME/$ccccfile | grep $GREPOPT "$STN" > $stnfile
  STNID=( $(cat $stnfile | cut -d";" -f1) ); stat=$?
  if [[ "$stat" -eq 0 ]]; then
    ii=0

    while read -r line || [[ -n $line ]]; do
      station_name[ii]=$(echo $line | cut -d';' -f4)
      country_name[ii]=$(echo $line | cut -d';' -f6)
      lat[ii]=$(echo $line | awk -F"[;]" '{printf "%s", $8}')
      lon[ii]=$(echo $line | awk -F"[;]" '{printf "%s", $9}')
      elev[ii]=$(echo $line | awk -F"[;]" '{printf "%s", $12}')
      alt_code[ii]=$(echo $line | awk -F ";" '{printf "%s%s",$2,$3}')
      ii=$((ii + 1))
    done < $stnfile

  fi
fi

[[ "$stat" -ne 0 ]] && exit $stat
[[ ${#STNID[@]} -eq 0 ]] \
  && echo "No record found. Tip: use -i option to ignore case OR \
provide exact ICAO airport code or SYNOP station id."

# Now return decoded weather information
k=1
c=0

nStns="${#STNID[@]}"
for i in ${STNID[@]}; do
  echo -e "\n[$k] ${station_name[c]}, ${country_name[c]}\
  (${lat[c]}/${lon[c]}  Elevation:${elev[c]}m)"

  if [[ "$syn" -ne 1 ]]; then
  # ---------------------------------------------------------------------------
  #                 METAR Report
  # ---------------------------------------------------------------------------
    curl --fail "${METAR_URL}${i}.TXT" &>/dev/null

    if [[ "$?" -eq 0 ]]; then

      curl $CURL_OPT -s "${METAR_URL}${i}.TXT" > "$datfile"

      if [[ "$?" -eq 0 ]]; then
        dt=($(head -n 2 $datfile | tail -n 1 | awk '{printf "%s %s",$9,$10}'))
        hh=$(echo ${dt[1]} | cut -c1-2)
        mn=$(echo ${dt[1]} | cut -c3-4)

        hr;
        printf "%63s\n" \
"Weather summary at ${STNID[c]} / ${alt_code[c]} on ${dt[0]} at $hh:$mn UTC"
        hr;

        cat $datfile | head -n -2 | tail -n +3 \
          | awk -F ":" '{printf " %20s:%s\n",$1,$2}'
      fi

    else
        echo "** E: No METAR for ($i) ${alt_code[c]} **"
        nStns=$(( nStns - 1 ))
    fi
  else
  # ---------------------------------------------------------------------------
  #                 SYNOP Report
  # ---------------------------------------------------------------------------
    cHour=$(date -u +%H)
    [[ "10#$cHour" -eq 0 ]] \
      && begin0=$(date -d 'yesterday' +'%Y%m%d')0000 \
      || begin0=$(date +'%Y%m%d')0000

    BEGIN=${2:-"$begin0"} # TODO: add an option to keep the raw reports

    curl --fail "${SYNOP_URL}?begin=${BEGIN}&block=${STNID[c]}" &>/dev/null

    if [[ "$?" -eq 0 ]]; then
      curl $CURL_OPT -s \
        "${SYNOP_URL}?begin=${BEGIN}&block=${STNID[c]}" > $datfile

      if [[ "$?" -eq 0 ]] && [[ $(cat $datfile | wc -l) -ne 0 ]] ; then

        rep=$(tail -1 $datfile)

        dt=($(echo $rep \
              | awk -F "," '{printf "%s.%s.%s %s:%s", $2,$3,$4,$5,$6}'))

        hr
        printf "%63s\n" \
"Weather summary at ${STNID[c]} / ${alt_code[c]} on ${dt[0]} at ${dt[1]} UTC"
        hr

        # Decode/estimate SYNOP report
        ## 1. Temperature:
        tempC=$(echo $rep | awk '{print $6}')
        id=$(echo $tempC | cut -c1)
        sn=$(echo $tempC | cut -c2)
        [[ "$id" -eq 1 ]] && \
            T=$(echo $tempC | cut -c3-5 | awk '{print $1/10}')
        [[ "$sn" -eq 1 ]] && T=-"${T}"
        cT=$(echo -e "${T} \xc2\xb0C")

        ## 2. Dew point temp or RH:
        tempC=$(echo $rep | awk '{print $7}')
        id=$(echo $tempC | cut -c1)
        sn=$(echo $tempC | cut -c2) # sign of temp (0=positive, 1=negative, 9=RH)

        ## Print result
        # 1. Temperature
        echo -e " Temperature: $cT" | awk -F ":" '{printf" %20s:%s\n",$1,$2}'

        # 2. Dew Point and RH
        if [[ $sn =~ ^-?[0-9]+$ ]]; then
            [[ "$id" -eq 2 ]] && cDP=$(echo $tempC | cut -c3-5) || break
            if [[ "$sn" -eq 9 ]]; then
                cRH=$cDP
            else
              # Calculate RH from DewPoint temp
              # See http://andrew.rsmas.miami.edu/bmcnoldy/Humidity.html
              tdok=1
              [[ "$sn" -eq 1 ]] && td=-$cDP || td=$cDP
              cRH=$(echo "100*e((17.625*"$td"/10)/(243.04+"$td"/10)) / \
                          e((17.625*"$T")/(243.04+"$T"))" | bc -l)
            fi
            [[ "$tdok" -eq 1 ]] \
              && td=$(echo "$td" | awk '{print $1/10}')
            echo -e " Dew Point: $td \xc2\xb0C" \
              | awk -F ":" '{printf" %20s:%s\n",$1,$2}'
            echo -e " Relative humidity: $cRH" \
              | awk -F ":" '{printf" %20s: %.1f %%\n",$1,$2}'
        fi

      else
        echo "    E: No SYNOP for $i (${alt_code[c]})"
        nStns=$(( $nStns - 1 ))
      fi

    else
        echo "    E: No SYNOP for $i (${alt_code[c]})"
        nStns=$(( nStns - 1 ))
    fi

  fi

  c=$((c + 1))
  k=$((k + 1))

done


# Housekeep:
[[ "$nStns" -gt 1 ]] \
  && echo -e "\n\n Valid (Total) Stations: $nStns (${#STNID[@]})"
rm -f $datfile $stnfile