HAM Radio 1

home *** CD-ROM | disk | FTP | other *** search

/ HAM Radio 1 / HamRadio.cdr / misc / hamclk / geoclock.doc < prev next >

Wrap

Text File | 1990-01-08 | 75.3 KB | 1,915 lines

Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 Universal Version of Geographic Clock Program Copyright 1988,1989,1990 (C) Joseph R. Ahlgren GEOCLOCK is a registered Trademark Version 4.1 90/01/08 GEOCLK41.ZIP - EGA/VGA/800x600 version GEOMNO41.ZIP - CGA/HGC/MCGA/ATT400/PC3270 version Computer Bulletin Board - 703-241-7980 Joseph R. Ahlgren 2218 N. Tuckahoe St Arlington, VA 22205-1946 - 1 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 Table Of Contents A. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 B. Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . 3 B.1. EGA/VGA/SVGA version (GEOCLK) . . . . . . . . . . . . . . . 4 B.2. CGA/HGC/MCGA/ATT400/PC3270 version (GEOMNO) . . . . . . . . 4 B.3. Mouse . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 B.4. Preparing the registered version . . . . . . . . . . . . . . 6 B.5. Upgrading from version 2.x . . . . . . . . . . . . . . . . . 6 C. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 C.1. Single key functions . . . . . . . . . . . . . . . . . . . . 7 C.2. Commands . . . . . . . . . . . . . . . . . . . . . . . . . . 8 C.3. Command line parameters . . . . . . . . . . . . . . . . . . 14 D. Customizing . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 D.1. Time zone data . . . . . . . . . . . . . . . . . . . . . . . 15 D.2. Cities in GEOCLOCK.DAT and GEO<n>.DAT . . . . . . . . . . . 16 D.3. Default parameters in GECONFIG.DAT . . . . . . . . . . . . . 16 E. Functions for registered users only . . . . . . . . . . . . . . . 16 E.1. Zoom . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 E.2. Distance . . . . . . . . . . . . . . . . . . . . . . . . . . 17 E.3. Time display for cities . . . . . . . . . . . . . . . . . . 17 F. Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 F.1. GEOCLKnn.ZIP . . . . . . . . . . . . . . . . . . . . . . . . 18 F.2. GEOMNOnn.ZIP . . . . . . . . . . . . . . . . . . . . . . . . 18 G. Technical Information . . . . . . . . . . . . . . . . . . . . . . 19 G.1. Ephemeris Data . . . . . . . . . . . . . . . . . . . . . . . 19 G.2. Use of Color . . . . . . . . . . . . . . . . . . . . . . . . 20 G.3. Software structure . . . . . . . . . . . . . . . . . . . . . 21 G.4. Map Generation System . . . . . . . . . . . . . . . . . . . 22 H. Changes from previous versions . . . . . . . . . . . . . . . . . 22 I. Bulletin Board . . . . . . . . . . . . . . . . . . . . . . . . . 27 J. Upgrades and Enhancements for Registered Users . . . . . . . . . 27 K. Registration and License . . . . . . . . . . . . . . . . . . . . 27 - 2 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 A. Introduction GEOCLOCK shows the current time (based on the system clock) with a map of the earth. The current sun position is displayed with a crossed circle, and the part of the earth in sunlight is highlighted. This display is automatically updated every 1 second (for an 8 MHz AT with an 80287) to 20 seconds (for a 5 MHz PC without an 8087). Local sunrise, sunset, and the sun's azimuth and elevation are also displayed. A variety of map backgrounds and other options are available. A graphics adapter and a hard disk are required to run GEOCLOCK. GEOCLOCK is distributed as SHAREWARE. If you use and enjoy the product, you must register and obtain a license for the program. The license includes a few extra features and more maps. See section K. The unregistered version of the program may be distributed freely, provided that the entire unmodified ZIP file is included and no fee is charged other than a nominal amount for media and handling. B. Getting Started GEOCLOCK requires a hard disk, a minimum of 180K available RAM (up to 250K to use VGA and 800x600 modes), and a graphics adapter and monitor. There are two versions of GEOCLOCK. The first is contained in GEOCLK41.ZIP and is designed to support computers with a 256k EGA, VGA, or super VGA board with a compatible color monitor. The second requires both GEOMNO41.ZIP and GEOCLK41.ZIP and is designed to support CGA, Hercules, MCGA, AT&T 640x400, and PC3270 graphics, all in the highest resolution monochrome mode available for that card. To get the program running, do the following: 1. Un-ZIP GEOCLK41.ZIP (and GEOMNO41.ZIP if required) to the directory you will run from. It is best to have a directory dedicated to GEOCLOCK. 2. Set up the program for your graphics adapter. Section B.1 describes the set up procedure for the EGA, VGA, and super VGA (800x600) adapters. Section B.2 describes the set up procedure for the CGA, Hercules, MCGA, PC3270, and AT&T 640x400 adapters. 3. Customize GEOCLOCK for your location. Much customization is possible, and is described in detail in sections D and E. Before you start running GEOCLOCK, you should edit (using any text editor) the GECONFIG.DAT file to specify your local time zone. The value in the initial file specifies the Eastern US time zone. You should change the PCZONE command at the end of GECONFIG.DAT to specify your time zone. 4. If you are a registered user, you need to run the REGISTER program to enable the special features. You may also want to use a mouse - see section B.3. - 3 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 5. Run the program. Just enter GEOCLK (for EGA, VGA, and SVGA) or GEOMNO (for the other adapters) and the program will start. Function Key 1 will provide help, and Escape will terminate the program. B.1. EGA/VGA/SVGA version (GEOCLK) The EGA/VGA/SVGA version of GEOCLOCK requires an EGA, VGA, super VGA (800x600) or close compatible with at least 256k memory, and an EGA, VGA, or multiscanning color monitor. The program uses 640x350, 640x480, and 800x600 16 color graphics. The distribution GEOCLK41.ZIP file contains all the required programs and data bases. The main program file is named GEOCLK.EXE. It will automatically determine whether or not you have a math co-processor (8087,80287, 80387), and use it if you do, or emulate it if you do not. If you have a normal EGA, the program is already configured properly. If you have a VGA or SVGA, you will need to follow one of the procedures below: 1. Set up for VGA or 640x480x16 EGA. To enable 640x480 display, you must include the VGA statement in the GECONFIG.DAT file. This statement tells GEOCLOCK that you have a 640x480 display and how to enter that display mode. You will find a commented out VGA statement at the end of the GECONFIG.DAT file. Simply use any text editor to remove the "REM " at the beginning of the VGA statement, so that the "V" is in column one. If you have a 640x480x16 EGA, you will need to contact your adapter supplier to determine the appropriate parameters for the VGA statement. See section C.2 for a fuller explanation. You might also want to add the SHOWVGA statement to GECONFIG.DAT. This will automatically convert EGA maps to VGA format. 