DwC rank determiner.

rank.py

def is_number(s):
    try:
        float(s)
        return True
    except ValueError:
        return False    

def valid_latlng(lat,lng):
    # accepts lat and lng as strings.
    if not is_number(lat):
        return False
    if not is_number(lng):
        return False
    flat = float(lat)
    if flat < -90 or flat > 90:
        return False
    flng = float(lng)
    if flng < -180 or flng > 180:
        return False
    return True

def valid_georef(rec):
    if rec.has_key('decimallatitude'):
        if rec.has_key('decimallongitude'):
            return valid_latlng(rec['decimallatitude'],rec['decimallongitude'])
    return False

def valid_binomial(rec):
    if rec.has_key('genus'):
      if rec.has_key('specificepithet'):
        # Sufficient condition for now to have these DwC terms populated.
        # Later may want to test them against a name authority to determine validity.
        return True
    return False

def rank(rec):
    rank = 0
    if valid_georef(rec) is True and valid_binomial(rec) is True:
        rank = 5
        if rec.has_key('year'):
            rank = 6
            if rec.has_key('month'):
                rank = 7
                if rec.has_key('day'):
                    rank = 8
    elif valid_binomial(rec) is True:
        rank = 1
        if rec.has_key('year'):
            rank = 2
            if rec.has_key('month'):
                rank = 3
                if rec.has_key('day'):
                    rank = 4
    return rank