The DM and DMS notations are the traditional standard for defining location. Folks who’ve grown up with the legacy notations find them simple and intuitive and often don’t realize they are using a base-60 number system invented by the ancient Babylonians to record fractional values. But the base-60 approach presents a learning challenge to geotech newbies and even perfectly formatted data can’t be plugged in to a computer as-is. The DD (Decimal Degree) notation, on the other hand, utilizes the base-10 number system we learned in grade school. People and computers appreciate not having to divide by 60 (or 3600) to know what is being said about location. These advantages have resulted in a strong push to make DD the universal standard. In our work, we use DD for logging new data and the first thing we do when we encounter DM or DMS data is convert it to DD. There are a gazillion ways to do the conversion. Setting it up as a set of formulas in Excel is nice because you can really see what’s going on.
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