2. Set up for super VGA (800x600x16). To enable 800x600 display, you must include the SVGA statement in the GECONFIG.DAT file. This statement tells GEOCLOCK that you have a 800x600 display and how to enter that display mode. You will find several commented out SVGA statements at the end of the GECONFIG.DAT file, corresponding to the several adapters that support this graphics mode. Simply use any text editor to remove the "REM " at the beginning of the appropriate SVGA statement, so that the "S" is in column one. If your adapter is not listed, you will need to contact your adapter supplier to determine the appropriate parameters for the SVGA statement. See section C.2 for a fuller explanation. It is not necessary to include a VGA statement in addition to the SVGA statement unless your adapter does not use the standard command to enter the 640x480x16 mode. B.2. CGA/HGC/MCGA/ATT400/PC3270 version (GEOMNO) This version of GEOCLOCK is compatible with a wide variety of graphics boards, including all those two color modes supported by the Turbo Pascal 5.0 GRAPH unit. In particular, 640x200 CGA, 720x348 HGC, 640x480 MCGA, 640x400 ATT, and 720x350 PC3270 mode are supported. The 640x350 EGA - 4 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 monochrome mode is NOT supported (this is a four color mode), although the EGA emulation of HGC is supported provided your EGA board permits this. The distribution GEOMNO41.ZIP and GEOCLK41.ZIP files contain all the required programs and data bases. After Un-ZIPping the program, the files configuring the system for your graphics adapter must be built. The installation program GEOCONVT builds these files, installs the proper drivers, and converts the maps to the required format. This program in started by: GEOCONVT <board type> [map file spec] [switches] where board type is CGA, HGC, MCG, ATT, or 327. The [map file spec] specifies which map files are to be converted to the format for your adapter. If omitted, MAP*.EGA is assumed. The switches are zero or more of /D (which specifies that files not required for your particular adapter are to be deleted) and /C (which specifies that map files are to be converted, but no other conversions are to be done). By default, neither option is selected. Specifying /D saves space on your disk, but be sure that you have kept a backup or the original ZIP file before selecting this option. You should specify /C is you are already running GEOMNO and only need to convert a new map file. For the initial setup, I recommend: GEOCONVT CGA (or whatever adapter is appropriate) without any options. You can do a del map*.ega to eliminate the unneeded EGA map files after you are sure that everything is working properly. B.3. Mouse Several GEOCLOCK functions require a graphics cursor for input. These operate from both a mouse and the keyboard. To use the mouse, the INT 33 driver must be loaded. This driver, which comes with most mice, is usually called MOUSE.COM or MOUSE.SYS. The mouse buttons and functions are emulated on the keyboard as follows: Left Mouse Button Control (CTRL) and Page-Up keys Center Mouse Button Escape (ESC) Key Right Mouse Button Alternate (ALT) and Page-Down keys Mouse Motion Arrow and Shift-Arrow keys All the keyboard equivalents work whether or not a mouse is available. In particular, the arrow keys may be used to finely position the cursor after the mouse has moved the cursor to the vicinity of the desired point, and the Escape key can be used if your mouse does not have a center button. B.4. Preparing the registered version - 5 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 The registered version of GEOCLOCK includes an INSTALL batch file to aid in setting up GEOCLOCK on your hard disk. The batch file un-Zips all the required files (include map files), converts the maps as required, and runs the REGISTER program which enables the special features such as Zoom, Distance, and city time display that are available only to registered users. If you do not wish to use this batch file, follow these steps: a. Create a directory for GEOCLOCK on your hard disk, and switch to it. Copy the PKUNZIP.EXE program from the distribution disk to this directory. b. Un-Zip the GEOCLOCK program by entering PKUNZIP A:GEOCLK41 . If your are using the MNO version, also enter PKUNZIP A:GEOMNO41 . c. Un-ZIP all the map files by entering PKUNZIP A:MAP* . If you received multiple disks, you should repeat this command for every disk. d. If you are using a VGA or 800x600, enter PKUNZIP A:VGA* . If you are using an 800x600, also enter PKUNZIP SVGA* . e. Un-Zip the GEODATA file. f. If you are using the MNO version, enter GEOCONVT <code>, where code is CGA, HGC, MCG, ATT, or 327 as appropriate. This converts all the maps to the proper MNO format. g. Copy the REGISTER.EXE file to the hard disk and enter REGISTER . This enables the special features. h. Finally, use the TED editor to customize the configuration. Enter TED GECONFIG.DAT . Change the PCZONE command to your time zone. If you have a VGA or 800x600, add the VGA command. If you have an 800x600, also add the SVGA command. B.5. Upgrading from version 2.x Version 4.x contains many new features which require changes in some of the 2.x files for optimum operation. 3.x files do not require any conversion. Existing 2.x data files will work but cannot take advantage of these new features. The conversion process effects four types of files. a. MAP<n>.EGA. This only effects the EGA/VGA version of GEOCLOCK. The map format was changed to reduce the sizes of the map files. While GEOCLOCK 4.x will display both file formats, processing of the new format is faster. The program CVTMAP.EXE, available on the GEOCLOCK bulletin board, will convert the old to new format. To convert your existing maps, follow this procedure: DEL *.BAK COPY MAP*.EGA MAP*.BAK CVTMAP MAP*.BAK *.EGA DEL *.BAK b. GECONFIG.DAT. This file was required only for GEOMNO in version 2.x. In version 4, this file optionally contains a list of command line parameters (one per line). In addition, two new commands are of particular interest: ZONE, which defines time zone characteristics; and PCZONE, which defines which time zone the PC's local clock is in. The GECONFIG.DAT file - 6 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 provided should be used until you feel the need to change it. GEOCONVT appends any existing GECONFIG.DAT file (including the one provided in GEOMNOnn.ZIP) to the one it produces while setting up GEOMNO. See section D. c. GEOCLOCK.DAT and GEO<n>.DAT. The format of these files has been enhanced to take advantage of the time zone data. The old first line, which specifies the displayed zone and its relationship to the PC clock, is now optional. If it is omitted, it is assumed that PC local time is to be displayed, as specified by the PCZONE command. If a zone code is named, that is the local time displayed. On the subsequent lines, for registered users, the time offset (specified by +n or -n after the !) may be specified as <space><zone code> or <space>*<zone code>, in which case the city time is displayed in the time zone specified by the zone code. If * is included, the time zone name is also displayed. See section D. d. *.BGI files must be replaced with new versions, since version 4 was compiled under Turbo Pascal 5.0. These are included in GEOMNOnn.ZIP. C. Operation To run GEOCLOCK, simply enter "GEOCLK" or "GEOMNO". The initial display is built, and then this display is updated continuously. The program recognizes a variety of functions while running. Each of these is activated by pressing a letter key. These functions are summarized below. C.1. Single key functions Function Key 1 - activates the help system. The first screen is a menu listing all the GEOCLOCK parameters and keys. Select a menu item by pressing the indicated letter displays additional information. You exit the additional information screen and display the main menu by pressing any key. You exit the help system and return to GEOCLOCK display or parameter entry by pressing any non-letter key. F - speed up the rate of change of time per display update. A prompt asks for the number of hours (possibly fractional or negative) for the displayed clock to be incremented during