DCL:GRPH1:STPACK: Transformation Functions:Explanation of Subroutines: Coordinate Transformation (Subroutines)
Performs a normalization transformation (transformation of UC and VC) or map projection (transformation of TC and VC).
vx, vy = NumRu::DCL.stftrn(ux,uy)
ux, uy = NumRu::DCL.stitrn(vx,vy)
ux,uy (R) The coordinates of UC/TC vx,vy (R) The coordinates of VC. itr (I) Transformation function number cxa,cya (R) Factor to multiply coordinate value by vx0,vy0 (R) The position of the origin in VC
- In a map projection, if transformation is impossible due to factors such as singular points, the value of the internal variable rundef managed by glpget/glpset is returned. (The initial value is -999.0.)
- This function performs the following operations.
- Performs a basic transformation on (UX,UY) to (XX,YY) according to the transformation function number
- Furthermore, it expands or shifts byvx = cxa*xx + vx0
vy = cya*xx + vy0