GEMPAK Projection Examples

13.0 GEMPAK Projection Examples

Map projections can be chosen based on the desired map properties. For example:

Orthographic projection is used to repesent the Earth as viewed from infinity.
GAREA = 0;-105;0;-105
PROJ = ort/50;-105;0

The cylindrical projection can be rotated to view both poles at the same time.
GAREA = 0;0;0;0
PROJ = ced/0;-105;45

Any straight line drawn on a Gnomic map is on a great circle, and can be used to find the shortest path between two points. Gnomic is often useful for ocean and seismic waves which tend to travel along great circles.
GAREA = -10;145;60;-80
PROJ = gno/21;-157;0

GEMPAK Online Tutorial > GEMPAK Projections

Orthographic projection is used to repesent the Earth as viewed from infinity. GAREA = 0;-105;0;-105 PROJ = ort/50;-105;0
The cylindrical projection can be rotated to view both poles at the same time. GAREA = 0;0;0;0 PROJ = ced/0;-105;45
Any straight line drawn on a Gnomic map is on a great circle, and can be used to find the shortest path between two points. Gnomic is often useful for ocean and seismic waves which tend to travel along great circles. GAREA = -10;145;60;-80 PROJ = gno/21;-157;0