each cycle, e.g., 0.25 for 15 minutes every 1 to 20 second cycle. U - set the interval between screen updates. A prompt asks for the update interval in seconds. When this value is entered, the display is immediately drawn. Subsequently, the screen in updated at the specified interval and synchronized with the clock. Thus, if 15 is specified, the screen will be updated at 0, 15, 30, and 45 seconds past the minute. If your computer is not fast enough to achieve this update interval, the smallest integer multiple of this interval which works will be used. - 7 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 T - change the display time according to prompts in yy/mm/dd hh:mm:ss format. This does not change the system clock. Any missing data will revert to the current local time. Thus "///12:0:0" sets the time to today at 12 noon, while 88 01 01 0 0 0 sets the time to midnight, January 1, 1988. All times in GEOCLOCK use the 24 hour format. R - restore the display time to the current time, and the display update rate to real time. R undoes F, T, and U. P - allows changes to the command line parameters. These commands are listed in section C.2 below. Entering "?" or "HELP" at the prompt will activate the help system. S - select a map. When this key is pressed, a list of available maps is displayed with their coordinates, title, and North-South distance. The highlighted line corresponds to the current map. The cursor keys can be used to scroll through this list. When the <ENTER> key is pressed, the highlighted map will be displayed. Some very early GEOCLOCK maps did not have titles. If you have any of these maps, the FIXMAP program, available on the GEOCLOCK RBBS (703-241-7980) will add the proper titles. X - return to DOS. Escape - return to DOS. C.2. Commands GEOCLOCK allows several command line parameters which control the display. These parameters may also be entered in response to prompts from the "p" function above, included on the DOS command line, included in the GECONFIG.DAT file, or included in a GEO*.DAT file. The DCGE column indicates any restrictions on the command. "D" indicates that this command is the initial condition of GEOCLOCK when it is started. "C" indicates that the command may be included on the GEOCLOCK command line. "G" indicates the command remains in effect until overridden by another command (otherwise the effect of the command is automatically removed when the displayed map is changed). Finally, "E" indicates that the command has effect only in the EGA/VGA/SVGA (GEOCLK) version. command DCGE comments ? ---- displays list of commands. HELP ---- displays list of commands. - 8 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 REM -C-- remark. The rest of the parameter is ignored. MAP -C-- MAP (without a number) brings up the map selection menu, similar to the "S" command. This may be entered on the command line or in the GECONFIG.DAT file, in which case the map selection menu will be displayed before the program starts. NOMAP -CG- does not display any background map. MAPn -CG- displays appropriate map. Map1 is the default. The GEO*.ZIP files include two maps. MAP1 is a rectilinear projection of the entire Earth. MAP2 is a map of the 48 states. The EGA/VGA/SVGA version also includes MAP2000, which is a North Polar projection map. Other maps are available as detailed in section K. Polar projection maps work only with the EGA/VGA/SVGA version of GEOCLOCK. NOSCR -C-E This command forces EGA maps to be handled the same way VGA and SVGA maps are handled. In particular, only one display frame is used, so the smooth animation is lost, but the display update is somewhat faster, and the yellow sun symbol rather than the dark crossed circle is used to indicate sun position. SHOWVGA -C-E This command causes all EGA maps to be automatically expanded (by duplicating some rows) to VGA resolution and displayed as VGA maps. This does not change the map resolution, but does change the text and sunlight resolution. SHOWSVGA -C-E This command causes all EGA and VGA maps to be automatically expanded (by duplicating some rows and pixels within rows) to SVGA resolution and displayed as SVGA maps. This does not change the map resolution, but does change the text and sunlight resolution. - 9 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 VGAa/b/c/d -C-E This enables VGA display. If this command is not included in the GECONFIG.DAT file, VGA maps may not be displayed. The arguments indicate decimal the values to be loaded into the AX, BX, CX, and DX registers before the call to INT 10 to enter VGA mode. For true VGAs, the parameters are optional: VGA18/0/0/0 is assumed. Check with you display adapter supplier if you are not sure of the correct parameters to use. DO NOT include this command unless you have a 640x480 EGA, a VGA, or super VGA adapter and a VGA or multisync monitor: your monitor may be damaged if it does not support the vertical and horizontal frequencies generated by the VGA. SVGAa/b/c/ -C-E This enables SVGA (800x600) display. If this command is d not included in the GECONFIG.DAT file, SVGA maps may not be displayed. The arguments indicate the values to be loaded into the AX, BX, CX, and DX registers before the call to INT 10 to enter SVGA mode. For the Paradise SVGA, the parameters are optional: SVGA88/0/0/0 is assumed. Check with you display adapter supplier if you are not sure of the correct parameters to use. DO NOT include this command unless you have a super VGA adapter and a multisync monitor: your monitor may be damaged if it does not support the vertical and horizontal frequencies generated by the SVGA. MARK -CG- displays markers for the cities in geo*.dat. See section D.3 NOMARK DCG- does not display city markers or city names. NOCITY DCG- does not display city names for the cities in geo*.dat. CITY -CG- displays city names. QUIET DCG- does not beep on screen update. SOUND -CG- beeps each time the screen is updated. NOLINE DCG- does not display any latitude/longitude lines. - 10 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 LINEnn -CG- displays latitude/longitude lines every nn degrees, unless that would result in more than 40 lines. If nn is 0 or missing, the current latitude and longitude line intervals are not changed but lines are enabled, and thus LINE undoes NOLINE. TLINCnn -CG- same as LINEnn, except only affects Latitude lines. GLINCnn -CG- same as LINEnn, except only affects Longitude lines. TLSPECnn -CL- displays one latitude line at nn. GLSPECnn -CL- displays one longitude line at nn. Up to 20 TLSPEC and GLSPEC lines may be specified. CLINE DCG- removes all TLSPEC and GLSPEC lines. HIDELL DCG- does not label latitude/longitude lines SHOWLL DCG- labels latitude/longitude lines DRAWLINE --L- This command draws a line between (lat1,long1) and lat1 long1 (lat2,long2) on the current map. All latitudes and lat2 long2 longitudes are in degrees and fractions. The command color operates on when contained in a GEO*.DAT file that is processed for the map. Color is the color in which the line will be drawn. See section G.2 for an explanation of the use of color. If omitted, color defaults to 5, which is displayed as yellow. Example: DRAWLINE 38.9 -77.0 34.0 -118.3 0 draws a line between Washington DC and Los Angeles in color 0. - 11 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 DRAWCIRCLE --L- This command draws an ellipse centered at latcenter (latcenter,longcenter) and with latitude (vertical) longcenter radius latcenter and with longitude (horizontal) radius latradius longcenter. All latitudes and longitudes are in degrees longradius and