Table 4.

Decision table for image classification

Class	Sand cover	Shells cover	L. conchilega cover	Mussels cover	Unknown
Unknown (UN)	Irrelevant	Irrelevant	Irrelevant	Irrelevant	>= 4 quadrats
Bare sand (BS)	≥ 6 quadrats	Not used	None	None	Irrelevant
Bare sand with shells (BSS)	> 6 quadrats		None	None	Irrelevant
Shell dominated sand (SDS)	Irrelevant	≥ 6 quadrats	None	None	Irrelevant
Lanice Sparse (LS)	Irrelevant	Irrelevant	≤ 2 quadrats	None	Irrelevant
Lanice Patchy (LP)	Irrelevant	Irrelevant	2–6 quadrats	None	Irrelevant
Lanice Dominated (LD)	Irrelevant	Irrelevant	≥ 6 quadrats	None	Irrelevant
Mussel Sparse (MS)	Irrelevant	Irrelevant	Irrelevant	≤ 2 quadrats	Irrelevant
Mussels Patchy (M)	Irrelevant	Irrelevant	Irrelevant	2–6 quadrats	Irrelevant
Mussel Dense bed (MD)	Irrelevant	Irrelevant	Irrelevant	≥ 6 quadrats	Irrelevant

When conditions for no. of quadrats (in bold) were met, the picture was categorised as such. “Unknown” class corresponds to the impossibility of seabed feature’s identification (more than 4/8 unknown quadrats)