Calculations

Question 1

Arc to time calculation

Answer 1

(longitude×4)/60 .

Equivalent to LONGITUDE/15

Question 2

Departure formula

Answer 2

∆LONG (MINUTES) ×COS LAT

Question 3

Convergency formula

Answer 3

∆Long (degrees) x sin (mean LAT)

∆ Longitude= change in longitude between the two points.
Mean LAT= average of two latitude, eg (45+55)/2= 50

Question 4

Conversion angle

Answer 4

1/2×∆Longitude (degrees) × SIN (mean LAT)

Question 5

Scale correct at? -Lambert conformal

Answer 5

Standard of parallel.

Ie. Where a parallel board touches tangent to earth surface for conformal projection.

Question 5

Scale correct at? -Lambert conformal

Answer 5

Standard of parallel.

Ie. Where a parallel board touches tangent to earth surface for conformal projection.

Question 6

Formula CHART convergency

Answer 6

Chart convergency = ∆Long × sin(parallel of origin)

Different to earth convergency!! Sin(mean LAT)

Question 7

Earth convergency correct at:

Answer 7

Lambert chart- parallel of origin.

Question 8

Where is scale correct on mercator chart?

Answer 8

Only at the EQUATOR

Question 9

Are great circle track closer or further to poles than Parallels of Latitude?

Answer 9

Closer. Great circles convex towards POLES

Question 10

Chart convergency formula

Answer 10

∆Long× sin Parallel of Origin.

Or if given statement chart=earth convergency, use convergency formula