GMS-5/hdf/grid file description
 
  The grid extends from 80 degrees East longitude to 160 degrees West 
  longitude, with an interval of 0.5 degrees between points. Therefore 
  the number of columns required = 482 ( 241*2 --- since both the 
  line and pixel numbers for each point need to be stored ). Similarly 
  the number of rows required = 241 ( from 60 degrees North latitude to 
  60 degrees South latitude with an interval of 0.5 degrees )
 
GMS-5/hdf/grida file description
 
  Same format and dimension but the longitude grid is shifted 10 degrees 
  east to cover most of India. Extends from 70 E to 170W and 60N to 60S.