











			     T O P O  

	     The 3-D Topographic Map Plotting Program
			   Version 3.0


		  (c) 1993 by Donald A. Burrows



			   User Manual










































INTRODUCTION

	This program began as a long time dream to be able to put 
topographic maps in to my computer so that I could view any region at any 
scale and from any point of view I desired. It developed as a fairly flexible 
program that allows one to depict the data not only as more or less 
traditional colored contour maps (Conic Projection) but also as 3-D oblique 
views both with color contours and gray-scale shaded relief surfaces.

	The program is designed to be used in the either 16 or 256 color 
modes. Two different 256 color modes are implemented, a non-standard 
360x480x256 mode which will work on most IBM compatible VGA cards and the 
standard MCGA 320x200x256. In addition 3, 16 color modes are available, 
the VGA 640x480x16 mode, as well as the EGA 640x350x16 and 640x200x16 modes. 
While it will run without a math co-processor, it is highly recommended to 
have one as otherwise the plotting procedure can be incredibly slow. It's 
performance on an 12 mHz AT with a math co-processor is adequate, but it 
runs very nicely on 33MHz 486 machine. The program was intended to be used 
on a hard disk with the topographic data files on floppy diskettes; however, 
it can be run with both program and data on floppys or both on the hard disk.

	The program is designed to work with the 30-second topographic 
database for the United States and TOPO30 software which can be obtained 
from

		U.S. Department of Commerce
		National Oceanic and Atmospheric Administration
		National Geophysical Data Center
		325 Broadway  E/GC1
		Boulder, CO 80303
		ph (303) 497-6764
		fax (303) 497-6513

	To use the TOPO30 program to obtain files which can be used with TOPO 
it is necessary to select undelimited elevations for the output file format 
and to select meters as the elevation units. In addition to the data file 
the program also generates an information file marked by the extension .INF 
which must also be present with the data file in order to read the data into 
TOPO.



GETTING STARTED
	This section is for those who want to learn the program by doing. 
Examples will be given showing how to produce several different types of 
maps. To start follow the directions on the Readme.txt file on the program 
diskette. If all goes well the following files should be together in the 
same directory. 
		
		TOP.BAT
		TOPO.EXE
		GETMODE.EXE
		MHR.SCN
		VGA.SCN
		MCGA.SCN
		EGA.SCN
		SCD.SCN
		NEWYORK.T30
		NEWYORK.INF
	
	If it is assumed that all the files are on the C drive in a directory 
named TOPO, the program can then be started by entering

C:\TOPO > TOP

If the program files were on the C drive in dirrectory TOPO and the data 
files were on floppy diskettes in drive A, then the program could be 
initiated by entering

C:\TOPO> TOP A:

	You will be given the choice of selecting the graphics mode you want 
to use. There are 3, 16-color modes and 3, 256-color modes available. The 
16-color modes allow the plotting of maps either as color contour maps or as 
grayscale shaded relief maps, while in the 256-color format all maps depict 
both color contours and shaded relief. The 360x480 mode is a non-standard 
mode but will work on most VGA adapters and provides a significant 
improvement in resolution over the MCGA 320x200 mode.

	Once the program screen is displayed, then menu selections can be 
made by either using a mouse and the left mouse button or by the use of the 
arrow and <Enter> keys. Menu boxes can be exited by using the <Esc> key. 
When it is necessary to enter a number or file name from the keyboard, the 
<Insert> key is used to initiate the editing process. After entering the new 
value a <Enter> is required. To exit the box there are two possibilities. 
The <Esc> key is used to exit without updating the values and <F2> is used 
to exit and save the new values. Note: the mouse will not work in the 
360x480,  256 color mode.


DISPLAYING AND CREATING MAPS

	There is one data file  provided with TOPO. This can be loaded and 
viewed and used to create new maps. Start by loading the data file. This 
contains the elevation data for a given region that is necessary in order to 
draw any map with TOPO. No map can be created or redrawn without having a 
data file loaded into memory. To load the data file begin by using the arrow 
and <Enter> keys or mouse pointer and left mouse button to select DISPLAY 
followed by LOAD DATA FILE. To enter the file name press <Insert>, then type 
NEWYORK.T30 followed by <Enter>.

