A Calculator Program for Mixing Mercator and Great Circle Sailings

摘要

The Navigation Department, Defense Mapping Agency Hydrographic/Topographic Center (DMAHTC) has developed a calculator program, self-contained on one magnetic card, which automatically determines course, distance, and total run in Mercator and Great Circle Sailings. This program will list Great Circle positions every 10 deg of longitude and then print course and distance for each leg. Labels designating latitudes and longitudes, and program sections are also shown. The entire program is controlled by six label keys and can be shifted between Mercator and Great Circle at will. It is prepared on a programmable TI-59 with Marine Navigation Module software and printer capability. The program is in use at DMAHTC for compiling distance tables, and navigational publications and answering public inquiries. The following data are incorporated in this article: General Information, Mercator Computation, Great Circle Computation, Great Circle Positions, Great Circle Course Computation, Program Data, and Special Considerations. (Author)