What is this sign

[super]

What is this sign with capital letter on the platform?

[Japan Station]

Looks like lavender. Can you tell us where you tell us where you found this sign?

[super]

I know it's a lavender, but I'm wondering what does it mean? There is a sign for L with lavender, M with melon and I with iris picture....at Shin-Hakodate-Hokuto station. Does it stand for something special section of Shinkansen? 

[Japan Station]

There is a Lavender Farm station in Hokkaido, but it's not connected to Shin-Hakodate-Hokuto. http://www.farm-tomita.co.jp/en/access/station.asp

In this case it's probably used to indicate a section of the platform to simplify navigation.