lambert conformal conic projection with only 3 informations?

[Patrice Dumas]

Hello,

I have a netcdf file that is (as far as I can tell) in lambert conformal
conic projection grid, as I have in ncdump:

        char Lambert_conformal ;
                Lambert_conformal:grid_mapping_name = "lambert_conformal_conic" ;
                Lambert_conformal:longitude_of_central_meridian = "11.5" ;
                Lambert_conformal:latitude_of_projection_origin = "50.4" ;
                Lambert_conformal:standard_parallel = "11.5" ;

That means 3 informations about the projection.

However at http://www.iges.org/grads/gadoc/map.html#lambert (or
http://www.iges.org/grads/gadoc/pdef.html), there are 9

  latref        reference latitude
  lonref        reference longitude (in degrees, E is positive, W is negative)
  iref  i of ref point
  jref  j of ref point
  Struelat      S true lat
  Ntruelat      N true lat
  slon  standard longitude
  dx    grid X increment in meters
  dy    grid Y increment in meters

I can guess that latref and lonref and maybe slon corresponds with
(in random order) longitude_of_central_meridian,
latitude_of_projection_origin and standard_parallel, but what about
the others?

I am completly ignorant on the subject, so I may be completly
missing something.

Any idea on how the other parameters can be computed, if possible?

--
Pat