Chart question

[ibcd]

Please help me solve this question. GSP Navigation, Chap 8

Q 8: On a transverse Mercator based on the 40E Meridian, the scale error at 80N 130E would be:

a) 1.5% too small
b) 1.5% too large
c) 0.985
d) 1.015

The correct answer give in (b), but I have no clue how to get to it.

Thanks

[LH2]

Something's wrong there. If it's a Transverse Mercator with a prime meridian of 40E, the scale 90 degrees off at 130E is infinity [1/cos(130-40) = 1/cos(90) = 1/0].

Also, assuming a reference scale of 1.0000, answers a & c, and b & d are one and the same.

Can you check you haven't made a transcription error in your post?

[EK4457]

Yup. I think you'll find the question will be refering to 30E, not 130E.

Then: 1 / cos(40-30) = 1 / cos10 = 1.015

And then you get the question wrong because it asks for the ERORR. If the original scale was 1.00 (and correct) and your new scale is 1.015, then it has increase by 0.015 (the error). Which, of course, is 1.5%.

Answer (b).

EK

[ibcd]

Thanks for the help. The book does say 130E, but I believe that's a print error, after your inputs.

Thanks...