Geographic Flag for Cardiff, Wales at: 3 Degrees West by 51 Degrees North
The Geographic Flag for Cardiff, Wales has a yellow fly bar, that is coded to number. Since Yellow is the 3rd colour of the rainbow and Cardiff is on the 3rd Meridian West - we see a yellow fly bar. Also the blue and red star are coded to Cardiff's Longitude: 51 Degrees North. Reason being blue is the 5th colour and red is the 1st colour of the rainbow.