	If all is working well you should see the message

		   <DATA LOADING - PLEASE WAIT!>
		       116644 bytes required

If the data file is too large for the available memory the message 
"Insufficient Memory" will be displayed in the bar at the bottom of the 
screen.

	Start by creating a map showing the contents of the entire 
data file. First select [Type] and [2-D Map]. This specifies a two 
dimensional conic projection map with standard parallels at 35 and 43 degrees 
North.
	
	Next select the base elevation and contour interval appropriate for 
the region. Elevations less than the base elevation are not plotted. The 
contour interval determines the range of elevation over which each color is 
used. In the 256 color modes there are 11 different colors with 22 shades of 
each used in addition to the background color. In the 16 color modes there 
are 15 different colors in addition to the background color. For the New York 
file a base elevation of 0 feet corresponds to the lowest elevation in the 
file.  Since the highest elevation in the file is less than 2000 feet a 
contour interval of 150 feet is good for the 256 color modes. In this case 
any elevation over 10x150 + 0 = 1500 feet will be shown as shades of gray. 
If a contour interval of 100 feet of is used in a 16 color mode, then any 
elevation over 14x120 + 00 = 1680 feet will be white. Select  [Options] and 
[Set Contours], push <Insert> and enter the base elevation followed by 
<Enter>. Push <Insert> again and enter the contour interval followed by 
<Enter> . If the values have been entered correctly then push <F2> to update 
to the new values. If <Esc> is pushed then the menu is exited without 
updating the contour values. Finally to start the plot select [Display] and 
[Clear Screen] then [Display] and [Display New Map].

	The computer should should be starting to plot a color contour map 
viewed from directly overhead at a distance that will allow the entire data 
region to be displayed on the screen. Pressing any key during the plotting 
will cause the program to stop at the end of the current line. Be careful 
when you do this however as the program will have to plot all over from the 
beginning if you restart with [Display] and [Display New Map].

	At any time when the menu selector bar is visible, the screen 
display and the current map selection data can be saved in a disk file by 
selecting [Display] and [Save Map Display]. The display is saved in a file 
with the name MAPFILxx.PCX, where xx represents two digits starting with 00 
for the first file in the directory and going up to 99.

If it is desired to determine the values of the various map parameters 
associated with it, one need only select the menu choice connected with it 
and the current value will be displayed. For instance if it is desired to 
determine the contour interval of the loaded map select [Options] and 
[Set Contours]. The box should indicate the base elevation  and the contour 
interval. The <Esc> key can be used to exit without altering the values.

	If at this point you select [Display] and [Clear Screen] then 
[Display] and [Display New Map] the previous map will be redrawn since all 
the map parameters necessary to re-create the map were loaded with the map 
file. A MAP CAN ONLY BE DRAWN AFTER A DATA FILE HAS BEEN LOADED. 

	A three-dimensional, oblique  view of the New York area can be 
created by selecting  [Display], [Set New Region] and then entering and 
changing the northern boundary to 41.5 degrees, the western boundary to 
74.35 degrees and the eastern boundary to 73.15 degrees. Press <F2> to 
update the changes. Then select [Type], [3-D Map], [Options], [Viewpoint]. 
Change the vertical angle to 75 degrees and the distance to 50 miles and 
update by pressing <F2>. Next select [Options], [Set Solar Angle]  and 
change the azimuth angle to 120 degrees. Now select [Display] and [Display 
New Map], the computer should then start drawing the new view. When complete 
this view can be saved as well if desired.

DESCRIPTION OF MENU OPTIONS

DISPLAY - Under this heading the screen can be cleared, a data file loaded, 
a current selection plotted, a new map region can be specified, a newly 
drawn map saved, or a completed map viewed.

CLEAR SCREEN - This removes any currently displayed images from the screen. 
In the black and white mode it can also be used to replace a black 
background with a white background.

