Frequently Asked Questions

1. What is the polar stereographic projection?
   
   The polar stereographic projection was initially used with ice concentration products developed at the NASA Goddard Space Flight Center (GSFC) and has been retained for historical consistency. It specifies a projection plane tangent to the earth at 70° northern and southern latitude, which was selected so that little or no distortion would occur in the marginal ice zone. For more information, please see the Polar Stereographic Projection and Grid documentation.
    
2. What is the spatial resolution of the polar stereographic projection?
   
   The spatial resolution of NSIDC data sets in the polar stereographic projection depends on the data set and is either 6.25 km, 12.5 km, or 25 km.