File indexing completed on 2025-01-12 06:34:50

 ' Goode Homolosine - Interrupted for Continents

 ' Central longitude of map (Lambda0) = 0 Degrees

 '

 ' ===================================

 '

 '  Program Written by:

 '    Paul B. Anderson (804) 853-7595

 '    3214 Chalfin Ave.

 '    Norfolk, Va. 23513

 '

 ' ===================================

 '

 ' Main Map Formula From "AN ALBUM OF MAP PROJECTIONS"

 '                        by John P. Snyder & Philip M. Voxland, 1987.

 '                        (U.S. Geological Survey Professional Paper 1453)

 '

 ' Function MollweideFormula# (Used in Mollweide Iteration) is from:

 '                       "MAP PROJECTIONS -- A WORKING MANUAL"

 '                        by John P. Snyder, 1987.

 '                        (U.S. Geological Survey Professional Paper 1395)

 '

 ' ==============

 '  Declarations

 ' ==============

 '

 DECLARE SUB Alert ()
 DECLARE SUB CRTColorMenu ()
 DECLARE SUB DataPointsMenu ()
 DECLARE SUB DrawGrid ()
 DECLARE SUB DrawOutline ()
 DECLARE SUB DrawProjection (PolyLine%)
 DECLARE SUB FeaturesMenu ()
 DECLARE SUB GetMapData (FileName$)
 DECLARE SUB Goode (DeltaLambda#, Radius#, XCoord#, YCoord#)
 DECLARE SUB LatLongEntry (Title$, Note$)
 DECLARE SUB LatLongMenu ()
 DECLARE SUB LongitudeFOR (Begin#, Finish#, Incr#)
 DECLARE SUB MakeLatitudeLines (LatRange%, LatDetail%)
 DECLARE SUB MakeLongitudeLines (LatRange%, LongDetail!)
 DECLARE SUB PlotFileColorMenu ()
 DECLARE SUB ReadInfile (Byte%)
 DECLARE FUNCTION ArcCos# (n#)
 DECLARE FUNCTION ArcSin# (n#)
 DECLARE FUNCTION ArcTanH# (n#)
 DECLARE FUNCTION Atan2# (b#, a#)
 DECLARE FUNCTION Center% (Length%)
 DECLARE FUNCTION ConvertCoordToDecDeg# (coord#)
 DECLARE FUNCTION CoTan# (n#)
 DECLARE FUNCTION LN# (n#)
 DECLARE FUNCTION MollweideFormula# (ThetaPrime#, MPhi#)
 DECLARE FUNCTION Normalize# (LambdaVal#, Lambda0Val#)
 DECLARE FUNCTION PointCount& (PtCnt&)
 DECLARE FUNCTION PolyLineColor% (PolyLineHeader%)
 DECLARE FUNCTION Raise# (n#, Power#)
 DECLARE FUNCTION Round# (n#, PowerOfTen%)
 DECLARE FUNCTION Sec# (n#)
 DECLARE FUNCTION Sign# (n#)
 '

 ' ===========

 '  Constants

 ' ===========

 '

 CONST FALSE = 0
 CONST TRUE = NOT FALSE
 CONST SQRT2 = 1.414213562373095#             ' SQR(2)

 CONST DEG180 = 3.1415926535898#              ' PI

 CONST DEG90 = 1.5707963267949#               ' PI / 2

 CONST DEG360 = 6.2831853071796#              ' PI * 2

 CONST DEG45 = .7853981633974501#             ' PI / 4

 CONST RAD2DEG = 57.29577951308219#           ' 180 / PI

 CONST DEG2RAD = 1.745329251994333D-02        ' PI / 180

 CONST MIN2RAD = 2.908882086657222D-04        ' DEG2RAD / 60

 CONST MERGEPOINT = .710988432654746#         ' 40.73666 * DEG2RAD

 CONST TOLERANCE = .0000001# ' Tolerance value for Newton-Raphson routine

 CONST DTPINCR = .00001# ' Increment value for Delta Theta Prime

 '                          (inside Newton-Raphson routine)

 '

 ' additional Degree Values used in this projection

 ' Put Here to avoid repetitive calculation

 '

 CONST DEG10 = 10 * DEG2RAD
 CONST DEG20 = 20 * DEG2RAD
 CONST DEG30 = 30 * DEG2RAD
 CONST DEG40 = 40 * DEG2RAD
 CONST DEG50 = 50 * DEG2RAD
 CONST DEG60 = 60 * DEG2RAD
 CONST DEG80 = 80 * DEG2RAD
 CONST DEG100 = 100 * DEG2RAD
 CONST DEG140 = 140 * DEG2RAD
 CONST DEG160 = 160 * DEG2RAD
 
 CONST XCONST = .9003163161571041#            ' (8# ^ .5#) / Deg180#

 CONST MOLLRFACTOR = .0528#                   ' Reduction factor applied to

 '                                              Mollweide to match parallels

 '                                              of sinusoidal portion of

 '                                              the projection

 '

 CONST XCENTER = 320           ' VGA Center X

 CONST YCENTER = 240           ' VGA Center Y

 CONST ASPECT = 1              ' VGA mode 12 -- 640x480 aspect ratio = 1

 CONST CRTRADIUS = 100         ' Radius Value for CRT display

 CONST PLOTRADIUS = 1          ' Radius Value for Plot File

 CONST PLTXCENTER = 5588       ' (25.4 * 5.5#) / .025

 CONST PLTYCENTER = 4318       ' (25.4 * 4.25#) / .025

 CONST LAMBDA0 = 0             ' Central Longitude of map for Goode

 '                                 Homolosine Interrupted for Continental

 '                                 Lobes.

 '

 ' ============================

 ' TYPE Definition For PNT file

 ' ============================

 '

 TYPE PNTRecord
   Header AS INTEGER
   Lat AS INTEGER
   Lon AS INTEGER
 END TYPE
 '

 DIM SHARED PNTData AS PNTRecord
 '

 ' =========================================

 ' Type Definition for Global Variables (G.)

 ' =========================================

 '

 TYPE GlobalVariables
   CrtX AS DOUBLE             ' Intermediate value for X Coordinate

   CrtY AS DOUBLE             ' Intermediate value for Y Coordinate

   ModCrtX AS DOUBLE          ' Modified to be centered on CRT

   ModCrtY AS DOUBLE          ' Modified to be centered on CRT

   LastModCrtX AS DOUBLE
   LastModCrtY AS DOUBLE
   LastCrtY AS DOUBLE
   Lambda AS DOUBLE           ' Longitude in Radians

   Lambda2 AS DOUBLE          ' Central Longitude of Lobe

   Phi AS DOUBLE              ' Latitude in Radians

   Visible AS INTEGER         ' When True --> Draw PolyLine%

   Grid AS INTEGER            ' When True --> Draw Grid

   Outline AS INTEGER         ' When True --> Skip Lobe IF-Then statements

   MapDataLevel AS INTEGER    ' Levels 1 to 5

   ExtensionLobe1 AS INTEGER  ' When True --> Draw extension 1

   ExtensionsLobe2 AS INTEGER ' When True --> Draw extensions 2 & 3

   ColorVal AS INTEGER        ' CRT Color Out

   GridColor AS INTEGER       ' CRT Color for Grid

   CoastColor AS INTEGER      ' CRT Color for Coasts

   BorderColor AS INTEGER     ' CRT Color for Political Borders

   IslandColor AS INTEGER     ' CRT Color for Islands

   StateColor AS INTEGER      ' CRT Color U.S. State borders

   LakeColor AS INTEGER       ' CRT Color for Lakes

   RiverColor AS INTEGER      ' CRT Color for Rivers

   ProvinceColor AS INTEGER   ' CRT Color for Canadian Provinces

   AustColor AS INTEGER       ' CRT Color for Australian States

   MexicoColor AS INTEGER     ' CRT Color for Mexican States

   GridPen AS INTEGER         ' Grid color for Plot File

   CoastPen AS INTEGER        ' Coast color for Plot File

   BorderPen AS INTEGER       ' Border color for Plot File

   IslandPen AS INTEGER       ' Island color for Plot File

   StatePen AS INTEGER        ' State color for Plot File

   LakePen AS INTEGER         ' Lake color for Plot File

   RiverPen AS INTEGER        ' River color for Plot File

   ProvincePen AS INTEGER     ' Canadian Province color for Plot File

   AustPen AS INTEGER         ' Australian State color for Plot File

   MexicoPen AS INTEGER       ' Mexican State color for Plot File

   LastPlotPen AS STRING * 1  '

   PlotFile AS INTEGER        ' When True Plot to a File

   CoastSW AS INTEGER         ' When True Plot to Crt or file

   BorderSW AS INTEGER        ' When True Plot to Crt or file

   IslandSW AS INTEGER        ' When True Plot to Crt or file

   StateSW AS INTEGER         ' When True Plot to Crt or file

   LakeSW AS INTEGER          ' When True Plot to Crt or file

   RiverSW AS INTEGER         ' When True Plot to Crt or file

   ProvinceSW AS INTEGER      ' When True Plot to Crt or file

   AustSW AS INTEGER          ' When True Plot to Crt or file

   MexicoSW AS INTEGER        ' When True Plot to Crt or file

   LongStep AS INTEGER        ' Grid Longitude Increment

   LatStep AS DOUBLE          ' Grid Latitude Increment

   LongOption AS INTEGER      ' 1 - Longitude to pole, 2 - ends at +/-85 deg.

