Table 4. The format and field descriptions of data records containing all grid cells marked as cropland.

Variable	Type	Description	Example
location_id	Numeric, continuous	Unique number identifying each location in the campaign.	47286
userid	Numeric, continuous	Numeric field used to uniquely identify participants/users	11182
sub_id	Numeric, continuous	Sequentially assigned number identifying every submission done in the system	383725
comment	Text	Comments entered by the participant	Apparent pastures
timestamp	Date and time	Exact time and date when the submission was entered into the system	2016-09-16 13:20:19
used_gmaps	Yes=‘t’No=‘f’	Registers whether the participant was viewing the Google background imagery when the submission was done	t
viewed_ge	Yes=‘t’No=‘f’	Registers whether the participant pressed the button labelled View in Google Earth	f
skip_reason	Numeric, categorical	Registers whether the participant did not skip the point (Skip=0), skipped the point and used the reason ‘no img. available/ low resolution/ clouds’ (Skip=1), or skipped the point and used the reason ‘too difficult’ (Skip=2)	0
sub_item_id	Numeric, continuous	Unique identifier of each grid cell classified as cropland at a given location by a given user	10579829
sub_item_x	Numeric, continuous	Longitude of each grid cell centroid inside a frame/location (decimal degrees)	30.95357144
sub_item_y	Numeric, continuous	Latitude of each grid cell centroid inside a frame/location (decimal degrees)	−20.75119048