ANLYSS is the average station spacing and the grid extend region
separated by a slash:
station spacing / grid extend region
This information is retrieved from the grid file and used in the
objective analysis programs.
The station spacing is in degrees of latitude and is used to compute
the weighting functions in the Barnes analysis programs. The
default for the station spacing is twice the grid spacing.
The grid extend area is specified by four integers, separated by
semicolons, which are the numbers of grid points to extend the grid
left, down, right, and up. Only data within the extended grid area
is used after the first Barnes pass. The default for the grid extend
region is 2;2;2;2.