
Program SATGRAPH is an interactive shareware computer program for the IBM-PC
and true compatible computers which lets you quickly create orthographic and 
Mercator plots of a satellite's ground track, and true view images of the 
Earth as seen from a satellite. The program reads comma delimited ASCII data 
files containing the satellite's latitude, longitude and altitude as a 
function of time. The SATGRAPH software automatically detects the type of 
graphics display card in your system and supports HP compatible Laserjet (tm)
printers and Epson (tm) compatible dot matrix printers for hardcopy output. 
Graphic screens can also be saved to disk in PCX format. 

When you choose to select data or graphic files from disk the software will 
display a list of available files in a window. You can move around this list 
of files using the cursor keys or mouse, and select any file by pressing the 
Enter key or by double clicking with your left mouse button.

The following is the SATGRAPH main menu screen display:

-------------------------------------------------------------------------------
Browse  Graphics  DOS Shell  Printer  Quit
Load and interactively browse a data file.
-------------------------------------------------------------------------------

                               Program SATGRAPH
    
                   Satellite Mercator and Perspective Graphics
    
                          Written by C. David Eagle
    
                    Copyright (c) 1995 by Science Software
    
                            All Rights Reserved

                  This program uses data placed in the public
                    domain by F. Pospeschil and A. Riveria.
                  Original coordinate data created by the CIA.
------------------------------------------------------------------------------- 
<Move with left/right cursor keys or first letter>  <Enter=select>  <Esc=abort>
-------------------------------------------------------------------------------

The main menu options are located along the top line of this screen. The 
second line is a brief description of the corresponding menu item. The user 
can move between options by using the left and cursor arrow keys on the 
keyboard or by simply pressing the first letter of a program option. A program
option is selected by pressing the Enter key and you can exit from any program
option by pressing the Escape key.

The SATGRAPH main menu contains the following five program options:

Browse

This option lets the user select and interactively examine a disk data file. 
A file selection window will appear and the program will display the message

     Please select the data file to browse.

The keyboard arrow or cursor keys can be used to highlight the file of 
interest. Pressing the Enter key will recall the file and display it on the 
monitor screen. You can move around the data file by using the cursor, Home, 
End, PgUp and PgDn keys and leave at any time by pressing the Escape key. 

Graphics

This main menu option will display a submenu of graphic options. Many of the 
graphic options require the same type of information. The following is a 
description of necessary information and a discussion about how the user 
inputs it to the software.

The program will ask you to select a map data file to use when creating the 
requested graphic image. This map selection screen appears as follows:

     MWDB1.MAP
     MWDB2.MAP
     MWDB3.MAP
     MWDB4.MAP
     MWDB5.MAP

The MWDB1 map has the most detail and takes the longest time to plot, and the 
MWDB5 map has the least detail and plots the quickest. A map is selected by 
either scrolling up and down with the cursor keys or double clicking with your 
left mouse button. These map data files were created from information placed 
in the public domain by Fred Pospeschil and Antonio Riveria. This data was 
derived from the World Data Bank II produced by the CIA.

The SATGRAPH software will also ask you which geographic features to include 
on the map display. This multiple selection prompt screen includes 
instructions and appears as follows:

     Please select the map features to plot. Use the cursor keys
     or mouse to move between features. Select or deselect features
     with the Enter key or left mouse button. Continue with the Esc
     key or double click the right mouse button

          Coastlines
          Country borders
          State borders
          Islands
          Lakes
          Rivers
          All features

The program will also ask you to select a latitude/longitude/altitude data 
file to use. This is accommodated by way of a file selection screen. Please 
note the scroll up/down arrows and slider on the right side of the screen.

Once a valid file has been selected, the software will ask you to input the 
time interval between automatic graphic screen updates with this next prompt:

  Please input the time interval between screen displays (seconds) 60

Notice that the program default is 60 seconds unless you change it.

You can also specify the interval in degrees for plotting lines of constant 
latitude and longitude on an SATGRAPH map display by responding to the next 
two requests:

        Please input the latitude lines plot interval (degrees) 30

        Please input the longitude lines plot interval (degrees) 30

The software will also allow you to plot a subset of the data. The user 
prompt for this program option is as follows:

        Would you like to plot a subset of this data (Y/N)? N

Simply press Y or N in response to this request. If you choose to plot a data 
subset, the SATGRAPH program will ask for the initial and final simulation 
times by displaying the next two prompts:

        Please input the initial time (days)

        Please input the final time (days)

Please note that the initial time must be positive or zero and that the final 
time must be greater than the initial time. The time inputs can include 
fractional days.

If you create orthographic or Mercator graphics, SATGRAPH will ask you for the 
type of line type to use for plotting geographic features, ground tracks and 
coverage circles with the following prompt:

        Please input the line type for the plot (L = line, P = pixel) P

The software will also ask if you would like to display coverage circles by 
displaying

        Would you like to plot coverage circles (Y/N)? N

If your response to this question is yes, the program will ask for the minimum 
topocentric elevation angle to use with the next prompt:

        Please input the elevation angle (degrees) 0

Coverage circles are the instantaneous areas of the Earth visible from the 
spacecraft subject to any user-defined elevation angle constraint.

