Table 1.

Complementary geographic information layers, data sources and attributes extracted for landscape characterization

Geographic information layer	Information source	Method for layer creation	Remarks	Attributes extracted for virtual sites	Variable group
Buildings				Minimum distance to, Numberc	Anthropization
Asphalt roads, trails	Air photographsa	Manual digitizing (digitizing scale ≈ 1/5400)	Roads/trails accessible with a four-wheel drive vehicle	Minimum distance to (m), Length (m)c
Greenhouses				Minimum distance to, Numberc
Anthropogenic basins	Air photographsa and BD-Carto®;b		Basins may or may not be permanently flooded	Minimum distance to (m), Surface proportionc
Gold mining sites	Air photographsa and SPOT5 satellite images	Manual digitizing		Minimum distance to (m)
Permanent rivers (excluding the Comté River)	BD-Carto®;b			Minimum distance to (m), Length (m)c	Hydrology
Temporary rivers (excluding the Comté River)
Banks of the Comté River	Land cover map	GISd computation from the land cover map
Natural water surfaces	Air photographsa and BD-Carto®;b		May or may not be permanently flooded	Minimum distance to (m), Surface proportionc
Floodplains			Temporarily flooded
Altitude				Altitude (m)	Topography
Aspect (positive angle, in degree, relative to a west-east line)	SRTMe Digital Elevation Model	GISd computation from SRTM data		West-East orientation (cosine), South-North orientation (sinus)
Slope				Slope (%)

^aAerial photographs from BD-Ortho®; 2006 product (IGN, the French National Institute of Geographic and Forest Information).

^bBD-Carto®; 1:25,000 scale map (IGN product, 2006).

^cAttribute extracted within a 200 m radius buffer, centered on the virtual collection site.

^dGIS: Geographic Information System. The fee and open software used is GRASS GIS [18].

^eSRTM: Shuttle Radar Topography Mission (90 m spatial resolution).