fractions. The command operates on when contained in color a GEO*.DAT file that is processed for the map. Color is the color in which the line will be drawn. See section G.2 for an explanation of the use of color. If omitted, color defaults to 5, which is displayed as yellow. Example: DRAWCIRCLE 38.9 -77.0 10 20 6 draws an oval centered on Washington DC that is 10 degrees from the center to the northernmost point, and 20 degrees from the center to the easternmost point, and in color 6. INCLUDE ---- When contained in a GEO*.DAT file, this command suspends <file> reading from the file being processed, and processes all commands in the <file>. When all commands in that file have been processed, reading resumes from the original file. INCLUDE may be nested up to ten levels. Include may also be used in response to the "P" command. In this case, the named file will be included at the end of the GEOn.DAT file for the map currently displayed. The effect of this command will be negated when a new map is selected or a new file is specified with INCLUDE. NORM -CG- highlights sunlit area. REV -CG- highlights area not sunlit (appropriate for LCD displays) LIGHT -CG- highlights entire screen, and does not show sun symbol. DARK -CG- highlights no area, and does not show sun symbol. FLICKER -C-E This command forces GEOCLOCK to bypass the video BIOS and issue changes to the video memory start address and palette directly to the video hardware. This is necessary to prevent flickering or blinking of the display on some graphics adapters. NOBLINK -C-E This command prevents the markers from blinking on the "D"istance screen. You may want to use the MCOLOR command with NOBLINK to improve marker readability. - 12 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 MCOLORxxyy -C-E MCOLOR sets the colors of the Markers on the "D"istance screen. Marker 1 is set to xx, and Marker 2 is set to yy. For example, MCOLOR5962 sets Marker 1 to 59 (bright cyan) and Marker 2 to 62 (yellow). SHOWCH DCGE display screens as they are built HIDECH -CGE displays screens only after they are completed. PS2BUG -CGE use if, with SHOWCH set, the display goes blank during GEOCLOCK operation or after GEOCLOCK termination. This works around an error in the PS/2 VGA BIOS. NORAM DCGE use if map display is trashed. This option adds approximately 25K to the memory required to execute GEOCLK. USERAM -CGE use if there is insufficient RAM to run GEOCLOCK. This option moves the disk buffer to an area within the VIDEO RAM. Some EGA boards, including the ATI EGA wonder, are not compatible with the DMA-s of some computers, and this option will cause the display to be trashed or will cause disk errors. USERAM is also not compatible with the VGA and SVGA, and may lead to map display errors. SHOWMN -CG- displays the map number and name in the upper right hand corner. This data may overlap the latitude/longitude display. HIDEMN DCG- does not display map name and number. FULL DCG- displays local location, time, and full ephemeris data. SUN -CG- displays location, time, and sunrise/sunset data TIME -CG- displays local date and time at bottom of screen. NONE -CG- displays no text data. - 13 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 SUNANGLEx -CG- sets the elevation angle of the sun used to compute sunrise and set. The default is -0.8333 degree, corresponding to the sun just breaking the horizon considering refraction effects. SUNANGLE-6.0 sets this angle to -6 degrees, which defines civil sunrise and set. -12 is Nautical sunrise and sunset, while -18 is Astronomical sunrise and sunset. This parameter does not effect the terminator line calculations. ZONE --G- defines a time zone. See section D.2. PCZONE --G- defines the time zone the PC's clock is in. See D.2. EQUINOX -CG- allows the exact GMT of an equinox to be specified (e.g., EQUINOX 88/09/22 17:29). This data is used to calibrate the sun position calculation to improve the accuracy near the equinoxes (while degrading it far from the equinoxes). Personally, I do not think this is a very good idea, but I am tired of defending my position. The current system computes equinoxes within a few minutes. CSET --GE allows the screen colors to be changed interactively. COLORnxxyy -CGE changes screen color without interaction. "n" specifies the feature number (0- 7) to be changed. Feature number n will display color xx, and feature n+8 will display color yy. Thus COLOR56262 will cause feature numbers 5 and 13 to display as 62 (bright yellow). See Section G.2 for a explanation of how color is used in GEOCLOCK. FAST -CG- Forces GEOCLOCK to use a faster but slightly less accurate algorithm for drawing the sunlit area. This is the default for systems without an 80x87. SLOW -CG- Forces GEOCLOCK to use the high accuracy algorithm for drawing the sunlit area. This is the default for systems with an 80x87. On systems with an 80x87, the difference in speed between SLOW and FAST is negligible, while on those systems without an 80x87, FAST is approximately twice the speed of SLOW. These options do not effect polar projection maps. C.3. Command line parameters - 14 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 Any of the commands (other than ZONE, PCZONE, CSET, DRAWLINE, DRAWCIRCLE, and INCLUDE) in section C.2 above may be entered on the command line that invokes GEOCLOCK. These commands will be in effect when GEOCLOCK begins, and override commands placed in the GECONFIG.DAT file. D. Customizing After the program has been extracted and is operating, you may wish to customize it for your computer. The primary way to customize the program is through some special text files. These files can be customized with any text editor. GECONFIG.DAT describes your graphics system, defines the time zones, and gives the default setting for the program. The GEOCLOCK.DAT and GEO<n>.DAT files specify the cities and time zones to be displayed with each map. Sample GECONFIG.DAT and GEOCLOCK.DAT files are provided with the program, and you examine these examples to help you prepare your own custom versions. D.1. Time zone data Time zones are user defined in GEOCLOCK. Each zone (e.g., Eastern) is specified by giving its code name (e.g., ET), the names of summer and standard times (e.g., EDT and EST), the number of hours the time is ahead of GMT (e.g., -4 and -5), and the times between which summer time is in effect (e.g., 88/04/24 8:00:00 GMT and 88/10/30 8:00:00 GMT). The zones are referenced by their code names, and thus the zone data need only be updated once per year (sometime during the winter) and in only one place (where the zones are specified). It is most convenient to include the zone specifications in the GECONFIG.DAT file. If the ZONE commands are not for the correct year, GEOCLOCK will automatically update them by changing each date to the closest date in the correct year which falls on the same day of the week. For example, 89/10/29 would change to 90/10/28, since both days fall on Sunday. This update is not necessarily correct, and I recommend that the ZONE commands be kept current. The ZONE command takes 7 parameters: 1) a code name for the time zone (referenced by PCZONE, and GEO<n>.DAT files), 2) the name of the standard time, 3) the number of hours standard time is ahead of GMT (thus negative for US locations), 4) the name of the summer (daylight) time, 5) the number of hours summer time is ahead of GMT, 6) the date and time (GMT) to switch from standard to summer time, in the format yy/mm/dd:hh:mm:ss, with trailing data optional (e.g., 88/10/30:8), 7) the date and time (GMT) to switch from summer time to standard time. If