c_tp->course = g_ascii_strtod ( c_cdata->str, NULL );
g_string_erase ( c_cdata, 0, -1 );
break;
case tt_trk_trkseg_trkpt_speed:
c_tp->course = g_ascii_strtod ( c_cdata->str, NULL );
g_string_erase ( c_cdata, 0, -1 );
break;
case tt_trk_trkseg_trkpt_speed: