About Lon_S
Lon_S is an analysis export variable.
It reports the longitude (in decimal degrees) of the first ping in the domain which was analyzed (S for Start).
This variable is exported only if it is selected on the Export page of the EV File Properties dialog box.
See also
About analysis
About analysis variables
About ping position
About Lat_E
About Lat_M
About Lat_S
About Lon_E
About Lon_M