LOAD DATA FILE - This will load a data file created by the TOPO30 program  
using Undelimited Elevations for the output file format with the  units in 
meters. If the file is too large to be loaded into available memory the 
message "Insufficient Memory" will be displayed. The program at present does 
not utilize extended or expanded memory and so is limited to the DOS 640K 
memory. If the computer has at least 640K of DOS memory available with no 
large TSR programs resident such as network programs then files covering up 
to about 4.5 square degrees can be accomodated. A file as it is loaded 
displays the amount of memory required to store it which is less than the 
size of the file on the disk. 
	It is not recommended to run TOPO under Windows as not only does it 
take up memory but also it interferes with the fonts for two of the 256 
color modes.

	Note: Whenever TOPO30 is used to create a datafile it leaves a 
memory resident program behind of about 50 Kbytes. This will limit the 
maximum size of a data file that can be loaded into TOPO. If you get an 
insufficient memory message when trying to load a file after using TOPO30, 
you may be able to correct the condition simply by rebooting and trying 
again.

DISPLAY NEW MAP - This causes a map to be plotted using the currently
specified map parameters.


SET NEW REGION - Under this heading the northern, southern, western and
eastern boundaries of a region to be plotted can be specified. The units
are degrees and decimal fractions of degrees. North latitude and West
longitude are positive values.

SAVE MAP DISPLAY - This is used to save completed maps using the ZSoft
PCX format. Files are automatically named beginning with MAPFIL00.PCX
up through MAPFIL99.PCX. Files are stored in the directory that the program 
is located in.

LOAD MAP DISPLAY - This is for viewing saved maps. Enter the complete file 
name including extension. Looks for file only in the same directory as the 
program is located unless a path is included with the name. 

TYPE - Under this heading the the type of map can be selected, i.e. contour 
or shaded, 2-D or 3-D.

SHADED (B/W) - This appears only in 16 color modes and specifies a black and
white shaded relief type plot. If a black background is desired choose [Clear 
Screen] before selecting [Shaded (B/W)]. If a white background is desired 
then choose [Clear Screen] after selecting [Shaded (B/W)]. This also 
specifies a high contrast mode. A lower contrast mode can be obtained by 
selecting [Alt Palette] under [Features].

COLOR CONTOUR - This appears only in 16 color modes and specifies a plot 
using the color contour mode. It  also specifies a blue background. Using 
[Color Contour] and [Alt Palette] one can toggle back and forth between a 
white background and a blue background.

In the 256 color modes all maps use both color contours and shading.

3-D MAP - Draws a map viewing a spherical earth whose topography can be 
magnified. Adjacent 3-D maps will not quite fit together to make a larger 
map.

2-D MAP - Shows the projection of a spherical earth onto a smooth conical 
surface. The cone's point is above the North Pole and the surface of the 
cone intersects the earth's surface at latitude 43 degrees North and 
latitude 35 degrees North. The edges of adjacent maps can be made to fit 
together so that in theory at least, one could print out several smaller 
maps and fit them together to make a larger map.

ABOUT TOPO - Displays version, author and copyright date.


OPTIONS - Under this heading a number of different plotting options can
be specified, such as selecting an alternate color palette, setting the
point from which the map is to be viewed, setting the contour interval,
setting the direction of the lighting and drawing a lat-lon grid over the 
map.

ALT PALETTE - In color contour mode this specifies a palette with a white 
background and a pink max contour color. In black and white mode it specifies 
a high contrast gray scale with only black, white and a medium gray. A 
different set of colors is available for the 256 color palette as well.

SET VIEWPOINT - This is used to specify the placement of the observer 
relative to the map. The default azimuth angle is 0 degrees which places 
north at the top of the map. 90 would place east at the top, 180 - south, 
and 270 - west. The default vertical angle is 0 degrees which indicates that 
the map is being viewed from directly overhead. 90 degrees in this case would 
mean that the observer would be looking at the map horizontaly from sea-
level. Distance is specified in miles from a point at sea-level located 
horizontally in the center of the map. The default value is 155 miles which 
is a good value for observing a 1 degree by 1 degree region from directly 
overhead. Entering a distance of 0, will cause the program to autoscale to 
fit the selected region on the screen assuming that both azimuth angle and 
vertical angles are also 0.

