Surfer can read the SRTM BIL and HGT data files directly. You can use the BIL or HGT files in any function or command in place of a grid file.
Surfer 11 and previous versions do not support HGT files, and Surfer 8 and previous do not support BIL files; however, both HGT and BIL files can be modified for use in these older versions of Surfer. Please follow the instructions in the attached newsletter article: Using Shuttle Radar Topography Mission (SRTM) Data in Surfer.
Updated February 8, 2017