C      SUBROUTINE CIRCINIT (RR,A1,A2,DD, RP,ASTART,ADEL,NCH,YL,CLON)GC_TITLE  CIRCINIT  Calculates and Initializes arguments for CIRCUS.FOR.C_ARGUMENTS&	REAL RR      ![I] Radius in inches.  %	REAL A1      ![I] Arc start degrees.$	REAL A2      ![I] Arc stop degrees./	REAL DD      ![I] Allowed deviation in inches.>	REAL RP      ![O] Radius of a polar stereographic projection."	REAL ASTART  ![O] Starting angle.9	REAL ADEL    ![O] Delta increment for the arc increment.-	INTEGER*4 NCH  ![O] Number of output chords.	REAL YL      ![O]$	REAL CLON    ![O] Center longitude.C_VAR NONE.
C_DESCRIPTIONFC   Subroutine CIRCINIT initializes arguments for CIRCUS.FOR; it also HC   calculates the starting and ending angles from the input arguments, JC   the radius of a Polar Stereographic projection, the center longitude, 2C   and the delta increment for the arc increment.C_CALLS  MAPROJ#C_HISTORY  R.Gurule 87Jul14  USGS  C_END      REAL LLONA      COMMON /GRID/LLON,RLON,YLATMIN,YLATMAX,DLON,DLAT,KPROJ,IOPT      DATA LPT/1/,PI/3.1415927/      ADEL= PI / 360.0      NCH = 360$!-------CALCULATE CIRCUS ARGUMENTS.         TMPCLON = CLON        YLAT=YL        RAD= PI / 180.0.        CALL MAPROJ(LPT, TMPCLON,YLAT, XP, YP)J!--Calculate the hypotenuse of a triangle, this is the radius of our polar!  stereographic projection.	YP = SQRT(XP**2 + YP**2),        CALL MAPROJ(LPT,LLON,90.0,XPT1,YPT1),        CALL MAPROJ(LPT,LLON,YLAT,XPT2,YPT2),        CALL MAPROJ(LPT,RLON,YLAT,XPT3,YPT3)
        RR=YP        IF(YLAT.EQ.90)GO TO 900        XDEL= XPT3-XPT1        YDEL= YPT3-YPT1%        ASTART=   ATAN2D (YDEL,XDEL)         A2= (ASTART ) * RAD        XDEL1= (XPT2-XPT1)        YDEL1= (YPT2-YPT1))        A1= ATAN2D (YDEL1 , XDEL1)  * RAD 900    CONTINUE        RP = RR      RETURN	      END