SET CONTOURS - This option is used to specify the altitude from which color
contours are computed and the altitude interval between successive colors. 
In the 16 color mode there are 15 altitude intervals. If the base elevation 
is 0 (sea-level) and the contour interval is 500 ft. then the background 
(blue or white) color will indicate all regions of altitude 0; the dark 
green, altitude 0 to 500; up to white or pink for all regions over 7000 ft. 
The default value of the base elevation is 0, and the default value for the 
contour interval is 500 ft. Note: In the topographic data files the 
elevations are specified to only the nearest 20 feet above sea level, 
consequently areas that are less than 10 feet above sea level have 
apparently been rounded off to 0 so that they will be displayed as ocean 
instead of being displayed as land. As a result many low lying coastal areas 
may not appear at all.

  The order of the color contours in the 16 color modes is as follows:

			Sea Blue / White
			Dark Green
			Green
			Light Green
			Dark Yellow-Green
			Light Yellow-Green
			Yellow
			Brown
			Dark Brown
			Tan
			Orange
			Dark Gray
			Light Gray
			Light Tan
			Light Olive
			White / Pink

The colors after the / are the colors found on the alternate palette.

	For the 256 color modes the order of the color contours is:

	Reg. Palette                    Alt. Palette
	
	Blue                            Azure
	Lt. Cyan                        Bluish-Green
	Bluish-Green                    Lt. Bluish-Green
	Green                           Green
	Lt. Green                       Yellowish Green
	Yellowish-Green                 Greenish-Yellow
	Greenish-Yellow                 Yellow
	Yellow                          Yellow-Brown
	Lt. Yellow                      Brown
	Lt. Tan                         Reddish-Tan
	Tan                             Tan
	Gray                            Gray

SET SOLAR ANGLE - This applies to the shaded mode and determines the 
direction of the lighting relative to the earth. A solar azimuth angle of 0 
has the lighting coming from the north, while a value of 90 will have it 
coming from the east, 180, from the south and 270, from the west. Solar 
height determines the vertical angle from which the lighting will come. In 
this case 0 degrees would indicate the sun is on the horizon of the map and 
90 would place it directly overhead. Default values are: Solar Azimuth - 240 
degrees and Solar Height 34 degrees.

MAGNIFY - This allows the vertical scale of the maps to be enhanced. It has 
no effect of the contour display. Selecting x1 means that there is no 
vertical exageration i.e. the vertical scale is the same as the horizontal 
scale. Five different vertical magnifications can be selected. 1.5 times 
normal, 2 times normal, 3 times normal, 5 times normal and 10 times normal.

QUIT - This exits the program. Pressing <Alt-X > has the same effect.


TO REGISTER

You are urged to register your copy of TOPO by sending $25 to 

	Donald A. Burrows
	526 Belmont Rd.
	Grand Forks, ND 58201

	Phone: (701) 775-3523

	EMail:  GENIE:  D.BURROWS2
		INTERNET: BURROWS@VM1.NODAK.EDU

You will receive a copy of the latest update of TOPO which includes support 
for SVGA, the ability to create index maps for data files, the ability to 
draw lat-lon grid lines on a map and other improvements.


KNOWN BUGS

The major known bug in version 3.0 occurs only in the 320x200x256 MCGA mode. 
The menu selector bar for the secondary menus either does not appear or 
disappears after certain selections are made. Consequently this mode does not work 
well without a mouse. This is an inferior mode anyway and the problem does not 
occur in any of the modes with better resolution.


ACKNOWLEDGEMENTS

	Thanks are due to John Bridges for his VGAKIT version 5.2 making it 
possible to utilize the nonstandard 360x480x256 graphics mode.

	The PCX graphics format was developed by the ZSoft Corp. for use with 
their PC Paintbrush and Paintbrush Plus. The version of the PCX format used is 
supposed to be compatible with versions 3.0 or greater.



--------------------IMPORTANT -- WARRANTY & DISCLAIMER -----------------

TOPO version 3.0 is shareware and you are urged to register. It may be
freely distributed provided all the files in TOPOV300.ZIP are included. 
The author makes NO warranties, expressed or implied as to the quality or 
the performance of this program. The author will NOT be held liable for any 
direct, indirect, incidental or consequential damage resulting from the use 
of this program. Your use of this program constitutes your agreement to this 
disclaimer and your release of the author from any form of liability or 
litigation.
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