830 
procedure prtline(var f : text; slope : integer); 
var 
j : integer; 
begin 
write(f, slope:2, '); 
for j : = 90 to 359 do 
if j mod 5=0 then 
begin 
write(f, buf[j]); 
end; 
for j := 0 to 89 do 
if j mod 5=0 then 
begin 
write(f, buf[j]); 
end; 
writeln(f); 
end ; 
procedure prtlegend ; 
begin 
writeln ('s = shadow; * = shadow, not visible'); 
writeln ('. = sunlit, visible; i = sunlit, not visible') 
end; 
function iglo(alfa, phi : real) : real; 
begin 
if phi >= alfa then 
iglo := 0 
else 
iglo := acosd(tand(phi)/tand(alfa)) 
end ; 
procedure readin; 
begin 
writeln('This is program Iglospot to show areas of shadow and'); 
writeln('of (steep) slope invisibility in sidelook SPOT imagery'); 
write('Enter sun elevation: (0-90) '); readln(sunang); 
write('Enter sun azimuth: '); readln(sundir); 
write('Enter incidence angle: (0-27) '); readln(lookang); 
write('Lookdirection left or right: (1/r) '); readln(lr); 
write('Satellite inclination: (98.7) '); readln(lookdir); 
sundir := sundir + 180; 
if sundir > 360 then 
sundir :» sundir - 360; 
sunang :» 90 - sunang; 
if lr in [ ' r' , 'R' ] then 
lookdir := lookdir + 180; 
end;