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Author
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Topic: Exercise 5.7 problen #4
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KenO
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posted February 13, 2007 08:44 PM
Everything was going fairly swell until Box 5. (followed the directions on step 6 of page 5-11 in the book) rounded off the figure in Dec min box (to 41 from 41.4) which gave me a Hc of 54 41. Carrying that over to Box 6 gave me an a of 14.9. Seems that the answer in the back of the book carried over a dec min of 41.4 to get the correct answer of 14.5. So when to you round off and when do you not? The same thing occoured in problem 3 also where 59.8 rounded off to 60 gave me a dec min of 00.0 and the correct answer was 00.2. I can see that figure came from the 59.8. I am just trying to follow the directions as written.
Another problem with 5.7 #4, is how you get the lat of 37 45.5 in box 6. Your direction say to take the DS lat of box 1. round up and place in box 6. No where can I find any reference to lead me to figure out where you got the 45.5 nimber.
Referring back to previous problems (5.4), you always end up with a round number in the lat box in box 6 and the Hc is the number you get from pub 249 after rounding up the dec min figure.
I see where your answers came from, I just do not know how and why you got there.
Last question. What is the a lon in box 6? I got 15 24.4' Is that right?
Hope my questions make sense and you can help. If not let me know how to make my questions more clear.
Ken
From: Southern Oregon
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David Burch
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posted February 14, 2007 09:04 AM
I think part of your question is answered in earlier discussion. Please do a search on 5.7 to see the several places this problem is discussed.
For the Latitude answer, the one given is 14.5' (the a-value) south of (the Zn value is 180) of 38° N (the a-Lat).
For the Lon in box 6 question, which problem are you referring to?
Also, do a search on this discusion group on "interpolation." i have moved a topic here from our online course discussion that elaborates on the issue you raised, i believe. the topic is called "dec min interpolation" from about feb 2004
From: Starpath, Seattle, WA
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