Negative values stands for years before Christus. Use this variable to specify the object, for wich the plot is calculated.
Negative values stands for southern latitudes, positive for northern.
Note, that the timezone is set to zero, if latitude was set. You should set the timezone in a following parameter. Negative values stands for western latitudes, positive for eastern. Note, that the timezone is set to zero, if longitude was set. You should set the timezone in a following parameter.