3 = NGS Blue Book Format : NGS Blue Book format - *80* (Control Point) and *86* (Combo Height) Records. INTG uses information from the *80* and *86* records in Blue Book files. The Station Serial Number (SSN), the latitude and the longitude are read from the *80* records, the rest of the record is ignored. Only the *86* record is modified by INTG - the *80* records and all other records are passed through without change to the output file. Any *84* records are deleted. Information in columns 36-43 in the *86* record is created by INTG. For more information on this format, please refer to: 'Input Formats and Specifications of the National Geodetic Survey Data Base' 'Volume 1. Horizontal Control Data'. Published by the Federal Geodetic Control Committee in September 1994 and available from: the National Geodetic Survey, NOAA, Silver Spring, MD 20910. The following input example is *80* and *86* records from a Blue Book file: 004560*80*0096KNOXVILLE CT HSE 411906578 N0930548534 W 277 MIA33 004565*86*0096 any geoid values in here will be overwritten if ssn matches