Learning The Declination For An Area
Most use of declination is in conjunction with a map; as stated, that map may state (or even illustrate) the local declination. If not,
- A general isogonic chart of the world or continent can be consulted for a rough estimate of the local declination (within a few degrees)
- A prediction of the current magnetic declination for a given location (based on a worldwide empirical model of the deep flows described above) can also be obtained on-line from a web page operated by the National Geophysical Data Center, a division of the National Oceanic and Atmospheric Administration of the United States.
One would of course rather have the real declination than a prediction. However, a map is sure to be months or years out of date, whereas the model is built with all the information available to the map makers at the start of the five-year period it is prepared for. The model reflects a highly predictable rate of change, and will usually be more accurate than a map, and almost never less accurate.
Read more about this topic: Magnetic Declination
Famous quotes containing the words learning and/or area:
“I thought a minute, and says to myself, hold on,—s’pose you’d a done right and give Jim up; would you felt better than what you do now? No, says I, I’d feel bad—I’d feel just the same way I do now. Well, then, says I, what’s the use you learning to do right, when it’s troublesome to do right and ain’t no trouble to do wrong, and the wages is just the same?”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)
“Many women are reluctant to allow men to enter their domain. They don’t want men to acquire skills in what has traditionally been their area of competence and one of their main sources of self-esteem. So while they complain about the male’s unwillingness to share in domestic duties, they continually push the male out when he moves too confidently into what has previously been their exclusive world.”
—Bettina Arndt (20th century)