Hello and good morning dear helmut,
many thanks for your kind and valuable answer.
My programs are in F90.
I used the subroutine circle to draw 2 circles perfectly from -90 to +90 degree with radius1 < radius2.
With xm and ym as being the centre of the circle, i was able to calculate the coordinates of the inner and outer circle and used a polygon filling routine in a second run, as suggested by you.
However, the results looks very weird. Only at the horizontal line ( 0 Degree) is a match, all other of my coordinates are far below the circles drawn by the subroutine circle.
Real, Parameter :: wd0=-90.
do i=0,179
wd=(wd0+float(i))
x1(i+1)=xm+(rad1*cos(wd))
y1(i+1)=ym+(rad1*sin(wd))
x2(i+1)=xm+(rad2*cos(wd))
y2(i+1)=ym+(rad2*sin(wd))
end do
Does the subroutine circle uses degree or polar coordinates ?
Best regards, Bapak Ireng