ZEROM  Constructs a regular matrix map of all zeros.

  map = ZEROM(latlim,lonlim,scale) constructs a regular matrix
  map of all 0's.  The inputs are the latitude and longitude limits
  as 2 element vectors, and a scale factor.  The latitude and longitude
  limits are in degrees.  The scale factor represents the number of
  matrix entries per single unit of latitude and longitude (eg:  10
  entries per degree, 100 entries per degree).  The scale input must
  be scalar.

  [map,maplegend] = ZEROM(...) returns the maplegend vector for the
  constructed regular matrix map.

  See also NANM, SPZEROM, ONEM, ZEROS