# DIRDIS - FIND SHORTEST DIRECTION AND DISTANCE BETWEEN TWO
#	   POINTS IN A UNIV W/ WRAP-AROUND	# GSW  2/28/82
SUBROUTINE DIRDIS( X0, Y0, X1, Y1, DIR, DIS )
REAL  X0, Y0, X1, Y1	#INPUT - POINTS CO-ORDS, 1.0 TO 101.0
REAL  DIR		#OUTPUT- DIRECTION (X0,Y0) TO (X1,X1), 0-360
REAL  DIS		#OUTPUT- DISTANCE BETWEEN POINTS

DEFINE(DEGRAD,57.29577951)	#DEGREES PER RADIAN CONVERSION

XC = X1
DX = ABS( X0 - X1 )
IF ( DX > 50. ) [
  DX = 100. - DX
  IF ( X1 < 51. )
    XC = XC + 100.
  ELSE 
    XC = XC - 100.
  ]

YC = Y1
DY = ABS( Y0 - Y1 )
IF ( DY > 50. ) [
  DY = 100. - DY
  IF ( YC < 51.) 
    YC = YC + 100.
  ELSE 
    YC = YC - 100.
  ]

DIS = SQRT( DX*DX + DY*DY )

DIR = ATAN3( YC-Y0, XC-X0 ) * DEGRAD
IF ( DIR .LT. 0 ) DIR = DIR + 360.

RETURN
END
# DSTNCE - FIND SHORTEST DISTANCE BETWEEN TWO
#	   POINTS IN A UNIV W/ WRAP-AROUND	# GSW  2/28/82
REAL FUNCTION DSTNCE( X0, Y0, X1, Y1, DIR, DIS )
REAL  X0, Y0, X1, Y1	#INPUT - POINTS CO-ORDS, 1.0 TO 101.0
REAL  DIS		#OUTPUT- DISTANCE BETWEEN POINTS

XC = X1
DX = ABS( X0 - X1 )
IF ( DX > 50. ) [
  DX = 100. - DX
  IF ( X1 < 51. )
    XC = XC + 100.
  ELSE 
    XC = XC - 100.
  ]

YC = Y1
DY = ABS( Y0 - Y1 )
IF ( DY > 50. ) [
  DY = 100. - DY
  IF ( YC < 51.) 
    YC = YC + 100.
  ELSE 
    YC = YC - 100.
  ]

DSTNCE = SQRT( DX*DX + DY*DY )

RETURN
END