 END TYPE
 
 DIM SHARED G AS GlobalVariables
 '

 ' > variables used by GetPKDData example routines

 '

 ' for the *.PKD file format

 ' DIM SHARED Index AS DOUBLE

 ' DIM SHARED PointsInLine AS LONG

 ' DIM SHARED LonI AS DOUBLE

 ' DIM SHARED LatI AS DOUBLE

 ' DIM SHARED LonR AS DOUBLE

 ' DIM SHARED LatR AS DOUBLE

 ' DIM SHARED FeatureType AS INTEGER

 ' DIM SHARED LoopCount AS LONG

 ' DIM SHARED Infile$(23)

  
 '

 ' =========================

 '  Program starting values

 ' =========================

 '

 ' > Flags to tell the program when to draw the map inside the extensions

 '

 G.ExtensionLobe1 = FALSE
 G.ExtensionsLobe2 = FALSE
 '

 ' > Starting CRT colors for Geographical features

 '

 G.GridColor = 0       ' Black

 G.CoastColor = 0      ' Black

 G.BorderColor = 4     ' Red

 G.IslandColor = 0     ' Black

 G.StateColor = 4      ' Red

 G.LakeColor = 1       ' Blue

 G.RiverColor = 1      ' Blue

 '

 ' > Note: Color values for the following actually use U.S. State color

 '         they are not hooked into the CRT color menu

 '

 G.ProvinceColor = 4   ' Red

 G.AustColor = 4       ' Red

 G.MexicoColor = 4     ' Red

 '

 ' > Starting Plot File colors for Geographical features (Used by Corel Draw)

 '

 G.GridPen = 1         ' Black

 G.CoastPen = 1        ' Black

 G.BorderPen = 3       ' Red

 G.IslandPen = 1       ' Black

 G.StatePen = 3        ' Red

 G.LakePen = 2         ' Blue

 G.RiverPen = 2        ' Blue

 '

 ' > Note: Color values for the following actually use U.S. State color

 '         they are not hooked into the Pen color menu

 '

 G.ProvincePen = 3     ' Red

 G.AustPen = 3         ' Red

 G.MexicoPen = 3       ' Red

 '

 ' > Starting Geographical Features (All ON)

 '

 G.CoastSW = TRUE
 G.BorderSW = TRUE
 G.IslandSW = TRUE
 G.StateSW = TRUE
 G.LakeSW = TRUE
 G.RiverSW = TRUE
 G.ProvinceSW = TRUE
 G.AustSW = TRUE
 G.MexicoSW = TRUE
 '

 ' > Starting Latitude and longitude increment -- Traditional View

 '

 G.LongStep = 10#
 G.LatStep = 10#
 G.LongOption = 2
 '

 ' > Starting Database level

 '

 G.MapDataLevel = 3
 '

 ' > Plotting Variables, Plot Size = A

 '

 G.PlotFile = TRUE
 Plotpass% = 0 'WARNING:  Will not write over existing file while in program.

 '

 '                       --------------- HOWEVER -------------------

 '                       IF you EXIT the program and then restart it

 '                       It WILL write over existing Plot files!!!!!

 '                       -------------------------------------------

 '

 UserQuits% = FALSE  ' Don't Quit yet

 
 VIEW PRINT 1 TO 25
 '

 ' { Main Program }

 '

 DO
   MenuItem% = 0 ' No Menu Items Selected

   COLOR 7, 9
   CLS
 '

   LOCATE 2, 29: PRINT "======================="
   LOCATE 3, 30: PRINT "W O R L D   V I E W S"
   LOCATE 4, 29: PRINT "======================="
   LOCATE 6, 24: PRINT "Map Projection Library, Volume 1"
   LOCATE 8, 24: PRINT " 1. Draw"
   LOCATE 16, 30: PRINT "World Views' Options"
   LOCATE 18, 12: PRINT " 2. Change CRT Color of Geographical Features"
   LOCATE 19, 12: PRINT " 3. Turn Geographical Features On/Off "
   LOCATE 20, 12: PRINT " 4. Modify Latitude/Longitude Display"
   LOCATE 21, 12: PRINT " 5. Increase/Decrease Amount of Points to Plot"
   LOCATE 22, 12: PRINT " 6. Change Plot File Pen Colors of Geographical Features"
   LOCATE 24, 21
   INPUT "Select Menu Item (1-6) or 0 to Quit: ", MenuItem%
 '

   SELECT CASE MenuItem%
 '

     CASE 0
       UserQuits% = TRUE
 
     CASE 1
     ' Draw the Map

       Title$ = " Goode Homolosine Projection "
       Note$ = "Central Longitude of Map is 0 Degrees"
       CALL LatLongEntry(Title$, Note$)
 '

       IF G.PlotFile THEN
         Plotpass% = Plotpass% + 1
         PlotFile$ = "C:\WV\WVPLOT" + LTRIM$(STR$(Plotpass%)) + ".PLT"
         OPEN PlotFile$ FOR OUTPUT AS #1
         PRINT #1, "IN; IP0,0,11176,8636; SP0;"
         PRINT #1, "SC-5498,5498,-4249,4249;"
         PRINT #1, "VS4; PT 0.1; SP1;"
         G.LastPlotPen = "1"
       END IF
 
       SCREEN 12 ' Switch to VGA 480/640, 16 COLOR mode

       VIEW (0, 0)-(639, 479), 7
 '

       COLOR 10
       Col% = Center%(LEN(Title$))
       LOCATE 1, Col%: PRINT Title$;
 
       CALL DrawOutline
  
 '     CALL GetPKDData

  
       IF G.Grid THEN CALL DrawGrid
       IF G.CoastSW THEN CALL GetMapData("PCoast.pnt")
       IF G.IslandSW THEN CALL GetMapData("PIsland.pnt")
       IF G.LakeSW THEN CALL GetMapData("Plake.pnt")
       IF G.RiverSW THEN CALL GetMapData("River.pnt")
       IF G.BorderSW THEN CALL GetMapData("PBorder.pnt")
       IF G.StateSW THEN CALL GetMapData("PUSA48.pnt")
       IF G.ProvinceSW THEN CALL GetMapData("PCanProv.pnt")
       IF G.AustSW THEN CALL GetMapData("PAust.pnt")
       IF G.MexicoSW THEN CALL GetMapData("PMexico.pnt")
 
       G.ExtensionLobe1 = TRUE
       IF G.CoastSW THEN CALL GetMapData("PCoast.pnt")
       IF G.IslandSW THEN CALL GetMapData("PIsland.pnt")
 
       G.ExtensionLobe1 = FALSE
       G.ExtensionsLobe2 = TRUE
  
       IF G.CoastSW THEN CALL GetMapData("PCoast.pnt")
       IF G.IslandSW THEN CALL GetMapData("PIsland.pnt")
  
       G.ExtensionsLobe2 = FALSE
  
       IF G.PlotFile THEN
         PRINT #1, "PU 0,0; SP00;"
         CLOSE #1
       END IF
 
       CALL Alert ' BEEP

  
       COLOR 12
       LOCATE 1, Col%: PRINT Title$;
     
       DO
         Brk$ = INKEY$
       LOOP UNTIL Brk$ > ""
    
       SCREEN 0  'Switch back to Text mode

       VIEW PRINT 1 TO 25
    
     CASE 2
     ' Change Line Color of Geographical features

       CALL CRTColorMenu
         
     CASE 3
     ' Turn Geographical features OFF or ON

       CALL FeaturesMenu
 '

     CASE 4
     ' Change Latitude and Longitude Values

       CALL LatLongMenu
 '

     CASE 5
     ' Change the Amount of Database Latitude and Longitude Values to plot

       CALL DataPointsMenu
 '

     CASE 6
     ' Change the Line color of the Geographical features sent to the plot file

       CALL PlotFileColorMenu
 '

     CASE ELSE
       PRINT CHR$(7);
 
   END SELECT '{ MenuItem. }

 '

 LOOP UNTIL UserQuits%
 '

 END
 
 SUB Alert
 ' { Sounds a tone when map is complete. }

 
   SOUND 880, 36.4
 
 END SUB ' { Alert. }

 
 FUNCTION ArcCos# (n#) STATIC
 '

 IF n# <> 0 THEN
   ArcCos# = ATN(Raise#(1 - (n# * n#), .5) / n#) + DEG180 * (n# - ABS(n#)) / (2 * n#)
 ELSE
   n# = 0
 END IF
 '

 END FUNCTION '{ ArcCos#. }

 
 FUNCTION ArcSin# (n#) STATIC
 '

   IF ABS(n#) < 1 THEN
     ArcSin# = ATN(n# / Raise#(1 - (n# * n#), .5))
     EXIT FUNCTION
   END IF
 
   IF n# = 1 THEN
     ArcSin# = DEG90
     EXIT FUNCTION
   END IF
 
   IF n# = -1 THEN
     ArcSin# = -DEG90
   END IF
 '

 END FUNCTION ' { ArcSin#. }

 
 FUNCTION ArcTanH# (n#) STATIC
 '

     AT1# = ABS(n#)
 '

     IF AT1# < 1 THEN
       AT2# = .5 * LN#((1 + AT1#) / (1 - AT1#))
       ArcTanH# = AT2# * Sign#(n#)
     END IF
 '

 END FUNCTION ' { ArcTanH#.}

 
 FUNCTION Atan2# (b#, a#)
 '

 IF a# = 0 THEN
   IF b# > 0 THEN
     Atan2# = DEG90
   ELSEIF b# < 0 THEN
     Atan2# = -DEG90
   ELSE
     Atan2# = 0
   END IF
 '

 ELSEIF b# = 0 THEN
   IF a# < 0 THEN
     Atan2# = DEG180
   ELSE
     Atan2# = 0
   END IF
 '

 ELSE
   IF a# < 0 THEN
     IF b# > 0 THEN
       Atan2# = ATN(b# / a#) + DEG180
     ELSE
       Atan2# = ATN(b# / a#) - DEG180
     END IF
 '

