Table 2.

Significance tests were performed on all skyline datasets between 7:00 and 20:00 to compare their classification rates. We used bootstrapping [38] as the statistical test; for details, see Section 3.1.1. The shown significance values are $99.9\%$ (***), $99\%$ (**) and $95\%$ (*); for the databases forest/suburban and all, all significance tests are highly significant ($99.9\%$).

Stones	${\mathbf{NA}}_{{90}^{\circ },\mathit{\lambda }}$	UV	Green	Contrast	Fisher	Mask
${\mathrm{NA}}_{{90}^{\circ },\lambda }$		***	***	***	***	***
UV			***	***	-	-
Green				***	***	***
Contrast					***	***
Fisher						-
Mask
Sand	${\mathbf{NA}}_{{90}^{\circ },\mathit{\lambda }}$	UV	Green	Contrast	Fisher	Mask
${\mathrm{NA}}_{{90}^{\circ },\lambda }$		***	***	***	***	***
UV			***	***	-	***
Green				***	***	***
Contrast					***	***
Fisher						-
Mask
Earth	${\mathbf{NA}}_{{90}^{\circ },\mathit{\lambda }}$	UV	Green	Contrast	Fisher	Mask
${\mathrm{NA}}_{{90}^{\circ },\lambda }$		***	***	***	***	***
UV			***	***	-	**
Green				***	***	***
Contrast					***	***
Fisher						-
Mask