- By night, colour and rhythm of light and/or illumination enhancement.
- By day, colour, shape, top-mark, and/or light (including colour and rhythm).
- By electronic (digital) symbology, e.g. as a complement to physical marks.
- By electronic (digital) symbology solely.
In which date IALA full meaning has been changed? can anyone give me the correct information…
Previously It was International Association of Light house authority. But now it is International Association of marine aids to navigation Lighthouse Authorities (IALA) is a non profit international technical association.