   ELSE
     Atan2# = ATN(b# / a#)
   END IF
 END IF
 '

 END FUNCTION '{ ATan2#. }

 
 FUNCTION Center% (Length%)
 '

     IF Length% MOD 2 = 0 THEN
       Column% = 40 - (Length% \ 2)
     ELSE
       Column% = (40 - (Length% \ 2)) + 1
     END IF
 '

     Center% = Column%
 '

 END FUNCTION '{ Center$. }

 
 FUNCTION ConvertCoordToDecDeg# (coord#)
 ' Used by GetPKDData subroutine

 '

   ConvertCoordToDecDeg# = coord# / 3600
 '

 END FUNCTION '{ ConvertCoordToDecDeg#. }

 
 FUNCTION CoTan# (n#)
 '

   Sine# = SIN(n#)
   IF ABS(Sine#) <= .0001 THEN
     PRINT "Error: CoTan#(n#) Where n# <= 0"
     SYSTEM
   ELSE
     CoTan# = COS(n#) / Sine#
   END IF
 '

 END FUNCTION '{ CoTan#. }

 
 SUB CRTColorMenu
 '

 ExitMenu% = FALSE
 '

 DO
   CLS
   LOCATE 2, 18: PRINT "** Change CRT Color of Geographical Features **"
   LOCATE 4, 36: PRINT "Color Codes"
   LOCATE 5, 22: PRINT "0 - Black"
   LOCATE 6, 22: PRINT "1 - Blue    6 - Brown      11 - Lt. Cyan "
   LOCATE 7, 22: PRINT "2 - Green   7 - White      12 - Lt. Red  "
   LOCATE 8, 22: PRINT "3 - Cyan    8 - Dk. Grey   13 - Lt. Magenta"
   LOCATE 9, 22: PRINT "4 - Red     9 - Lt. Blue   14 - Yellow"
   LOCATE 10, 22: PRINT "5 - Magenta 10 - Lt. Green 15 - Br. White"
   LOCATE 12, 28: PRINT "1. Grid Color is:"; G.GridColor
   LOCATE 13, 28: PRINT "2. Coast Color is:"; G.CoastColor
   LOCATE 14, 28: PRINT "3. Border Color is:"; G.BorderColor
   LOCATE 15, 28: PRINT "4. Island Color is:"; G.IslandColor
   LOCATE 16, 28: PRINT "5. State Border Color is:"; G.StateColor
   LOCATE 17, 28: PRINT "6. Lake Color is:"; G.LakeColor
   LOCATE 18, 28: PRINT "7. River Color is:"; G.RiverColor
   LOCATE 20, 14
   INPUT "Select Option (1-7) or 0 to Return to Main Menu: ", Menu%
      
   SELECT CASE Menu%
 '

     CASE 0
       ExitMenu% = TRUE
 '

     CASE 1
       LOCATE 20, 1: PRINT SPACE$(80)
       LOCATE 20, 14
       INPUT "Change Grid Color to (0-15):", NewColor%
 '

       IF NewColor% >= 0 AND NewColor% < 16 THEN
         G.GridColor = NewColor%
       ELSE
         PRINT CHR$(7)
       END IF
 '

     CASE 2
       LOCATE 20, 1: PRINT SPACE$(80)
       LOCATE 20, 14
       INPUT "Change Coastline Color to (0-15):", NewColor%
 '

       IF NewColor% >= 0 AND NewColor% < 16 THEN
         G.CoastColor = NewColor%
       ELSE
         PRINT CHR$(7)
       END IF
 '

     CASE 3
       LOCATE 20, 1: PRINT SPACE$(80)
       LOCATE 20, 14
       INPUT "Change Border Color to (0-15):", NewColor%
 '

       IF NewColor% >= 0 AND NewColor% < 16 THEN
         G.BorderColor = NewColor%
       ELSE
         PRINT CHR$(7)
       END IF
 '

     CASE 4
       LOCATE 20, 1: PRINT SPACE$(80)
       LOCATE 20, 14
       INPUT "Change Island Color to (0-15):", NewColor%
 '

       IF NewColor% >= 0 AND NewColor% < 16 THEN
         G.IslandColor = NewColor%
       ELSE
         PRINT CHR$(7)
       END IF
 '

     CASE 5
       LOCATE 20, 1: PRINT SPACE$(80)
       LOCATE 20, 14
       INPUT "Change State Border Color to (0-15):", NewColor%
 '

       IF NewColor% >= 0 AND NewColor% < 16 THEN
         G.StateColor = NewColor%
       ELSE
         PRINT CHR$(7)
       END IF
 '

     CASE 6
       LOCATE 20, 1: PRINT SPACE$(80)
       LOCATE 20, 14
       INPUT "Change Lake Color to (0-15):", NewColor%
 '

       IF NewColor% >= 0 AND NewColor% < 16 THEN
         G.LakeColor = NewColor%
       ELSE
         PRINT CHR$(7)
       END IF
 '

     CASE 7
       LOCATE 20, 1: PRINT SPACE$(80)
       LOCATE 20, 14
       INPUT "Change River Color to (0-15):", NewColor%
 '

       IF NewColor% >= 0 AND NewColor% < 16 THEN
         G.RiverColor = NewColor%
       ELSE
         PRINT CHR$(7)
       END IF
 '

     CASE ELSE
       PRINT CHR$(7)
 '

     END SELECT '{ Menu. }

 '

   LOOP UNTIL ExitMenu%
 '

 END SUB ' { CRTColor. }

 
 SUB DataPointsMenu
 '

 ExitMenu% = FALSE
 '

 DO
   CLS
 '

   LOCATE 2, 16: PRINT "** Increase/Decrease Amount of Points to Plot **"
   LOCATE 4, 27: PRINT "Current Database Level is"; G.MapDataLevel
   LOCATE 6, 25: PRINT "1. 179,331 X-Y Coordinate Pairs"
   LOCATE 7, 25: PRINT "2. 109,992 X-Y Coordinate Pairs"
   LOCATE 8, 25: PRINT "3. 27,393 X-Y Coordinate Pairs"
   LOCATE 9, 25: PRINT "4. 14,867 X-Y Coordinate Pairs"
   LOCATE 10, 25: PRINT "5. 5,365 X-Y Coordinate Pairs"
   LOCATE 12, 18
   PRINT "Select Option (1-5) to Change Database Level"
   LOCATE 13, 18
   INPUT "    or 0 to Return to Previous Menu: ", Menu%
 ' 

   SELECT CASE Menu%
 '   

     CASE 0
       ExitMenu% = TRUE
 '

     CASE 1 TO 5
       G.MapDataLevel = Menu%
 '   

     CASE ELSE
       PRINT CHR$(7)
 '

   END SELECT '{ Menu. }

 '

   LOOP UNTIL ExitMenu%
 '

 END SUB '{ DataPointsMenu. }

 
 SUB DrawGrid
 '

   G.LastModCrtX = 0
   G.LastModCrtY = 0
   G.ColorVal = G.GridColor
 
   LatRange% = 90     '

   LatDetail% = 5     ' Since Latitude Lines are straight no need to change

   LongDetail! = .25  ' For Faster Screen Draws this variable can be increased

   '                    For "Publication" Quality vector Graphics try .1#

   '                    (slows screen draws and large increase

   '                    in plot file size)

 '

 '

 ' > If G.LongOption is 1 - All Longitude lines converge at pole

 '   If G.LongOption is 2 - Only draw longitude lines to within 5 Degrees

 '                          of the pole (Default value)

 '

   SELECT CASE G.LongOption
 
     CASE IS = 1
       LatStop% = 90
 '

     CASE IS = 2
       LatStop% = 85
 ' 

   END SELECT '{ G.LongOption. }

 '

   CALL MakeLongitudeLines(LatStop%, LongDetail!)
   CALL MakeLatitudeLines(LatRange%, LatDetail%)
 '

 END SUB '{ DrawGrid. }

 
 SUB DrawOutline STATIC
 '

   G.Outline = TRUE
   G.ColorVal = G.GridColor
   G.LastModCrtX = 0
  
   PolyLine% = TRUE
   Increment# = DEG2RAD / 4
    
   G.Lambda = -DEG180
   G.Lambda2 = -DEG160
   CALL LongitudeFOR(-DEG90, 0, Increment#)
   G.Lambda2 = -DEG100
   CALL LongitudeFOR(0, DEG90, Increment#)
 '

 ' ==================

 ' Insert 1 Longitude

 ' ==================

 '

   G.Lambda = -DEG10
   G.Lambda2 = -DEG100
   CALL LongitudeFOR(DEG90, DEG60, -Increment#)
 '

 ' =================================

 ' Insert 1 Latitude (Bottom Border)

 ' =================================

 '

   G.Phi = DEG60
   G.Lambda2 = -DEG100
   G.Lambda = -DEG10
 '

   DO
     CALL DrawProjection(PolyLine%)
     G.Lambda = G.Lambda - Increment#
     IF G.Lambda < -DEG40 THEN EXIT DO
   LOOP
 '

 ' =================================

 '

 ' =================================

 '

   G.Lambda = -DEG40
   G.Lambda2 = -DEG100
   CALL LongitudeFOR(DEG60, 0, -Increment#)
   G.Lambda2 = DEG30
   CALL LongitudeFOR(0, DEG60, Increment#)
 '

 ' =================================

 ' Insert 2 Latitude (Bottom Border)

 ' =================================

 '

   G.Phi = DEG60
   G.Lambda2 = DEG30
   G.Lambda = -DEG40
 
   DO
     CALL DrawProjection(PolyLine%)
     G.Lambda = G.Lambda - Increment#
     IF G.Lambda < -DEG50 THEN EXIT DO
   LOOP
 '

