Decode TEMP ship reports in TAC

decode_temp_ship.py

import os
import sys


def decode_meta(rep):
    dd = rep[2][:2]
    hh = rep[2][2:4]
    lat = int(rep[6][2:]) * 0.1
    lon = int(rep[7][1:]) * 0.1
    meta = {"dd":dd, "hh":hh, "vessel":rep[4], "lon":lon, "lat":lat}
    return meta

def decode_pres(fld, pmin=200):
    p = int(fld[2:])
    if p < pmin: p += 1000
    return p

def decode_preshgt(fld, pmin=200):
    lev = fld[:2]
    if lev == "99":
        p = decode_pres(fld)
        z = 0.0
    else:
        p = int(lev)
        p *= 10
        if p == 0: p = 1000
        if p == 920: p +=5
        z = int(fld[2:])
        if p == 850: z += 1000
        elif p == 700:
            if z > 500: z+= 2000
            else: z+= 3000
        elif p <= 500 and p >= 300: z *= 10
        elif p <= 250 : z = (z + 1000) * 10
    return p, z

def negate_odd(T):
    return -2 * (T % 2) + 1

def decode_ttd(fld):
    if fld != "/////":
        T = int(fld[:3])
        T = negate_odd(T) * T * 0.1
        TTdstr = fld[3:5]
        if TTdstr != "//":
            Td = T - int(TTdstr) * 0.1
        else:
            Td = float("nan")
    else:
        T, Td = float("nan"), float("nan")
    return T, Td

def decode_wind(fld):
    dstr = fld[:3]
    if fld[:3] != "///":
        d = int(dstr)
        dmod5 = d % 5
        d = d - dmod5
        sstr = fld[3:5]
        if sstr != "///":
            s = int(sstr) + dmod5 * 100
        else:
            s = float("nan")
    else:
        d = float("nan")
    return d, s

def decode_sst(fld):
    sst = int(fld[2:5]) * 0.1
    if fld[1] != "0": sst *= -1
    return sst

def decode_aa(rep, r=9):
    pres = []
    ghgt = []
    tcel = []
    tdew = []
    dire = []
    magn = []
    while rep[r][:2] != "88":
        p, z = decode_preshgt(rep[r])
        pres.append(p)
        ghgt.append(z)
        T, Td = decode_ttd(rep[r+1])
        tcel.append(T)
        tdew.append(Td)
        d, s = decode_wind(rep[r+2])
        dire.append(d)
        magn.append(s)
        r += 3
    while rep[r] != "31313": r +=1
    while rep[r][0] != "9" : r +=1
    sst = decode_sst(rep[r])
    return pres, ghgt, tcel, tdew, dire, magn, sst

def decode_bb(rep, r=9):
    prst = []
    tcel = []
    tdew = []
    prsw = []
    dire = []
    magn = []
    while rep[r] != "21212":
        p = decode_pres(rep[r])
        prst.append(p)
        T, Td = decode_ttd(rep[r+1])
        tcel.append(T)
        tdew.append(Td)
        r += 2
    r += 1
    while rep[r] != "31313":
        p = decode_pres(rep[r])
        prsw.append(p)
        d, s = decode_wind(rep[r+1])
        dire.append(d)
        magn.append(s)
        r += 2
    while rep[r][0] != "9" : r +=1
    sst = decode_sst(rep[r])
    while rep[r] != "61616": r +=1
    r +=1
    while True:
        p = decode_pres(rep[r])
        prsw.append(p)
        d, s = decode_wind(rep[r+1])
        dire.append(d)
        magn.append(s)
        if rep[r+1][-1] == "=":
            break
        else:
            r += 2
    return prst, tcel, tdew, prsw, dire, magn, sst

def save_csv(outfname, meta, *record):
    with open(outfname, "w") as g:
        g.write(f"{meta['vessel']},{meta['dd']},{meta['hh']},{meta['lon']},{meta['lat']},{meta['sst']}\n")
        for t in zip(*record):
            r = ",".join(map(str,t)) + "\n"
            g.write(r)

if __name__ == "__main__":
    vessel_set = {"7JJW", "7JEJ", "7KBR", "7JAI"} # edit as needed
    debug = False
    if len(sys.argv) < 3:
        print(f"Usage :: python {sys.argv[0]} infname outdir")
        sys.exit()
    infname = sys.argv[1]
    outdir = sys.argv[2]
    print(infname, outdir)
    with open(infname, "r") as f:
        rep = f.read().split()
        meta = decode_meta(rep)
        print(meta)
        if meta["vessel"] in vessel_set:
            part = rep[3][2:]
            print(part)
            if part == "AA":
                pres, ghgt, tcel, tdew, dire, magn, sst = decode_aa(rep)
                meta["sst"] = sst
                if debug:
                    for p, z, T, Td, d, s in zip(pres, ghgt, tcel, tdew, dire, magn):
                        print(p, z, T, Td, d, s)
                print(meta)
                outfname = f"{meta['vessel']}-{meta['dd']}{meta['hh']}_{part}.csv"
                outfname = os.path.join(outdir, outfname)
                print(outfname)
                save_csv(outfname, meta, pres, ghgt, tcel, tdew, dire, magn)
            if part == "BB":
                prst, tcel, tdew, prsw, dire, magn, sst = decode_bb(rep)
                meta["sst"] = sst
                print(meta)
                if debug:
                    for p, T, Td in zip(prst, tcel, tdew):
                        print(p, T, Td)
                    for p, d, s in zip(prsw, dire, magn):
                        print(p, d, s)
                print(sst)
                outfname = f"{meta['vessel']}-{meta['dd']}{meta['hh']}_{part}_temp.csv"
                outfname = os.path.join(outdir, outfname)
                print(outfname)
                save_csv(outfname, meta, prst, tcel, tdew)
                outfname = f"{meta['vessel']}-{meta['dd']}{meta['hh']}_{part}_wind.csv"
                outfname = os.path.join(outdir, outfname)
                print(outfname)
                save_csv(outfname, meta, prsw, dire, magn)