Get lat/lon values from filename.

def parseFilename(self, filename):
        """Get lat/lon values from filename."""
        match = self.filename_regex.match(filename)
        if match is None:
            # TODO?: Raise exception?
            '''print("Filename", filename, "unrecognized!")'''
            return None
        lat = int(match.group(2))
        lon = int(match.group(4))
        if match.group(1) == "S":
            lat = -lat
        if match.group(3) == "W":
            lon = -lon
        return lat, lon