 ' ==================

 ' Insert 2 Longitude

 ' ==================

 '

   G.Lambda = -DEG50
   G.Lambda2 = DEG30
   CALL LongitudeFOR(DEG60, DEG90, Increment#)
 '

 ' ==================

 ' Insert 3 Longitude

 ' ==================

 '

   G.Lambda = -DEG160
   G.Lambda2 = DEG30
   CALL LongitudeFOR(DEG90, DEG50, -Increment#)
 '

 ' =================================

 ' Insert 3 Latitude (Bottom Border)

 ' =================================

 '

   G.Phi = DEG50
   G.Lambda2 = DEG30
   G.Lambda = -DEG160
 
   DO
     CALL DrawProjection(PolyLine%)
     G.Lambda = G.Lambda - Increment#
     IF G.Lambda < -DEG180 THEN EXIT DO
   LOOP
 
 ' ==================

 '

 ' ==================

 '

   G.Lambda = DEG180
   G.Lambda2 = DEG30
   CALL LongitudeFOR(DEG50, 0, -Increment#)
   G.Lambda2 = DEG140
   CALL LongitudeFOR(0, -DEG90, -Increment#)
 
   G.Lambda = DEG80
   G.Lambda2 = DEG140
   CALL LongitudeFOR(-DEG90, 0, Increment#)
   G.Lambda2 = DEG20
   CALL LongitudeFOR(0, -DEG90, -Increment#)
 
   G.Lambda = -DEG20
   G.Lambda2 = DEG20
   CALL LongitudeFOR(-DEG90, 0, Increment#)
   G.Lambda2 = -DEG60
   CALL LongitudeFOR(0, -DEG90, -Increment#)
  
   G.Lambda = -DEG100
   G.Lambda2 = -DEG60
   CALL LongitudeFOR(-DEG90, 0, Increment#)
   G.Lambda2 = -DEG160
   CALL LongitudeFOR(0, -DEG90, -Increment#)
    
   PolyLine% = FALSE
   CALL DrawProjection(PolyLine%)
  
   G.Outline = FALSE '*

 '

 END SUB '{ DrawOutline. }

 
 SUB DrawProjection (PolyLine%) STATIC
 '

 IF G.ExtensionLobe1 THEN
   G.Outline = FALSE
   LongDeg# = CSNG(G.Lambda * RAD2DEG)
  
   IF LongDeg# >= -40 AND LongDeg# <= -10 THEN
     IF CSNG(G.Phi * RAD2DEG) >= 60 THEN
       G.Lambda2 = -DEG100
       G.Outline = TRUE
     END IF
   END IF
 
   IF LongDeg# >= -180 AND LongDeg# <= -160 THEN
     IF CSNG(G.Phi * RAD2DEG) >= 50 THEN
       G.Lambda2 = DEG30
       G.Outline = TRUE
     END IF
   END IF
   IF G.Outline = FALSE THEN EXIT SUB
 END IF
 
 IF G.ExtensionsLobe2 THEN
   G.Outline = FALSE
   LongDeg# = CSNG(G.Lambda * RAD2DEG)
   IF LongDeg# >= -50 AND LongDeg# <= -40 THEN
     IF CSNG(G.Phi * RAD2DEG) >= 60 THEN
       G.Lambda2 = DEG30
       G.Outline = TRUE
     END IF
   END IF
   IF G.Outline = FALSE THEN EXIT SUB
 END IF
        
 CALL Goode(G.Lambda, CRTRADIUS, G.CrtX, G.CrtY)
        
 IF G.PlotFile THEN
   CALL Goode(G.Lambda, PLOTRADIUS, PlotX#, PlotY#)
   PlotX# = ((25.4# * PlotX#) / .025#) '+ PltXCenter#

   PlotY# = ((25.4# * PlotY#) / .025#) '+ PltYCenter#

 END IF
 '

 G.ModCrtX = FIX((G.CrtX * ASPECT) + XCENTER)
 G.ModCrtY = CINT(YCENTER) - FIX(G.CrtY)
 '

 IF PolyLine% = FALSE THEN G.Visible = FALSE
 '

 ' > This statement eliminates the stray lines going from top to bottom

 ' > for the Transverse Mercator and Cassini Projections

 '

 IF ABS(G.ModCrtY - G.LastModCrtY) > 120 THEN G.Visible = FALSE
 '

 ' > This statement eliminates the stray lines for the Azimuthal Projections

 '

 IF ABS(G.LastModCrtX - G.ModCrtX) > 120 THEN G.Visible = FALSE
        
 IF G.LastModCrtX < -2000 OR G.ModCrtX < -2000 THEN G.Visible = FALSE
         
 IF G.Visible THEN
   Y2# = (G.ModCrtY - G.LastModCrtY) * (G.ModCrtY - G.LastModCrtY)
   X2# = (G.ModCrtX - G.LastModCrtX) * (G.ModCrtX - G.LastModCrtX)
   Distance# = Raise#(X2# + Y2#, .5)
   IF ABS(Distance#) > 20 THEN
     G.Visible = FALSE
   END IF
 END IF
         
 IF G.PlotFile THEN
   IF G.Visible THEN
     PRINT #1, "PD"; STR$(CINT(PlotX#)); ","; STR$(CINT(PlotY#)); ";"
   ELSE
     PRINT #1, "PU"; STR$(CINT(PlotX#)); ","; STR$(CINT(PlotY#)); ";"
   END IF
 END IF
        
 IF G.Visible THEN
   LINE (G.LastModCrtX, G.LastModCrtY)-(G.ModCrtX, G.ModCrtY), G.ColorVal
 END IF
 
 G.Visible = TRUE
 G.LastModCrtX = G.ModCrtX
 G.LastModCrtY = G.ModCrtY
 '

 END SUB ' { DrawProjection. }

 
 SUB FeaturesMenu
 '

 ExitMenu% = FALSE
 '

 DO
   CLS
 '

   LOCATE 2, 19
   PRINT "** Turn Geographical Features On or Off **"
 '   

   LOCATE 5, 22: PRINT "1. Coastlines are";
   IF G.CoastSW THEN
     PRINT " On "
   ELSE
     PRINT " Off"
   END IF
 '   

   LOCATE 6, 22: PRINT "2. Islands are";
   IF G.IslandSW THEN
     PRINT " On "
   ELSE
     PRINT " Off"
   END IF
 '   

   LOCATE 7, 22: PRINT "3. Lakes are";
   IF G.LakeSW THEN
     PRINT " On "
   ELSE
     PRINT " Off"
   END IF
 '   

   LOCATE 8, 22: PRINT "4. Rivers are";
   IF G.RiverSW THEN
     PRINT " On "
   ELSE
     PRINT " Off"
   END IF
 '   

   LOCATE 9, 22: PRINT "5. Country Borders are";
   IF G.BorderSW THEN
     PRINT " On "
   ELSE
     PRINT " Off"
   END IF
 '  

   LOCATE 10, 22: PRINT "6. U.S. State Borders are";
   IF G.StateSW THEN
     PRINT " On "
   ELSE
     PRINT " Off"
   END IF
 '   

   LOCATE 11, 22: PRINT "7. Canadian Province Borders are";
   IF G.ProvinceSW THEN
     PRINT " On "
   ELSE
     PRINT " Off"
   END IF
 ' 

   LOCATE 12, 22: PRINT "8. Austrailian State Borders are";
   IF G.AustSW THEN
     PRINT " On "
   ELSE
     PRINT " Off"
   END IF
 '   

   LOCATE 13, 22: PRINT "9. Mexican State Borders are";
   IF G.AustSW THEN
     PRINT " On "
   ELSE
     PRINT " Off"
   END IF
 '

   LOCATE 16, 23: PRINT "Select Option (1-9) to toggle Feature"
 '

   LOCATE 17, 37: PRINT "- Or -"
 '

   LOCATE 18, 24: INPUT "0 to Return to Previous Menu: ", Menu%
 '   

   SELECT CASE Menu%
 '     

     CASE 0
       ExitMenu% = TRUE
 '

     CASE 1
       IF G.CoastSW THEN
         G.CoastSW = FALSE
       ELSE
         G.CoastSW = TRUE
       END IF
 '

     CASE 2
       IF G.IslandSW THEN
         G.IslandSW = FALSE
       ELSE
         G.IslandSW = TRUE
       END IF
 '

     CASE 3
       IF G.LakeSW THEN
         G.LakeSW = FALSE
       ELSE
         G.LakeSW = TRUE
       END IF
 '   

     CASE 4
       IF G.RiverSW THEN
         G.RiverSW = FALSE
       ELSE
         G.RiverSW = TRUE
       END IF
 '   

     CASE 5
       IF G.BorderSW THEN
         G.BorderSW = FALSE
       ELSE
         G.BorderSW = TRUE
       END IF
 '  

     CASE 6
       IF G.StateSW THEN
         G.StateSW = FALSE
       ELSE
         G.StateSW = TRUE
       END IF
 '

     CASE 7
       IF G.ProvinceSW THEN
         G.ProvinceSW = FALSE
       ELSE
         G.ProvinceSW = TRUE
       END IF
 '     

     CASE 8
       IF G.AustSW THEN
         G.AustSW = FALSE
       ELSE
         G.AustSW = TRUE
       END IF
 '   

     CASE 9
       IF G.MexicoSW THEN
         G.MexicoSW = FALSE
       ELSE
         G.MexicoSW = TRUE
       END IF
 '

     CASE ELSE
       PRINT CHR$(7)
 '

   END SELECT '{ Menu. }

 '

   LOOP UNTIL ExitMenu%
 '

