Navigation: Where Am I?
[caption id="attachment_3227" align="alignright" width="380"] Navigation in the 1700's.[/caption] When people started traveling, it was imperative to be able to answer the question: where am I? This is not such a problem with land navigation because there are lots of landmarks to guide the traveler. Early, the Portuguese sailors used sets of directions they called rutters. A rutter might say, “Sail directly west from Sagres until you see a small Island. If you arrive there after October 30, wait until April 1 to proceed north or you will never make it…”. The Portuguese kept their rutters out of foreign hands. The invention of latitude and longitude to map the earth made the rutters obsolete. But how do you know the latitude and longitude of your present position? Latitude is One Thing…