Finally, SATGRAPH will ask if you would like to manually single step the 
graphic displays with

        Would you like to single step the graphic displays (Y/N)? N

To advance to the next screen after an image has been completely displayed, 
press the C key. To leave a graphics screen option at any time press the E 
key, to print any graphic screen to the printer defined in the PRINTER.DAT 
file or manually set up by the user, press the P key, and to save the screen 
to a PCX disk file press the S key. At any time during the plotting of the 
world map, you can press the Escape key to prematurely terminate the activity 
and return to the main menu.

The following is a list and brief description of each type of graphic display 
option.

Orthographic

This graphic menu option creates a view of the Earth and spacecraft ground 
track from a very far distance in space. SATGRAPH will ask you to input the 
geographic latitude and longitude of the viewpoint with the following screen 
menus:
-------------------------------------------------------------------------------
              Please input the viewpoint geographic latitude
    
          (degrees [-90 to +90], minutes [0-60], seconds [0-60])
    (NOTE: north latitudes are positive, south latitudes are negative)
     
                           + 00 d 00 m 00 s

             Please input the viewpoint geographic longitude
         (degrees [-360 to +360], minutes [0-60], seconds [0-60])
    (NOTE: East longitude are positive - west longitudes are negative)

                             + 000 d 00 m 00 s

         < Move with left/right cursor keys - [Enter] = select >
-------------------------------------------------------------------------------

True View

This program option will create a view of the Earth as seen from the 
satellite's altitude. The view is towards the center of the Earth in a nadir 
direction directly below the satellite.

Mercator

This program option creates a Mercator display of the Earth and the 
satellite's ground track. Coverage circles are also displayed if the user has 
selected them.

View

This main menu option displays a list of PCX disk files, lets the user select 
one and displays it on his or her monitor screen. Once the graphic image 
appears, you can print it to the printer defined in the PRINTER.DAT file by 
pressing the letter p on the keyboard. This program option shells to a 
utility program called VIEWPCX. This utility displays a window of PCX files 
and lets the user select one. After a graphic image appears, you can print the 
screen to the printer defined manually by the user or using the information in 
the PRINTER.DAT file.

Filename

This main menu option lets you input a file name for saving PCX graphic 
images. If you do not manually specify a file name to use, the program 
defaults to the filename SATGRPH plus an integer.

-------------------------------------------------------------------------------
     Please input a filename for the graphics data file. This name
    should be no more than seven characters long. Do NOT include a
    filename extension. A sequential number and filename extension
     of .PCX will be automatically appended during the file save
     process. To save the graphics image to disk, press the S key
           after it is completely displayed on the screen.
    
       Please press the Enter key when finished or the Esc key
                       to leave this selection.
          
    Please enter a filename
-------------------------------------------------------------------------------

Calibrate

This program option lets you manually adjust the rectangular and circular 
aspect ratios for your hardware. Simply follow the instructions which appear 
on the screen. A ruler is required during the rectangular calibration 
procedure.

After the calibration is complete, the program will ask if you would like to 
save the results to a simple ASCII file in the current directory with the 
following prompt:

        Would you like to write the calibration results to the file
       SATGRAPH.CAL? These values will be used in all future graphics
          options. They can be changed again later if necessary.

       Save results to SATGRAPH.CAL (Y/N) Y

If you elect to save the results to this calibration file, SATGRAPH will 
automatically read it each time you run the program. The SATGRAPH.CAL file 
must be in the current directory.

DOS Shell

This program option invokes a DOS shell from within program SATGRAPH. You can 
return to SATGRAPH at any time by simply typing the word EXIT at the DOS 
prompt.

Printer

This program option lets the user set up his or her printer. Please note that 
this must be done prior to printing any graphic images. The following is a 
brief review which describes how to configure your printer for proper 
operation with SATGRAPH.

The print orientation is selected by pressing either 1 or 2 in response to the 
following request:

                   Please indicate the print orientation.

                      1 = portrait       2 = landscape

The type of printer is selected by pressing either the D or L key in response 
to the following program prompt:

             Please indicate the type of printer you are using.
         Press the D key for an Epson compatable dot matrix printer
        or the L key for an HP compatible Series II LaserJet printer.

                       D)ot matrix          L)aserJet

The SATGRAPH software assumes that your printer communicates using a parallel 
port interface. The parallel port to which your printer is attached is 
selected with the proper response to this next request:

            Please indicate the parallel port your printer uses.

                   1 = LPT1       2 = LPT2       3 = LPT3

If a LaserJet has been selected, the program will ask for the print resolution 
with the next prompt:

           Please indicate the print resolution in dots per inch.