 END SUB '{ FeaturesMenu. }

 
 SUB GetFullCoords (LonI#, LatI#)
 ' Used by GetPKDData subroutine

 '

 STATIC Temp#
 STATIC Temp2#
 '

 ' Longitude Degree1

 CALL ReadInfile(Byte%)
 Temp# = Byte%
 Temp# = Temp# * 7200!
 '

 ' Longitude Degree2

 CALL ReadInfile(Byte%)
 Temp2# = Byte%
 Temp# = Temp# + (Temp2# * 3600!)
 '

 ' Longitude Minutes

 CALL ReadInfile(Byte%)
 Temp2# = Byte%
 Temp# = Temp# + (Temp2# * 60!)
 '

 ' Longitude Seconds

 CALL ReadInfile(Byte%)
 Temp2# = Byte%
 Temp# = Temp# + Temp2#
 LonI# = Temp#
 '

 ' Latitude Degrees

 Temp# = 0
 Temp2# = 0
 CALL ReadInfile(Byte%)
 Temp# = Byte%
 Temp# = Temp# * 3600!
 '

 ' Latitude Minutes

 CALL ReadInfile(Byte%)
 Temp2# = Byte%
 Temp# = Temp# + (Temp2# * 60!)
 '

 ' Latitude Seconds

 CALL ReadInfile(Byte%)
 Temp2# = Byte%
 Temp# = Temp# + Temp2#
 LatI# = Temp#
 '

 END SUB '{ GetFullCoords. }

 
 SUB GetMapData (FileName$) STATIC
 '

 G.Visible = FALSE
 G.LastModCrtX = 0
 
 OPEN "C:\WORK\" + FileName$ FOR RANDOM AS #2 LEN = LEN(PNTData)

 

 TotalRecords& = LOF(2) / LEN(PNTData)

 

 FOR RecordCounter& = 1 TO TotalRecords&

 

   GET #2, RecordCounter&, PNTData

 

   IF PNTData.Header >= G.MapDataLevel THEN

  

     IF PNTData.Header > 5 THEN

       G.ColorVal = PolyLineColor%(PNTData.Header)

       PolyLine% = FALSE

     ELSE

       PolyLine% = TRUE

     END IF

 

     G.Phi = PNTData.Lat * MIN2RAD

     G.Lambda = PNTData.Lon * MIN2RAD

    

     CALL DrawProjection(PolyLine%)

  

   END IF

 

 NEXT RecordCounter&

 

 CLOSE #2

 

 END SUB '{ GetMapData. }

 

 SUB GetMP1Data

 ' This module contains both the GetMP1Data and ParseWord Subroutines.

 ' They are not hooked into the program, but are provided in case the user

 ' wishes to install them and create his or her own coordinate database.

 '

 ' An *.MP1 file is nothing more than an ASCII file that can be

 ' created with a Text editor containing  Latitude in Decimal Degrees

 ' then Longitude in Decimal Degrees separated by a comma or a space.

 ' Comments can also be included on each line as long as they are set

 ' off by an apostrophe (') and are at the end of the line.

 '

 ' The first set of coordinates in the file are understood to be the beginning

 ' of the first PolyLine%. A new PolyLine% is indicated by a blank line at the

 ' beginning of the series of coordinates making up the new line.

 '

 ' OPEN "C:EXAMPLE.PRN" FOR INPUT AS #1

 '

 '    G.Visible = False

 '    G.LastModCRTX = 0

 '    SEEK #1, 1

 '

 '   WHILE NOT EOF(1)

 '

 '     LINE INPUT #1, MP1Rec$

 '

 '     CALL ParseWord(MP1Rec$, TLat$)

 '     LatR = VAL(TLat$) * Deg2Rad

 '

 '     CALL ParseWord(MP1Rec$, TLong$)

 '     LongR = VAL(TLong$) * Deg2Rad

 '

 '     IF VAL(TLong$) = 0 AND VAL(TLat$) = 0 THEN

 '       PolyLine% = False

 '       LINE INPUT #1, MP1Rec$

 '

 '       CALL ParseWord(MP1Rec$, TLat$)

 '       LatR = VAL(TLat$) * Deg2Rad

 '

 '       CALL ParseWord(MP1Rec$, TLong$)

 '       LongR = VAL(TLong$) * Deg2Rad

 '

 '     ELSE

 '       PolyLine% = True

 '     END IF

 '     CALL DrawProjection(PolyLine%)

 

 '   WEND

 '

 'END SUB '{ GetMP1Data. }

 '

 ' SUB ParseWord (PointLine$, Coord$) STATIC

 ' Subroutine to Parse text for *.MP1 Format

 '

 '   Sep$ = " ,"

 '   Coord$ = ""

 '   PointLine$ = RTRIM$(LTRIM$(PointLine$))

 '   LenPointLine% = LEN(PointLine$)

 '   IF PointLine$ = "" OR PointLine$ = "'" THEN

 '     EXIT SUB

 '   END IF

 '   FOR Cnt1% = 1 TO LenPointLine%

 '     IF INSTR(Sep$, MID$(PointLine$, Cnt1%, 1)) = 0 THEN

 '       EXIT FOR

 '     END IF

 '   NEXT Cnt1%

 '   FOR Cnt2% = Cnt1% TO LenPointLine%

 '     IF INSTR(Sep$, MID$(PointLine$, Cnt2%, 1)) THEN ' = 0

 '       EXIT FOR

 '     END IF

 '   NEXT Cnt2%

 '   FOR Cnt3% = Cnt2% TO LenPointLine%

 '     IF INSTR(Sep$, MID$(PointLine$, Cnt3%, 1)) = 0 THEN

 '       EXIT FOR

 '     END IF

 '   NEXT Cnt3%

 '   IF Cnt1% > LenPointLine% THEN

 '     PointLine$ = ""

 '     EXIT SUB

 '   END IF

 '   IF Cnt2% > LenPointLine% THEN

 '     Coord$ = MID$(PointLine$, Cnt1%)

 '     PointLine$ = ""

 '     EXIT SUB

 '   END IF

 '     Coord$ = MID$(PointLine$, Cnt1%, Cnt2% - Cnt1%)

 '     IF Cnt3% > LenPointLine% THEN

 '       PointLine$ = ""

 '     ELSE

 '       PointLine$ = MID$(PointLine$, Cnt3%)

 '     END IF

 '

 ' END SUB ' { ParseWord. }

 END SUB '{ GetMP1Data. }

 
 SUB GetNextCoords (LonI AS DOUBLE, LatI AS DOUBLE)
 ' Used by GetPKDData subroutine

 '

 'Extract Longitude Delta

 CALL ReadInfile(Byte%)
 LonI = LonI + Byte%
 '

 'Extract Latitude Delta

 CALL ReadInfile(Byte%)
 LatI = LatI + Byte%
 '

 END SUB '{GetNextCoords}

 
 SUB GetPKDData
 
 ' extracts data from *.PKD files

 ' This uses the South America Database Only

 
 ' G.Visible = False

 ' PreviousScreenX# = 0#

 
 ' Infile$(1) = "SAC1.PKD"

 ' Infile$(2) = "SAC2.PKD"

 ' Infile$(3) = "SAC3.PKD"

 ' Infile$(4) = "SAC4.PKD"

 ' Infile$(5) = "SAC7.PKD"

 ' Infile$(6) = "SAC8.PKD"

 ' Infile$(7) = "SAC9.PKD"

 ' Infile$(8) = "SAC13.PKD"

 ' Infile$(9) = "SAC14.PKD"

 ' Infile$(10) = "SAC10.PKD"

 ' Infile$(11) = "SAB01.PKD"

 ' Infile$(12) = "SAB2.PKD"

 ' Infile$(13) = "SAB3.PKD"

 ' Infile$(14) = "SAR1.PKD"

 ' Infile$(15) = "SAR2.PKD"

 ' Infile$(16) = "SAR3.PKD"

 ' Infile$(17) = "SAR4.PKD"

 ' Infile$(18) = "SAR5.PKD"

 ' Infile$(19) = "SAR06.PKD"

 ' Infile$(20) = "SAR7.PKD"

 ' Infile$(21) = "SAR8.PKD"

 ' Infile$(22) = "SAR10.PKD"

 
 ' FOR Infil% = 1 TO 22

 ' OPEN "C:\SA\" + Infile$(Infil%) FOR BINARY AS #1

 '

 ' DO

 ' CALL ReadInfile(FeatureType)

 
 ' IF MID$(Infile$(Infil%), 3, 1) = "C" THEN G.ColorVal = 0

 ' IF MID$(Infile$(Infil%), 3, 1) = "B" THEN G.ColorVal = 4

 ' IF MID$(Infile$(Infil%), 3, 1) = "R" THEN G.ColorVal = 1

 '

 ' PointsInLine& = PointCount&(PtCnt&)

 '

 ' CALL GetFullCoords(LonI, LatI) ' - Max Place Holder (Max not used in program)

 '

 ' CALL GetFullCoords(LonI, LatI) ' - Min Place Holder (Min not used in Program)

 '

 ' PolyLine% = False

 
 ' CALL GetFullCoords(LonI, LatI) ' - Use First Coordinate

 
 ' LonR = ConvertCoordToDecDeg#(LonI)

 ' LatR = ConvertCoordToDecDeg#(LatI)

 
 ' G.Phi = LatR * Deg2Rad

 ' G.Lambda = LonR * Deg2Rad

 ' CALL DrawProjection(PolyLine%)

 '

 ' PointsInLine& = PointsInLine& - 1

 '

 ' PolyLine% = True

 ' FOR LoopCount = 1 TO PointsInLine&

 '

 ' CALL GetNextCoords(LonI, LatI) '- Use next coordinates

 ' LonR = ConvertCoordToDecDeg#(LonI)

 ' LatR = ConvertCoordToDecDeg#(LatI)

  
 ' G.Phi = LatR * Deg2Rad

 ' G.Lambda = LonR * Deg2Rad

 ' CALL DrawProjection(PolyLine%)

 '

 ' NEXT LoopCount

 '

 ' LOOP UNTIL Index = LOF(1)

 '

 ' Index = 0

 ' CLOSE #1

 ' NEXT Infil%

 '

 END SUB '{ GetPKDData. }

 
 SUB Goode (DeltaLambda#, Radius#, XCoord#, YCoord#) STATIC
 '

 ' When drawing the outline and the extensions there are a number

 ' of duplications that would be drawn over each other if the following

 ' groups of IF-THEN statements were used. It was easier to define the

 ' necessary Lobe Central Longitude (G.Lambda2) values in the Outline

 ' and DrawProjection (extensions) subroutines and use the Outline

 ' variable as a flag to skip over the following IF-THENs.

