Polar Grids Q
Thread Starter
Join Date: Apr 2000
Location: West Midlands, UK.
Age: 73
Posts: 294
Likes: 0
Received 0 Likes
on
0 Posts
Polar Grids Q
Would appreciate some guidance with the solution of this Q. I have not included values as the Q is from an FTO and may be copyright.
A Northern L.C.C is overprinted with false grid. Constant of cone of chart is A.
At B degrees West the grid track is C and the true track D.
At which longitude is the false grid aligned?
Thanks
A Northern L.C.C is overprinted with false grid. Constant of cone of chart is A.
At B degrees West the grid track is C and the true track D.
At which longitude is the false grid aligned?
Thanks
Join Date: Feb 2002
Location: oxford
Posts: 247
Likes: 0
Received 0 Likes
on
0 Posts
Comparing C and D will give you the chart convergence, and also whether E or W.
On a Lamberts chart, convergence = change of longitude (from the datum) x sin of parallel of origin (or 'n' factor).
Therefore, change of longitude = chart convergence/'n'
That change of longitude is the difference between B and the datum.
You now have to work out which sense to apply it . In the N hemisphere, if convergence is W, B is E of the datum. In the S hemisphere, if convergence is W, B is W of the datum.
Can't you ask the instructors at your FTO?
On a Lamberts chart, convergence = change of longitude (from the datum) x sin of parallel of origin (or 'n' factor).
Therefore, change of longitude = chart convergence/'n'
That change of longitude is the difference between B and the datum.
You now have to work out which sense to apply it . In the N hemisphere, if convergence is W, B is E of the datum. In the S hemisphere, if convergence is W, B is W of the datum.
Can't you ask the instructors at your FTO?