         1 = 75 DPI     2 = 100 DPI     3 = 150 DPI     4 = 300 DPI

If it exists, SATGRAPH will also automatically read a simple ASCII data file 
of printer parameters. This file must be named PRINTER.DAT and it must be 
located in the same directory as SATGRAPH. The following is a typical example 
of the information contained in this file. Do not add or delete any lines 
from this file. Simply modify the integer numbers for your printer and port 
configuration if necessary.

This simple data file defines the printer type, parallel port, print 
orientation and for LaserJets, the print resolution. If you set up this file 
it is not necessary to manually set the printer characteristics. The following
is a typical SATGRAPH printer data file:

**********************************
*** SATGRAPH Printer Data File ***
**********************************

PRINTING OPTIONS

Type of printer (1 = Epson, 2 = HP Laserjet)
2

Printer parallel port (1 = LPT1, 2 = LPT2, 3 = LPT3)
1

Laserjet printer resolution (1 = 75 DPI, 2 = 100 DPI, 3 = 150 DPI, 4 = 300 DPI)
3

Laserjet printer orientation (1 = portrait mode, 2 = landscape mode)
1

Quit

This final option completely exits program SATGRAPH and return to DOS or 
Windows (tm).

*****************************************************************************

SATGRAPH Latitude, Longitude and Altitude Files

This section describes the required format for ASCII data files which are read 
and plotted by SATGRAPH. These files contain four columns of comma delimited 
data and MUST have a file name extension of LLA.

The first column is the elapsed simulation time in days. The second column 
contains the latitude of the satellite's subpoint in degrees. Latitude must be
between -90 and +90 degrees. The third column is the east longitude of the 
satellite's subpoint, also in degrees. East longitude must be between 0 and 
360 degrees. The fourth and final column contains the altitude of the 
satellite in the units of kilometers. Please note that the SATGRAPH software
reads this data as double precision numbers.

The following is part of a typical SATGRAPH compatible data file.

   0.0000,   0.00, 259.82,     350.00
   0.0007,   1.97, 262.98,     349.98
   0.0014,   3.92, 266.14,     349.91
   0.0021,   5.87, 269.32,     349.79
   0.0028,   7.79, 272.53,     349.63
   0.0035,   9.69, 275.76,     349.43
   0.0042,  11.55, 279.04,     349.18
   0.0049,  13.36, 282.36,     348.90
   0.0056,  15.13, 285.74,     348.57
   0.0063,  16.83, 289.18,     348.21
   0.0069,  18.47, 292.68,     347.82
   0.0076,  20.04, 296.25,     347.39
   0.0083,  21.52, 299.90,     346.94
   0.0090,  22.91, 303.63,     346.46
   0.0097,  24.19, 307.44,     345.95

You can also manually create a SATGRAPH data file for special applications. 
For example, the following single line data file can be used to create a true 
view of the Earth centered over Denver, Colorado from an altitude of 350 km.

   0.0000,  39.75, 284.00,     350.00

***********************
VIEWPCX UTILITY PROGRAM
***********************

The SATGRAPH distribution disk also contains a utility program called VIEWPCX
which can be used to view and print several PCX images captured from the 
SATGRAPH program. To use this utility simply type VIEWPCX at the DOS command 
line. The program will display a menu of file names with a .PCX extension and
you can select one using the mouse.

If it exists, VIEWPCX will also automatically read a simple ASCII data file 
of printer parameters. This file must be named PRINTER.DAT and it must be 
located in the same directory as VIEWPCX. The following is a typical example 
of the information contained in this file. Do not add or delete any lines 
from this file. Simply modify the integer numbers for your printer and port 
configuration if necessary.

This simple data file defines the printer type, parallel port, print 
orientation and for LaserJets, the print resolution. If you set up this file 
it is not necessary to manually set the printer characteristics. The following
is a typical VIEWPCX printer data file:

**********************************
*** VIEWPCX Printer Data File ***
**********************************

PRINTING OPTIONS

Type of printer (1 = Epson, 2 = HP Laserjet)
2

Printer parallel port (1 = LPT1, 2 = LPT2, 3 = LPT3)
1

Laserjet printer resolution (1 = 75 DPI, 2 = 100 DPI, 3 = 150 DPI, 4 = 300 DPI)
3

Laserjet printer orientation (1 = portrait mode, 2 = landscape mode)
1

A PCX screen can be printed by pressing the P key after the complete image is
displayed on your monitor screen. The VIEWPCX program is exited by pressing 
the Enter key after printing or viewing the image.

-----------------------------------------------------------------------------

A complete set of world maps for program SATGRAPH is available for $20 ($25
outside the United States). These map files (MWDB1, MWDB2, MWDB3, MWDB4 and
MWDB5) are supplied on 3.5" high density floppy disks.

Please address all technical questions, correspondence and orders to:

     C. David Eagle
     P.O. Box 621022
     Littleton, CO  80162-1022

     (303) 904-2528

     Compuserve   74561,606

     Internet     74561.606@compuserve.com