a zone does not change during the year, the last four parameters may be omitted. This command is best used in the GECONFIG.DAT file. The PCZONE command sets the relationship between the local time on the PC's clock and GMT, i.e., declares which time zone the PC's clock is in. It takes one parameter - a time zone code, as defined in the ZONE command. - 15 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 This command is best used in the GECONFIG.DAT file, and it must follow the ZONE command that it references. D.2. Cities in GEOCLOCK.DAT and GEO<n>.DAT Cities may be overlaid on the maps. They are specified in GEO<n>.DAT files. For map number n (e.g., 2, the 48 states map), these cities are read from GEOn.DAT (e.g., GEO2.DAT) if that file exists. If the file does not exist, cities are read from GEOCLOCK.DAT. The first entry in a GEO<n>.DAT file specifies the time zone code to be used for the standard time display. It consists of a line with a single zone code. If this line is omitted, the code for PCZONE is used. Ordinarily, this code should match the time zone code for the first city in the file. Following this time zone entry, command line parameters may be optionally included. The command line parameters will be processed after both the command line and the GECONFIG.DAT file parameters, and thus will override entries there. The command REM may be used to add comments to the file. Subsequent entries in the file specify the name and locations of cities to be displayed. Each entry consists of the latitude, longitude, and name of the city. Latitude and longitude are in degrees and fractions (NOT degrees, minutes, and seconds), with North and East positive. Thus, most US locations have positive latitude and negative longitude. The first city specified is used for calculating the sunrise, sunset, and the azimuth and elevation angles for the sun. D.3. Default parameters in GECONFIG.DAT The GECONFIG.DAT file may be used to specify default setting and time information. If you are using GEOMNO, the first four lines must be as written by the GEOCONVT program. They give specification data for your graphics system. Subsequent lines contain command line parameters. There should be no leading spaces on these subsequent lines. This file is processed BEFORE the command line parameters are executed, so the command line will override parameters specified here. If you have a VGA or 800x600, the VGA and SVGA commands should be in GECONFIG.DAT. E. Functions for registered users only The following functions are available to registered users only. See section K for details on how to register. E.1. Zoom - 16 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 This function allows the user to change the map background using the cursor. A mouse or the arrow keys can be used. To invoke the function, press the letter Z. The screen will be stabilize without any time or sunlight information, and an Iron-Cross type cursor will appear. Use the mouse and/or arrow keys (shift-arrows move 8 times faster than non-shifted arrows) to locate a position on the map. Each press of the right or left button on the mouse, or CONTROL or ALTERNATE keys, or Page-Up or Page-Down keys on the keyboard, will switch to a new map containing that point. The left button "zooms in" while the right button "zooms out." The cursor will remain at the specified latitude/longitude during the switch. When the desired map is displayed, press the middle button or the ESCAPE key to return to time display. This function is available only to registered users. E.2. Distance and Azimuth This function provides a display of the coordinates of three selected points, and the distances between them, as controlled by a mouse or the keyboard. The function is invoked by pressing the letter D. Point 1 is selected by the left button of the mouse or the CONTROL key or Page-Up key on the keyboard. Point 2 is selected by the right button or the ALTERNATE key or the Page-Down key. Point 3 is the current cursor position. To return to the time display, press the middle button or ESCAPE. To maintain smooth cursor movement, the distance and coordinate displays are updated only when the cursor is not moving. Pressing the "." key will display coordinates in degrees and fractions, while the "'" key will display coordinates is degrees, minutes, and seconds. Pressing "A" will display the azimuth between the two points (the azimuth at the first toward the second, and the azimuth at the second toward the first, with North 0 and East 90) and the distance in kilometers, while pressing "D" will display the distance between the points in miles and kilometers. These functions are available only to registered users. E.3. Time display for cities For registered users only, additional control over city placement, color, size, and local time display is possible. All are marked by characters appearing after an exclamation point (!) on a city line in GEO<n>.DAT. This new data consists of an optional string of characters as follows: - 17 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 A - show city name Above mark B - show city name Below mark L - show city name Left of mark R - show city name Right of mark (if none of above specified, use best) Y - show city name in color 5 (Yellow by default) E - show city name in 8x14 font (8x8 by default) number - show city name in color number (e.g., 6 shows city name in color 6). After these optional codes, the line may be optionally followed by a space and a time zone code. If included, this specifies that the local time for that city is to be displayed to the right of the city name. If a "*" is included, the name of the time zone will be displayed in addition to the time. For example: ET 38.90 -77.02 Washington !E 42.65 -73.75 Albany NY !Y 35.08 -106.65 Albuquerque NM ! *MT 42.28 -83.75 Ann Arbor MI !A 33.75 -84.39 Atlanta GA 44.30 -69.76 Augusta ME 33.52 -86.81 Birmingham AL ! CT 46.80 -100.78 Bismarck ND !B *CT F. Files F.1. GEOCLKnn.ZIP GEOCLOCK.DOC This file. GEOCLOCK.DAT An example of a customization file for GEOCLOCK. See section B.3 for the details of the contents of this file. GECONFIG.DAT A starter for the configuration file for GEOCLOCK. See section D for details. GEOCLK.EXE GEOCLOCK version for EGA, VGA, and super VGA. MAP1.EGA EGA database for MAP1 (world). MAP2.EGA EGA database for MAP2 (48 states). MAP2000.EGA EGA database for MAP2000 (North Polar Projection). MAILER. Printer file to aid registration. Two other ZIP files are available to support GEOCLK for the VGA and SVGA. VGA1-2.ZIP contains MAP4001 (VGA world) and MAP4002 (VGA 48 states). SVGA1-2.ZIP contains MAP6149 (SVGA world) and MAP6002 (SVGA 48 states). F.2. GEOMNOnn.ZIP README.MNO Instructions for setup of GEOMNO. - 18 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 GEOMNO.EXE GEOCLOCK version for two color graphics. GEOCONVT.EXE Installation program to select drivers and font files, write configuration file, and convert maps to specific graphics format. See section B.2 for instructions on the operation of this program. *.BGI Various graphics drivers (Turbo Pascal 5.0). *.FON Various font files. G. Technical Information G.1. Ephemeris Data and Accuracy. The ephemeris data in GEOCLOCK was derived by fitting data from "Interactive Computer Ephemeris" (ICE) to two twelfth order polynomials. One polynomial computes the sun's latitude, while the other computes the sun's longitude at noon GMT. Both assume a 365.242199 day year. They were made by a least squares fit to 400 points around 1989 data. In this interval, the maximum and RMS latitude errors are 0.016845 and 0.004049 