  
   IF G.Outline THEN
     GOTO XYPlot
   END IF
  
 IF G.Phi >= 0 THEN
   IF (G.Lambda > -DEG180) AND (G.Lambda <= -DEG40) THEN
     G.Lambda2 = -DEG100
     GOTO XYPlot
   END IF
 
   IF (G.Lambda > -DEG40) AND (G.Lambda <= DEG180) THEN
     G.Lambda2 = DEG30
     GOTO XYPlot
   END IF
 END IF
 
   IF (G.Lambda >= -DEG180) AND (G.Lambda <= -DEG100) THEN
     G.Lambda2 = -DEG160
     GOTO XYPlot
   END IF
 
   IF (G.Lambda >= -DEG100) AND (G.Lambda <= -DEG20) THEN
     G.Lambda2 = -DEG60
     GOTO XYPlot
   END IF
 
   IF (G.Lambda >= -DEG20) AND (G.Lambda <= DEG80) THEN
     G.Lambda2 = DEG20
     GOTO XYPlot
   END IF
 
   IF (G.Lambda >= DEG80) AND (G.Lambda <= DEG180) THEN
     G.Lambda2 = DEG140
     GOTO XYPlot
   END IF
 '

 ' ----------------------------------

 '

 XYPlot:
 ' The DeltaLambda# value is computed at the top of the DrawProjection

 ' subroutine to place the Longitude (G.Lambda#) Value into the correct

 ' quadrant of the map in relation to the center of the full map. It is

 ' used here to establish the same Longitude relationship for the lobe.

  
   Lambda1# = Normalize#(DeltaLambda#, G.Lambda2)
 
   IF ABS(G.Phi) < MERGEPOINT THEN ' (40.73666# * Deg2Rad)

     ' Sinusoidal Projection

     XCoord# = Radius# * Lambda1# * COS(G.Phi)
     YCoord# = Radius# * G.Phi
   ELSE
 '   Part of the MollweideFormula# Function

 '   Placed here to reduce amount of calculations

     SinPhi# = DEG180 * SIN(G.Phi)
 '

 '   This subroutine uses Newton-Raphson iteration to derive the Theta# value

 '

 '   Mollweide Projection

     Start# = G.Phi * .5
     DeltaThetaPrime# = Start#
     DO
       FirstGuess# = MollweideFormula#(DeltaThetaPrime#, SinPhi#)
       DeltaThetaPrime# = DeltaThetaPrime# + DTPINCR#
 '     MollweideFormula# is a user defined function - use The Menu Bar - View

 '     Menu to find it.

       SecondGuess# = (MollweideFormula#(DeltaThetaPrime#, SinPhi#) - FirstGuess#) / DTPINCR#
       Start# = Start# - FirstGuess# / SecondGuess#
       DeltaThetaPrime# = Start#
     LOOP WHILE ABS(MollweideFormula#(DeltaThetaPrime#, SinPhi#)) >= TOLERANCE#
 '

     Theta# = DeltaThetaPrime# * .5
 '

     XCoord# = Radius# * XCONST * Lambda1# * COS(Theta#)
     YCoord# = Radius# * (SQRT2 * SIN(Theta#) - MOLLRFACTOR * Sign#(G.Phi))
 '

   END IF
 '

 ' In addition to the extensive use of IF-THEN statements to define the

 ' Boundries and Central Longitudes of each lobe, the TRICK to

 ' Interrupting and recentering a projection is in the following

 ' line of code. As you know the Homolosine consists of 2 projections that

 ' are merged at 40 Deg. 44 Min. and 11.89 Sec.(40.73666# Decimal Deg.).

 ' The X Coordinate formula of the center projection (Sinusoidal) is copied

 ' and modified by making the G.Phi# (Latitude) value always equal to 0 (Cosine

 ' of 0 is 1) and using the central longitude (G.Lambda2#) of the lobe the

 ' Current Longitude (G.Lambda#) value is within. This value is then added to

 ' the Normal X coordinate output of both projections.

 '

 '     Normal X OUT  | Modified X coord of center Projection

   XCoord# = XCoord# + (G.Lambda2 * Radius#)
    
 ' This line of code is used to turn off PolyLine%s that cross into different

 ' lobes. It could be better (When crossing the equator)!

  
   IF (PreviousPhi# > 0 AND G.Phi < 0) OR (PreviousPhi# < 0 AND G.Phi > 0) THEN
     G.Visible = TRUE
   ELSE
     IF (PreviousLambda2# <> G.Lambda2) THEN
       G.Visible = FALSE
     END IF
   END IF
 '

   PreviousPhi# = G.Phi
   PreviousLambda2# = G.Lambda2
 '

 END SUB '{ Goode. }

 
 SUB LatLongEntry (Title$, Note$)
 '

   CLS
  
   IF Title$ <> "" THEN
     Col = Center%(LEN(Title$))
     LOCATE 2, Col: PRINT Title$
   END IF
 '

   IF Note$ <> "" THEN
     Col = Center%(LEN(Note$))
     LOCATE 4, Col: PRINT Note$
   END IF
 '

    LOCATE CSRLIN + 1, 20
 '

    INPUT "Do you want Grid Lines (Y/N)? ", Answer$
    Answer$ = UCASE$(Answer$)
   
    IF Answer$ = "Y" OR Answer$ = "" THEN
      G.Grid = TRUE
    ELSE
      G.Grid = FALSE
    END IF
 
 '

    LOCATE CSRLIN + 1, 19
    INPUT "Send Output to Plot File (Y/N)? ", Answer$
    Answer$ = UCASE$(Answer$)
   
    IF Answer$ = "Y" THEN
      G.PlotFile = TRUE
    ELSE
      G.PlotFile = FALSE
    END IF
 
 '

 END SUB '{ LatLongEntry. }

 
 SUB LatLongMenu
 '

 ExitMenu% = FALSE
 
 DO
   CLS
 '

   LOCATE 2, 20
   PRINT "** Modify Latitude/ Longitude Display **"
 '

   SELECT CASE G.LongOption
    
     CASE 1
       LOCATE 4, 17
       PRINT "Currently all Longitude lines converge at Pole"
           
     CASE 2
       LOCATE 4, 11
       PRINT "Currently all Longitude lines end 5 Degrees away from Pole"
           
   END SELECT '{ G.LongOption. }

         
   LOCATE 6, 12
   PRINT "1. Change Latitude increment (Currently"; G.LatStep; "Degrees)"
  
   LOCATE 7, 12
   PRINT "2. Change Longitude increment (Currently"; G.LongStep; "Degrees)"
  
   LOCATE 8, 12
   PRINT "3. All Longitude lines converge at Pole"
  
   LOCATE 9, 12
   PRINT "4. Longitude lines end 5 Degrees away from Pole"
  
   LOCATE 11, 14
   INPUT "Select Option (1-4) or 0 to Return to Previous Menu: ", Menu%
 '

   SELECT CASE Menu%
 '    

     CASE 0
       ExitMenu% = TRUE
 '

     CASE 1
       LOCATE 12, 1: PRINT SPACE$(80)
       LOCATE 13, 1: PRINT SPACE$(80)
      
       LOCATE 12, 20
       INPUT "Change Latitude Increment to (5 to 90): ", Increment%
      
       IF Increment% >= 5 AND Increment% <= 90 THEN
         G.LatStep = Increment%
       ELSE
         PRINT CHR$(7)
       END IF
 '

     CASE 2
       LOCATE 12, 1: PRINT SPACE$(80)
       LOCATE 13, 1: PRINT SPACE$(80)
      
       LOCATE 12, 19
       INPUT "Change Longitude Increment to (5 to 90): ", Increment%
      
       IF Increment% >= 5 AND Increment% <= 90 THEN
         G.LongStep = Increment%
       ELSE
         PRINT CHR$(7)
       END IF
 '   

     CASE 3
       G.LongOption = 1
 '      

     CASE 4
       G.LongOption = 2
 '

     CASE ELSE
       PRINT CHR$(7)
 '

   END SELECT '{ Menu. }

 '

   LOOP UNTIL ExitMenu%
 '

 END SUB '{ LatLongMenu. }

 
 FUNCTION LN# (n#) STATIC
 '

 IF n# > 0 THEN
   LN# = LOG(n#)
 ELSE
   PRINT "Error: LN#(n#) Where n# <= 0# "
   SYSTEM
 END IF
 '

 END FUNCTION ' { LN#. }

 
 SUB LongitudeFOR (Begin#, Finish#, Incr#) STATIC
 '

   PolyLine% = TRUE
  
   FOR LatGrid# = Begin# TO Finish# STEP Incr#
     G.Phi = LatGrid#
     CALL DrawProjection(PolyLine%)
   NEXT LatGrid#
 '

