GNAV Charts

Lambert: Great Circle

Straight line, but actually curve concave to PoO

Polar: Great Circle

Can be taken as straight line, but is actually curve concave to the pole

Mercator: Great Circle:

Curve convave to equator

Lambert: Rhumb Line

Curves concave to the pole. Is below the GC. (NH)

Polar: Rhumb Line

Curve concave to nearest pole

Mercator Rhumb Line

Straight line

Lambert Convergency

Ch Long x sin(PoO)

CoC = sin(PoO)

Polar Convegency

ch long

Mercator Convergency

ch long x sin(mean lat)

Lambert Scale:

Between SP - Scale Contract (1cm = more earth distance)

Outside the scale expands

Scale is correct at SP.

Polar Scale

Assume scale constant, but actually expands away from pole

Mercator Scale

Only correct at Equator, expands away from it. (1cm = less earth distance)