degrees, while the maximum and RMS longitude errors are 0.059805 and 0.016630 degrees. The fit has been tested against 1986 sun rise and set data, and with 1985 through 2000 spring equinox times, and is within a few minutes in time, but obviously there are no guarantees of the accuracy. ICE is available on many astronomy bulletin boards, or from: Nautical Almanac Office Code FA U. S. Naval Observatory Washington, DC 20392 The terminator is shown as the locations where the horizon bisects the sun without regard to atmospheric effects, so the sunrise occurs earlier and the sunset occurs later than the terminator indicates. The sun rise and sun set times are computed as the times that the sun's center is a specified angle above or below the horizon, without regard for atmospheric effects. The default value, -0.8333, corresponds to civil sun rise and set, where the visible edge of the sun just breaks the horizon. Some future version of GEOCLOCK may include the moon, planets, and artificial satellites. This requires a few pascal routines that I just do not have the time to develope. If anyone can help me with the routines below I will be grateful. {Global Variables that are set by other software } var JulianDate: real; {Julian Date/Time, with 89/01/01 0:0:0 GMT = 16072.0000} SunZenithLatitude: real; {geographic latitude of the sun at JulianDate} SunZenithLongitude: real; {geographic longitude of the sun at JulianDate} - 19 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 {Special Types} type ObjectType = (Moon,Mercury,Venus,Mars,Jupiter,Saturn,Uranus,Neptune,Pluto); ElementType = record SatelliteName: string; EpochTime: real {JulianDate/Time}; Inclination: real {degrees}; RAofNode: real {Degrees}; Eccentricity: real {dimensionless}; ArgOfPerigee: real {degrees}; MeanAnomaly: real {degrees}; MeanMotion; real {revolutions/day}; DecayRate: real {revolutions/day/day}; EpochRev: integer {dimensionless}; SemiMajorAxis: real {kilometers}; end; procedure SkyPosition( ObjectID: ObjectType; var ZenithLatitude, ZenithLongitude: real); { returns the earth (not sun) latitude and longitude (not right ascension and declination) where the specified object is at Zenith.} procedure CalculateSatellitePosition( var Elements: ElementType; var Lat,Long,Alt: real); {Calculates the earth centered latitude, longitude, and altitude of the satellite described by "Elements" at time JulianDate. Lat" and "Long" are in degrees (East longitude positive), and "Alt" is in kilometers} G.2. Use of Color The EGA graphics adapter provides for the simultaneous display of 16 colors from a palette of 64. Most programs use the default palette, which roughly corresponds to the colors provided by the CGA in text mode. The EGA/VGA/SVGA version of GEOCLOCK does not use this standard palette. The 16 numbers specifying a color from the color palette are used to represent 16 features displayed by GEOCLOCK. The use of the 16 feature numbers is as follows: - 20 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 feature use feature+8 use 0 Political Bdy (dark) 8 Political Bdy (light) 1 Water (dark) 9 Water (light) 2 Land (dark) 10 Land (light) 3 Land/Water Bdy (dark) 11 Land/Water Bdy (light) 4 Text Background (dark) 12 Text Background (light) 5 Aux Text Color (dark) 13 Aux Text and Sun (light) 6 Lat/Long Lines (dark) 14 Lat/Long Lines (light) 7 Frame and Text 15 Frame and Text The actual colors displayed are determined by the formula: color value = B + 2*G + 4*R + 8*b + 16*g + 32*r, where B = bright blue b = dim blue G = bright green g = dim green R = bright red r = dim red Some typical colors are: name RGBrgb color value black ------ 0 white RGBrgb 63 dark blue -----b 8 blue --B--- 1 light blue --Brgb 57 dark green ----g- 16 green -G---- 2 light green -G-rgb 58 brown R---g- 20 light yellow RG-rgb 62 red R----- 4 bright red R--rgb 60 G.3. Software structure GEOCLOCK is written entirely in Turbo Pascal version 5.0, except for the mouse interface routines and a few inline sections required for speed. It has approximately 7300 lines of source code. It uses 8 byte reals for most calculations, and thus relies on the 80x87 emulation package for systems without a math co-processor. The EGA/VGA/SVGA version uses a custom graphics package which provides access to special hardware features (such as independent control of screen planes, disk I/O directly to the video memory, fast fill, and preserving the graphics memory during text display) that are not available in the EGAVGA.BGI driver. The monochrome version uses the GRAPH unit, and builds a screen image in RAM before copying the image in its entirety to video memory. The GRAPH unit functions other than PUTIMAGE are not used except for a few special - 21 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 applications, such as drawing the graphics cursor, and updating the position and distance displays in the distance function. G.4. Map Generation System The maps used for the GEOCLOCK program were produced by a custom data base and software system. This system consists of a highly compressed vectorized map data base and a set of programs to convert the data into custom maps. The data base is a PC conversion of World Data Bank II. It contains approximately 5.7 million vectors covering coastlines, islands, lakes, rivers, and similar geologic features, together with political boundary data. It covers the entire earth, and included features are accurate to approximately 600 meters. World Data Bank II was converted to this custom PC format by an ad hoc program which took advantage of specific features of both data bases. In its operational form, the PC data base uses approximately 0.84 bytes per data point, and in archival form takes approximately 0.5 bytes per data point. The data base is therefore easily stored and manipulated on an AT class PC. Custom maps are generated by using two programs. The first, MAPGEN, reads the appropriate parts of the map data base and produces separation files of the required feature data as EGA or VGA raster images. Rectangular, polar, or Lambert projections may be used in forming these separation files. Depending on complexity and scale, this process takes between 30 and 300 seconds on an AT with a co-processor. The second, MOVIE, allows the user to process the separation files to select the features and colors for the final map, including filling areas. This program also writes the map in a rasterized compressed format with headers and trailers so that it may be easily used as background data for other programs (for example, the GEOCLOCK program). Both these programs, and the converted data base, are proprietary and not yet available to the general public. World Data Bank II is available from National Technical Information Center, Springfield, VA, for about $1000 on 5 reels of tape. H. Changes from previous versions H.1. Version 2.3 to version 2.4 CSET, Zoom, and Distance functions were added. If GEO<n>.DAT exists, it is used for city and time zone information when displaying MAP<n>.EGA, otherwise GEOCLOCK.DAT is used, e.g., GEO2.DAT is used while displaying MAP2.EGA. If the system detects hardware incompatibility, a prompt for proceed/abort is given. A few EGA boards, and apparently the IBM VGA board, are not properly detected by this program. However, they do appear to work. - 22 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 H.2. Version 2.4 to version 2.5 The two color graphics version of GEOCLOCK was made compatible with EGA version and will be distributed as GEOMNOnn.ZIP. Offset from local PC time to display time added. Latitude and Longitude Lines were added