 END SUB '{ LongitudeFOR. }

 
 SUB MakeLatitudeLines (LatRange%, LatDetail%)
 '

   G.Outline = TRUE
   FOR LatGrid% = LatRange% TO -LatRange% STEP -1
    
     IF ABS(LatGrid%) < 90 THEN
    
       Even% = (LatGrid% MOD G.LatStep = 0)
       IF Even% THEN
         G.Phi = LatGrid% * DEG2RAD
         PolyLine% = FALSE
         CALL DrawProjection(PolyLine%)
         PolyLine% = TRUE
 
         IF LatGrid% <= 0 THEN
 '

 '       > Southern Lobe 1

 '

           G.Lambda2 = -DEG160
           PolyLine% = FALSE
           CALL DrawProjection(PolyLine%)
           PolyLine% = TRUE
      
           FOR LongGrid% = -180 TO -100 STEP 5
             G.Lambda = LongGrid% * DEG2RAD
             CALL DrawProjection(PolyLine%)
           NEXT LongGrid%
 '

 '       > Southern Lobe 2

 '

           G.Lambda2 = -DEG60
           PolyLine% = FALSE
           CALL DrawProjection(PolyLine%)
           PolyLine% = TRUE
      
           FOR LongGrid% = -100 TO -20 STEP 5
             G.Lambda = LongGrid% * DEG2RAD
             CALL DrawProjection(PolyLine%)
           NEXT LongGrid%
 '

 '       > Southern Lobe 3

 '

           G.Lambda2 = DEG20
           PolyLine% = FALSE
           CALL DrawProjection(PolyLine%)
           PolyLine% = TRUE
      
           FOR LongGrid% = -20 TO 80 STEP 5
             G.Lambda = LongGrid% * DEG2RAD
             CALL DrawProjection(PolyLine%)
           NEXT LongGrid%
 '

 '       > Southern Lobe 4

 '

           G.Lambda2 = DEG140
           PolyLine% = FALSE
           CALL DrawProjection(PolyLine%)
           PolyLine% = TRUE
      
           FOR LongGrid% = 80 TO 180 STEP 5
             G.Lambda = LongGrid% * DEG2RAD
             CALL DrawProjection(PolyLine%)
           NEXT LongGrid%
      
         ELSE
 '

 '       > Northern Lobe 1

 '

           G.Lambda2 = -DEG100
           IF LatGrid% < 60 THEN
             PolyLine% = FALSE
             CALL DrawProjection(PolyLine%)
             PolyLine% = TRUE
        
             FOR LongGrid% = -180 TO -40 STEP 5
               G.Lambda = LongGrid% * DEG2RAD
               CALL DrawProjection(PolyLine%)
             NEXT LongGrid%
           ELSE
             PolyLine% = FALSE
             CALL DrawProjection(PolyLine%)
             PolyLine% = TRUE
        
             FOR LongGrid% = -180 TO -10 STEP 5
               G.Lambda = LongGrid% * DEG2RAD
               CALL DrawProjection(PolyLine%)
             NEXT LongGrid%
           END IF
 '

 '       > Northern Lobe 2

 '

           G.Lambda2 = DEG30
           IF LatGrid% < 50 THEN
             PolyLine% = FALSE
             CALL DrawProjection(PolyLine%)
             PolyLine% = TRUE
        
             FOR LongGrid% = -40 TO 180 STEP 5
               G.Lambda = LongGrid% * DEG2RAD
               CALL DrawProjection(PolyLine%)
             NEXT LongGrid%
           END IF
 
           IF LatGrid% >= 50 AND LatGrid% < 60 THEN
             PolyLine% = FALSE
             CALL DrawProjection(PolyLine%)
             PolyLine% = TRUE
        
             FOR LongGrid% = -40 TO 180 STEP 5
               G.Lambda = LongGrid% * DEG2RAD
               CALL DrawProjection(PolyLine%)
             NEXT LongGrid%
        
             FOR LongGrid% = -180 TO -160 STEP 5
               G.Lambda = LongGrid% * DEG2RAD
               CALL DrawProjection(PolyLine%)
             NEXT LongGrid%
           END IF
      
           IF LatGrid% >= 60 THEN
             PolyLine% = FALSE
             CALL DrawProjection(PolyLine%)
             PolyLine% = TRUE
        
             FOR LongGrid% = -50 TO 180 STEP 5
               G.Lambda = LongGrid% * DEG2RAD
               CALL DrawProjection(PolyLine%)
             NEXT LongGrid%
        
             FOR LongGrid% = -180 TO -160 STEP 5
               G.Lambda = LongGrid% * DEG2RAD
               CALL DrawProjection(PolyLine%)
             NEXT LongGrid%
           END IF
         END IF
       END IF
     END IF
 
   NEXT LatGrid%
   G.Outline = FALSE
 '

 END SUB
 
 SUB MakeLongitudeLines (LatRange%, LongDetail!)
 '

 ' ===========================================

 ' Extension 3 (Right side of Northern Lobe 2)

 ' ===========================================

 '

   G.Outline = TRUE
   G.Lambda2 = DEG30
  
   FOR LongGrid% = -160 TO -180 STEP -1
     Even% = (LongGrid% MOD G.LongStep = 0)
     IF Even% THEN
       IF LongGrid% >= -180 AND LongGrid% < -160 THEN
         G.Lambda = LongGrid% * DEG2RAD
         PolyLine% = FALSE
 '

         FOR LatGrid! = LatRange% TO 50 STEP -LongDetail!
           G.Phi = LatGrid! * DEG2RAD
           CALL DrawProjection(PolyLine%)
           PolyLine% = TRUE
         NEXT LatGrid!
       END IF
    END IF
   NEXT LongGrid%
  
   G.Outline = FALSE
 '

 ' ===============================================

 ' Longitude Lines from 180 degrees to -40 Degrees

 ' ===============================================

 '

   FOR LongGrid% = 180 TO -40 STEP -1
    
     IF LongGrid% < 180 THEN
       Even% = (LongGrid% MOD G.LongStep = 0)
       IF Even% THEN
         IF LongGrid% = -40 THEN
           G.Lambda2 = DEG30
           G.Outline = TRUE
         ELSE
           G.Outline = FALSE
         END IF
 
         G.Lambda = LongGrid% * DEG2RAD
         PolyLine% = FALSE
 '

         North# = LatRange% * DEG2RAD
         South# = -LatRange% * DEG2RAD
     
         IF LatRange% = 85 THEN
           IF G.Lambda = DEG30 THEN
             North# = DEG90
           END IF
  
           IF G.Lambda = DEG140 THEN
             South# = -DEG90
           END IF
 
           IF G.Lambda = DEG20 THEN
             South# = -DEG90
           END IF
         END IF
      
         IF LongGrid% = -40 THEN
           South# = DEG60
         END IF
        
         IF LongGrid% = 80 OR LongGrid% = -20 THEN
           South# = 0
         END IF
        
         CALL LongitudeFOR(North#, South#, -LongDetail! * DEG2RAD)
       END IF
     END IF
   NEXT LongGrid%
 '

 ' ===========

 ' Extension 2 (Left side of Northern Lobe 2)

 ' ===========

 '

   G.Outline = TRUE
   G.Lambda2 = DEG30#
 
   FOR LongGrid% = -40 TO -50 STEP -1
     Even% = (LongGrid% MOD G.LongStep = 0)
     IF Even% THEN
       IF LongGrid% > -50 AND LongGrid% < -40 THEN
         G.Lambda = LongGrid% * DEG2RAD
         PolyLine% = FALSE
 '

         FOR LatGrid! = LatRange% TO 60 STEP -LongDetail!
           G.Phi = LatGrid! * DEG2RAD
           CALL DrawProjection(PolyLine%)
           PolyLine% = TRUE
         NEXT LatGrid!
       END IF
     END IF
   NEXT LongGrid%
 '

 ' ===========================================

 ' Extension 1 (Right side of Northern Lobe 1)

 ' ===========================================

 '

   G.Outline = TRUE
   G.Lambda2 = -DEG100
 
   FOR LongGrid% = -10 TO -40 STEP -1
     Even% = (LongGrid% MOD G.LongStep = 0)
     IF Even% THEN
       IF LongGrid% > -40 AND LongGrid% < -10 THEN
         G.Lambda = LongGrid% * DEG2RAD
         PolyLine% = FALSE
 '

         FOR LatGrid! = LatRange% TO 60 STEP -LongDetail!
           G.Phi = LatGrid! * DEG2RAD
           CALL DrawProjection(PolyLine%)
           PolyLine% = TRUE
         NEXT LatGrid!
       END IF
     END IF
 '

   NEXT LongGrid%
   G.Outline = FALSE
 '

 ' ==============================================

 ' Longitude Lines from 0 degrees to -180 Degrees

 ' ==============================================

 '

   FOR LongGrid% = -40 TO -180 STEP -1
   
     IF LongGrid% = -180 THEN EXIT FOR ' no real need to redraw -180

 
     Even% = (LongGrid% MOD G.LongStep = 0)
     IF Even% THEN
       IF LongGrid% <= -40 THEN
         G.Lambda = LongGrid% * DEG2RAD
         PolyLine% = FALSE
 '

         North# = LatRange% * DEG2RAD
         South# = -LatRange% * DEG2RAD
      
         IF LatRange% = 85 THEN
           IF G.Lambda = -DEG100 THEN
             North# = DEG90
           END IF
   
           IF G.Lambda = -DEG60 THEN
             South# = -DEG90
           END IF
 
           IF G.Lambda = -DEG160 THEN
             South# = -DEG90
           END IF
         END IF
       
         IF LongGrid% = -100 THEN
           South# = 0
         END IF
        
         CALL LongitudeFOR(North#, South#, -LongDetail! * DEG2RAD)
    
       END IF
     END IF
 '

   NEXT LongGrid%
 '

 END SUB '{ MakeLongitudeLines. }

 
 FUNCTION MollweideFormula# (ThetaPrime#, MPhi#) STATIC
 ' From John Snyder's "Map Projections -- A Working Manual"

 ' Used by the Newton-Raphson iteration in the Mollweide portion

 ' of the Map subroutine

 '

   MollweideFormula# = -(ThetaPrime# + SIN(ThetaPrime#) - MPhi#) / (1 + COS(ThetaPrime#))
 '

 END FUNCTION '{ MollweideFormula#. }

 
 FUNCTION Normalize# (LambdaVal#, Lambda0Val#) STATIC
 '

 ' This subroutine is responsible for placing the Longitude (Lambda)

 ' value into the correct part of the map in relation to the selected

 ' Central Longitude (Lambda0) of the map.

