| MapDataReader |
The map data file is a big array of short (16-bit) ints, as follows: - it is
a sequence of closed curves - the first value in a curve is the number of
points in the curve - the second value in a curve indicates land/water (1 or
-1, respectively) - this is followed by an [x,y,z] triple that indicates a
point on the unit sphere (each of x, y, and z has been scaled by 30000),
where the x axis points "to the right" (towards 0 N 90 E), the y axis points
"up" (towards the north pole), and the z axis points "out of the screen"
(towards 0 N 0 E). this is the starting point of the curve. - this is
followed by (one less than the number of points in the curve) triples
[dx,dy,dz]; the [x,y,z] triple for each successive point in the curve is
obtained by adding [dx,dy,dz] onto the previous [x,y,z] values. - the curves
are [must be!] |