with the LINE parameter. MAP1 has been modified to remove the lines so that all maps are under the control of this feature. Graphics hardware detection software removed. As opposed to most software changes, this "feature" has proven to be only an annoyance. If you do not have proper graphics hardware to support the version, the results are unpredictable. A fatal message is still issued if the version requires an 80x87 but your system does not have one. H.3. Version 2.5 to version 2.6 Version 2.5 was not distributed correctly. Version 2.6 corrects this error. The version 2.5 code does not execute correctly on systems without a Numeric Co-Processor. H.4. Version 2.6 to version 2.7 The code which generates latitude and longitude lines was improved to give additional control over line colors. An option to label the latitude and longitude lines was added. The latitude lines are drawn from North to South. The function "CSET" was added to the non-registered version of the program. The registration of the markers and the location names was improved for the EGA version. Cities whose names would overlap cities already displayed are suppressed. The processing of Longitudes was generalized so that maps with 180 degrees in as an interior longitude can be processed. The processing for the zoom function was generalized to preserve cursor locations for these maps. The DARK and LIGHT options were added to the display control. The SHOWCH and HIDECH options were added. The use of the display buffer was improved in the EGA version. A function giving a help screen when function key F1 is pressed was added. H.5. Version 2.7 to version 2.8 The TIMEB command was added to display time and time zone name at the bottom of the screen. The COLOR command was added to change the palette without interacting with CSET. - 23 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 The implementation of city name was changed to allow longer city names. Users can control the position, font size, and color of city names (registered users only). These features were extended to include the monochrome version. Local time for each city may be displayed (registered users only). Precision of the cursor used for zoom and distance improved. The SHOWMN and HIDEMN commands were added to display the map name and number on screen. The PS2BUG command was added to help users work around a bug in the PS/2 VGA BIOS. Some changes in screen handling were made to minimize the effect of this problem even when PS2BUG is not selected. The speed of the non-80x87 version was substantially improved (approximately 1/3 faster) by reorganizing the terminator line calculations. H.6. Version 2.8 to version 3.0 The handling of time zones was completely revised. The GECONFIG.DAT file contains the descriptions of all world time zones, including the names of summer and standard times, their offsets from GMT, and the times of the year that summer time is in effect. The GEO<n>.DAT file formats were make consistent with this standard. Therefore, all time zone information can be concentrated in one place, and the GEO<n>.DAT files can refer to this information symbolically. The old format is still accepted, but mixing the two is not recommended. The map file format, and the display palette, were changed to reduce map file size and drawing time. The program CVTMAP was developed to convert the old map file format to the new map file format. Conversion is not required but is recommended. A problem affecting the distance measuring function, and use of the mouse, for the hercules and ATT 400 versions was fixed. A problem which sometimes caused city name and time data to overwrite the legend data at the bottom of the screen was fixed. The control of the "zoom" feature was improved so that the left button "zooms-in" and the right button "zooms-out". A serious error in GEOCONVT affecting the MCGA mode was fixed. That is problem was not noticed earlier tells me that the MCGA is not exactly widely used! The format of the GECONFIG.DAT file was extended so that the default command line parameters can be set and time zone characteristics can be defined. The separate versions for systems with and without math co-processors were eliminated. The program automatically detects the math co-processor, and uses it or emulates it as appropriate. This slows the program slightly but reduces the size of the distribution file dramatically. The FAST and - 24 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 SLOW parameters were added to control the method used to draw the terminator (the FAST method is much faster on systems without an 80x87). The EQUINOX parameter was added to optionally improve the accuracy of GEOCLOCK near the equinoxes, although this degrades the overall accuracy of the program. H.7. Version 3.0 to 3.1 The NORAM and USERAM command line parameters were added, and the default was changed to NORAM. The calculation of sun rise and sun set times was improved, especially in areas in extreme latitudes. The display uses "Dark all day" or "Light all day" when the sun never rises or sets. The parameter SUNANGLE was added to allow the definition of sun rise and set to be changed. Support for polar projection maps was added to the EGA/VGA version. It is not available in the MNO version. The response time for a key press during the generation of the next display frame was greatly decreased. Except during a fill operation on the polar projection maps, the response to a key press should be less than 0.3 seconds. A larger marker for the two fixed points in the distance function was incorporated, replacing the almost invisible symbols. H.8. Version 3.1 to 3.2 The accuracy of the sun position calculations was improved. It is now within about 5 minutes (time) in both latitude and longitude for the rest of the 20th century. Section G.1 gives details. The accuracy of the distance calculation was improved. Distances are calculated on a sphere with the same volume as the Earth, i.e., with radius 6371.22 kilometers. The control over latitude and longitude line placement was greatly enhanced with the addition of the GLINC, TLINC, GLSPEC, TLSPEC, and CLINE commands. See section C.2. The symbols used in the distance function now blink. The help system was completely revised. Pressing F1 or ? or "H" during GEOCLOCK display brings up a menu. Selecting a menu item brings up more detailed information. The REM command was added to allow users to document their GEOn.DAT files, and commands will be processed from GEOCLOCK.DAT and GEOn.DAT files in addition to GECONFIG.DAT. A bug that sometimes caused ZOOM and DISTANCE to ignore cities in the GEOn.DAT files was fixed. The GEOCONVT program was improved to allow map file conversions, control file deletion and GECONFIG.DAT processing from the command line, and another MCGA problem was fixed. The speed of the map conversion process was doubled. - 25 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 H.9. Version 3.2 to 3.3 The tab character is now treated as a space in the input files. The map select (S) function was added. The update interval (U) function was added. H.10. Version 3.3 to 3.4 The DRAWLINE, DRAWCIRCLE, and INCLUDE commands were added. All files are opened for read-only, so all files used by GEOCLOCK can have the READ-ONLY attribute. This simplifies the use of GEOCLOCK in networks. Command processing was changed so that the effects of commands in the GEOn.DAT files are local to MAPn. The speed of the "S" command was improved. The sun drawing system was changed so that the sun symbol is not displayed unless it is on the map being displayed. The