 '

 LambdaDiff# = LambdaVal# - Lambda0Val#
 
 DO WHILE ABS(LambdaDiff#) > DEG180
   IF LambdaDiff# < 0 THEN
     LambdaDiff# = LambdaDiff# + DEG360
   ELSE
     LambdaDiff# = LambdaDiff# - DEG360
   END IF
 LOOP
 
 Normalize# = LambdaDiff#
 '

 END FUNCTION ' { Normalize#. }

 
 SUB PlotFileColorMenu
 '

 ExitMenu% = FALSE
 '

 DO
   CLS
 '

   LOCATE 2, 11
   PRINT "** Change Plot File Pen Colors of Geographical Features **"
   LOCATE 4, 33: PRINT "Pen Color Codes"
   LOCATE 6, 29: PRINT "1 - Black  5 - Magenta"
   LOCATE 7, 29: PRINT "2 - Blue   6 - Yellow"
   LOCATE 8, 29: PRINT "3 - Red    7 - Cyan"
   LOCATE 9, 29: PRINT "4 - Green  8 - Brown"
         
   LOCATE 12, 27: PRINT "1. Grid Pen is:"; G.GridPen
   LOCATE 13, 27: PRINT "2. Coast Pen is:"; G.CoastPen
   LOCATE 14, 27: PRINT "3. Country Border Pen is:"; G.BorderPen
   LOCATE 15, 27: PRINT "4. Island Pen is:"; G.IslandPen
   LOCATE 16, 27: PRINT "5. State Border Pen is:"; G.StatePen
   LOCATE 17, 27: PRINT "6. Lake Pen is:"; G.LakePen
   LOCATE 18, 27: PRINT "7. River Pen is:"; G.RiverPen
   LOCATE 20, 14
   INPUT "Select Option (1-7) or 0 to Return to Main Menu: ", Menu%
     
   SELECT CASE Menu%
 '

     CASE 0
       ExitMenu% = TRUE
 
     CASE 1
       LOCATE 20, 1: PRINT SPACE$(80)
       LOCATE 20, 26
       INPUT "Change Grid Pen to (1-8):", NewPen%
       IF NewPen% >= 1 AND NewPen% < 9 THEN
         G.GridPen = NewPen%
       ELSE
         PRINT CHR$(7)
       END IF
 '

     CASE 2
       LOCATE 20, 1: PRINT SPACE$(80)
       LOCATE 20, 23
       INPUT "Change Coastline Pen to (1-8):", NewPen%
       IF NewPen% >= 1 AND NewPen% < 9 THEN
         G.CoastPen = NewPen%
       ELSE
         PRINT CHR$(7)
       END IF
 '

     CASE 3
       LOCATE 20, 1: PRINT SPACE$(80)
       LOCATE 20, 21
       INPUT "Change Country Border Pen to (1-8):", NewPen%
       IF NewPen% >= 1 AND NewPen% < 9 THEN
         G.BorderPen = NewPen%
       ELSE
         PRINT CHR$(7)
       END IF
 '

     CASE 4
       LOCATE 20, 1: PRINT SPACE$(80)
       LOCATE 20, 25
       INPUT "Change Island Pen to (1-8):", NewPen%
       IF NewPen% >= 1 AND NewPen% < 9 THEN
         G.IslandPen = NewPen%
       ELSE
         PRINT CHR$(7)
       END IF
 '

     CASE 5
       LOCATE 20, 1: PRINT SPACE$(80)
       LOCATE 20, 22
       INPUT "Change State Border Pen to (1-8):", NewPen%
       IF NewPen% >= 1 AND NewPen% < 9 THEN
         G.StatePen = NewPen%
       ELSE
         PRINT CHR$(7)
       END IF
 '

     CASE 6
       LOCATE 20, 1: PRINT SPACE$(80)
       LOCATE 20, 26
       INPUT "Change Lake Pen to (1-8):", NewPen%
       IF NewPen% >= 1 AND NewPen% < 9 THEN
         G.LakePen = NewPen%
       ELSE
         PRINT CHR$(7)
       END IF
 '

     CASE 7
       LOCATE 20, 1: PRINT SPACE$(80)
       LOCATE 20, 26
       INPUT "Change River Pen to (1-8):", NewPen%
       IF NewPen% >= 1 AND NewPen% < 9 THEN
         G.RiverPen = NewPen%
       ELSE
         PRINT CHR$(7)
       END IF
 '

     CASE ELSE
       PRINT CHR$(7)
 
   END SELECT '{ Menu. }

 '

 LOOP UNTIL ExitMenu%
 '

 END SUB '{ PlotFileColorMenu. }

 
 FUNCTION PointCount& (PtCnt&)
 ' Used by GetPKDData subroutine

 '

   CALL ReadInfile(Byte%)
   PtCnt& = Byte% * 100
   CALL ReadInfile(Byte%)
   PtCnt& = PtCnt& + Byte%
   PointCount& = PtCnt&
 '

 END FUNCTION '{ PointCount&. }

 
 FUNCTION PolyLineColor% (PolyLineHeader%) STATIC
 '

 SELECT CASE PolyLineHeader%
 '

   CASE 1000 TO 1999
 '   Coast

     PolyLineColor% = G.CoastColor
     PlotPen$ = LTRIM$(STR$(G.CoastPen))
 '

   CASE 2000 TO 2999
 '   Country Borders

     PolyLineColor% = G.BorderColor
     PlotPen$ = LTRIM$(STR$(G.BorderPen))
        
   CASE 3000 TO 3999
 '   Canadian Provinces

     PolyLineColor% = G.StateColor
     PlotPen$ = LTRIM$(STR$(G.StatePen))
       
   CASE 4000 TO 4999
 '   U.S. State borders

     PolyLineColor% = G.StateColor
     PlotPen$ = LTRIM$(STR$(G.StatePen))
        
   CASE 5000 TO 5999
 '   Islands

     PolyLineColor% = G.IslandColor
     PlotPen$ = LTRIM$(STR$(G.IslandPen))
        
   CASE 6000 TO 6999
 '   Lakes

     PolyLineColor% = G.LakeColor
     PlotPen$ = LTRIM$(STR$(G.LakePen))
        
   CASE 7000 TO 7999
 '   Rivers

     PolyLineColor% = G.RiverColor
     PlotPen$ = LTRIM$(STR$(G.RiverPen))
         
   CASE 8000 TO 8999
 '   Australian States

     PolyLineColor% = G.StateColor
     PlotPen$ = LTRIM$(STR$(G.StatePen))
 '

 END SELECT '{ PlineHeader. }

    
 IF G.PlotFile THEN
   IF G.LastPlotPen <> PlotPen$ THEN
     PRINT #1, "SP" + PlotPen$ + ";"
   END IF
 
   G.LastPlotPen = PlotPen$
 END IF
 '

 END FUNCTION '{ PolyLineColor%. }

 
 FUNCTION Raise# (n#, Power#)
 ' Raise a number to a power

 ' (even negative numbers raised to a non-integer power)

 '

 IF n# = 0 THEN
   IF Power# = 0 THEN
     Raise# = 1
   ELSE
     Raise# = 0
   END IF
 ELSE
   Raise# = Sign#(n#) * EXP(Power# * LN#(ABS(n#)))
 END IF
 '

 END FUNCTION '{ Raise. }

 
 SUB ReadInfile (Byte%)
 STATIC Rec AS STRING * 1
 ' Used by GetPKDData subroutine

 '

  Index = Index + 1 'Record Count

  GET #1, , Rec
  Byte% = ASC(Rec)
 '

 ' Convert to Signed Char

  IF Byte% > 127 THEN
    Byte% = Byte% - 256
  END IF
 '

 END SUB '{ ReadInFile. }

 
 FUNCTION Round# (n#, PowerOfTen%) STATIC
 '

 pTen# = 10 ^ PowerOfTen%
 RTemp# = INT(n# / pTen# + .5) * pTen#
 Temp$ = STR$(RTemp#)
 Temp$ = MID$(Temp$, 1, ABS(PowerOfTen%) + 4)
 Round# = VAL(Temp$)
 '

 END FUNCTION
 
 FUNCTION Sec# (n#)
 '

 Cosine# = COS(n#)
 IF ABS(Cosine#) <= 0# THEN
   PRINT "Error: Sec#(n#) where n# ="; n#
   PRINT "       Cosine# ="; Cosine#
   SYSTEM
 ELSE
   Sec# = (1 / Cosine#)
 END IF
 
 END FUNCTION
 
 FUNCTION Sign# (n#)
 ' Return -1 if n# < 0, or +1 if n# >= 0

 '

 IF n# = 0 THEN
   Sign# = 1
 ELSE
   Sign# = ABS(n#) / n#
 END IF
 '

 END FUNCTION '{ Sign. }