ZONE commands are automatically updated when the year changes. The program assumes that the PC-s clock will remain in the time zone in effect at the time the program is started. H.11. Version 3.4 to 4.0 Support for the VGA 640x480 and SVGA 800x600 modes was added. This includes the NOSCR, SHOWVGA, VGA, and SVGA commands. The use of color was changed slightly to support these new modes. The sun symbol was changed to a color 5 symbol in the VGA and SVGA modes, and in EGA mode when NOSCR is specified. The NOSCR also solves the screen blinking problem found on some EGAs. An azimuth computation facility was added to the "D" function, as was the option of displaying coordinates in degrees and fractions. An option to sort the maps appearing in the "S" command was added. The sort used also determines in what order maps will be selected when using the "Zoom" function. The list of maps used by "S" and "Z" is written to a file, which greatly speeds up the first use of these functions. The INCLUDE function can be used as a "P" command. The Page-Up and Page-Down keys were added as synonyms for the left and right mouse buttons, and "Enter" was added as a synonym for the mouse center button. Mouse handling was changed so that the INT33 mouse driver does not have to specifically support VGA and 800x600 to use these modes. Any color can be used for city names, rather than just colors 5 and 7. Support of the polar projection maps was added to the MNO version. H.12. Version 4.0 to 4.1 This was primarily a maintenance release for GEOCLOCK 4.0. The FLICKER and NOBLINK directives were added to (I hope) finally end all the - 26 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 flicker problems. Also, an error in GEOCONVT.EXE was fixed that occasionally caused maps to be incorrectly converted. The SHOWSVGA directive was added, similar to SHOWVGA. The processing speed for long GE*.DAT and INCLUDE files was greatly improved. The accuracy of the terminator line with using the FAST directive (the default for systems without a co-processor) was improved. This is especially noticeable on small maps. The MAP directive was added to enable the map selection menu to be displayed when the program is first started. The MCOLOR directive was added to allow control over the color of the Markers with the distance function. I. Bulletin Board A free Remote Bulletin Board System (RBBS) provides support for users of the GEOCLOCK sunlight clock program. It always has the latest and untainted version of GEOCLOCK available for downloading. In addition, it provides a forum for all interested parties for program and information exchange concerning GEOCLOCK, high quality graphics for the IBM PC, high quality mapping for the IBM PC, and Turbo Pascal. Information on potential applications and needs is as important as information on techniques and software. The board is intended to help identify and solve real problems. Registered GEOCLOCK users have access to certain special files and higher access limits. Please have your registration number handy when you log on for the first time. Otherwise, the messages and files on the board are available to everyone. I also solicit comments and suggestions. I am especially interested in including position and phase data for the moon and perhaps other planets. The RBBS number is 703-241-7980. This is a Washington DC metro area number. J. Upgrades and Enhancements for Registered Users The GEOCLOCK bulletin board always has the latest version of GEOCLOCK, and a variety of extra map files and utilities available. In addition, many other bulletin boards and shareware distribution services also carry the latest version of GEOCLOCK. Registered users may obtain the latest version from any of these sources. When a new version is released, replace the files you originally received with the new versions. The REGISTER program, supplied on your distribution disks, must be rerun to enable the special features such as ZOOM and DISTANCE that are available only to registered users. If you have customized any of the GE*.DAT files, you may want to use the old versions of these files, or to edit the new versions to reflect your specific requirements. K. Registration and License - 27 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 The GEOCLOCK program is distributed as Shareware. This means that prospective users may use the program for a short evaluation period before deciding whether to purchase it. A license must be obtained to use any copy after this evaluation period. By sending $30 to the address below, a user will receive a single copy license, the latest version of the program, a registration program which will enable a few special features in the GEOCLOCK program not available in the evaluation version (see section E), a file with the name, latitude, and longitude of many world cities for building GEOCLOCK.DAT files, a "starter set" of GEO*.DAT files, and 28 maps. The prices for the GEOCLOCK program are: 1 copy $30 2-9 copies $25/license 10-20 copies $20/license 21-40 copies $15/license site license $600 for unlimited use at a single site. These prices assume that the purchaser will produce the authorized copies from a single master copy. GEOCLOCK is normally shipped on two 360K 5.25" floppy disks. It is available on a 720K 3.5" floppy disk for an additional $5.00. For an additional $20, a set of at least 15 supplemental maps will be included, and the next major release of the program will be mailed when it becomes available. All these items are available for downloading at no charge from the GEOCLOCK support RBBS. See section I. Please add $5.00 for shipping and handling for destinations outside the US and Canada. Cash or checks in US funds draw on US banks only. The file MAILER can be printed to give both a registration form and an envelope. Additional custom rectangular maps can be produced from my existing database for $30 per map. Simply specify the latitude and longitude of the center point, and the north to south distance on the map (the map will be scaled so that distances and azimuths are correct in the center of the map), or the latitude and longitudes of the corner points. Custom maps based on user supplied feature data or other projections (the GEOCLOCK program only uses flat rectangular and polar projections, but Lambert and perspective projections are available) are possible but must be negotiated on a case-by-case basis. - 28 - Joseph R. Ahlgren GEOCLOCK version 4.1 90/01/08 Maps included with registration: MAP1 World MAP2 48 States MAP3 Eastern US MAP4 SouthWestern US MAP5 Western Europe MAP6 Alaska MAP7 New York City Area MAP8 Finer Scale NYC MAP9 SouthEastern US MAP10 NorthWestern US MAP11 Chicago Area MAP12 Texas MAP13 Washington DC MAP14 Carolinas MAP15 Pennsylvania MAP16 New England MAP17 Central America MAP18 South America MAP19 Africa MAP20 Australia MAP21 India MAP22 Middle East MAP23 Micronesia MAP24 Japan MAP25 China MAP2000 North Polar Map MAP2001 North Polar Map 45 MAP2002 South Polar Map MAP4001 VGA world MAP4002 VGA 48 states MAP6149 SVGA world MAP6002 SVGA 48 states Maps included with optional supplemental disk: MAP26 North Central Europe MAP27 Western Europe MAP28 North Central Europe MAP30 San Francisco Area MAP31 USSR MAP32 North Atlantic MAP33 Scandinavia MAP34 Highlands and Islands MAP35 Southern California MAP37 Southern California MAP38 Sierra Nevada MAP54 Canada MAP71 The Aegean Sea MAP77 Silicon Valley MAP92 British Isles MAP100 Switzerland MAP104 Prince William Sound MAP131 Mexico MAP149 World Version 3 Joseph R. Ahlgren 2218 N. Tuckahoe St Arlington, VA 22205-1946 - 29 -