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Shareware Extravaganza - Disc 4
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Shareware Extravaganza - Over 25,000 Programs (The Ultimate Shareware Company)(Disc 4 of 4)(1993).iso
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latlon.zip
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LATLON.DOC
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1990-11-08
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┌───────────────────────────────┐
│ ABOUT THE CONVERSION SOFTWARE │
└───────────────────────────────┘
This software is designed for those people who would like to
convert known latitude and longitude coordinates into X and Y
coordinates for plotting in AutoCAD or any other CAD program that
will accept DXF input files.
The user has the ability to define a Central Meridian and base
parallel as an initial starting point from which all X and Y
coordinates will be set. The user may also add an easting and
northing value to the calculated X and Y coordinates so that
negative X and Y values can be eliminated.
It is suggested that the Central Meridian and the base parallel
be set to the approximate center of the area you are mapping. The
further the input latitude and longitude values are from the
central meridian and base parallel the more distortion there will
be in the mapping of the points. The software reports a scale or
distortion factor for each converted point so that the user can
monitor.
The software converts the latitude and longitude to X and Y
coordinates by using a Transverse Mercator projection Algorithm
developed by the U.S. Geological Survey and printed in Geological
Survey Bulletin 1532.
Transverse Mercator projections are made by placing a transverse
cylinder around the earth. In effect, a light source at the
center of the earth is used to project locations on the earth
onto a map much like a slide projector projects an image onto a
screen.
The program is set up to use a Clarke 1866 Spheroid as an earth
model for developing constant values in the transverse Mercator
projection. This spheroid model is normally used for projections
centered on North America.
┌──────────────────────────────────────┐
│ PROGRAM CONFIGURATION AND DATA INPUT │
└──────────────────────────────────────┘
ALL INPUT OF LATITUDE AND LONGITUDE MUST BE IN THE FOLLOWING
FORMAT.
xxxDxxx'xxx"
degrees value must be followed by the letter D or d or +
minutes value must be followed by the '
seconds value must be followed by the "
example input would be:
100D15'24"
88d10'
15D25'.5"
-80d5'25" *
50+10'25"
15D10.5'
* YOU ONLY ENTER A NEGATIVE LATITUDE OR LONGITUDE VALUE IN THE
SETUP CONFIGURATION FILE. Input of latitude and longitude values
for conversion to X and Y values are ALWAYS entered without the
positive or negative sign. The negative sign in the configuration
file would tell the software to consider entered values for
conversion to be negative.
To start the program enter the command LATLON.
You have three choices in the main menu.
1) Convert Latitude and Longitude to X Y
2) Change setup configuration values
3) Quit
┌─────────────────────────────────────────────────────┐
│ CONVERTING LATITUDE AND LONGITUDE TO X AND Y VALUES │
└─────────────────────────────────────────────────────┘
To convert latitude and longitude to X and Y values press the 'L'
key at the main menu.
You will first be prompted for a note input for the point. This
text will be printed next to the point when it is input into a
CAD drawing. You may just press <<return>> if you no do wish to
include a note.
You will then be asked for the Latitude and longitude for the
point.
The conversion software will calculate the coordinates, apply any
easting or northing values and then display the X and Y
coordinates. A calculated scale factor will also be displayed.
The scale value is for your information only. The closer the
value is to 1 the more accurate you know the X and Y coordinate
values are. The further the input latitude and longitude are from
your central meridian, the greater the distortion/scale factor
will be.
Registered software users will receive a version of the
conversion program that allows user input of a scaling factor to
adjust for large distortions when mapping a large area.
┌────────────────────────────┐
│ CREATING A DXF OUTPUT FILE │
└────────────────────────────┘
The software will automatically create a DXF output file of the
converted points and notes if you have selected that option in
the setup configuration file.
If you have chosen that option in your setup, a DXF output file
will be created with the name LATLON.DXF
All latitude and longitude data converted during a session with
the software will be input into the same DXF file. Once you exit
or Quit from the main menu, the file is saved.
WARNING!!
If you wish to enter the conversion program again the file
LATLON.DXF will be REPLACED by new data. If you wish to keep the
DXF file you just created, use your DOS commands to rename the
file to a new file name with the .DXF extension to prevent
erasing it.
The DXF file can be input into AutoCAD and many other CAD
programs to generate an accurate drawing or map of the latitude
and longitude coordinates.
Consult the CAD program instructions for input of a DXF file.
┌───────────────────────────┐
│ SETUP CONFIGURATION FILE │
└───────────────────────────┘
The software reads an ASCI text file name "LATLON.CFG"
The file LATLON.CFG contains basic setup information for the
software to use in calculating X and Y coordinates and for
creating the DXF output file.
A sample LATLON.CFG file is as follows.
Each line contains one setup value.
-100D *
40D
FEET
0
0
Y
2
The first line in the file is the Central meridian (longitude) to
use as an initial X coordinate value of 0. If the central
meridian you select is West of the Prime Meridian (which runs
thru England) you must enter then longitude as a negative value.
If the central meridian is East of the Prime meridian, you enter
the longitude as positive.
* YOU ONLY ENTER A NEGATIVE LATITUDE OR LONGITUDE VALUE IN THE
SETUP CONFIGURATION FILE. Input of latitude and longitude values
for conversion to X and Y values are ALWAYS entered without the
positive or negative sign. The negative sign in the configuration
file would tell the software to consider entered values for
conversion to be negative.
The second line is the base parallel (latitude) to use as an
initial Y coordinate value of 0. If the base parallel is north of
the equator the latitude is positive. If the base parallel is
south of the equator then the latitude must be entered as a
negative value.
The third line in the configuration file is the default UNITS to
use in conversion. Units may be in METERS, FEET or MILES. A
conversion factor is applied to all calculated X and Y
coordinates based on the units you select.
The fourth line is an easting or 'X' value to add to the
calculated X coordinate.
Line 5 is a northing or 'Y' value to add to the calculated Y
coordinate.
By adding an easting or northing value to the calculated X and Y
coordinates, you can avoid getting negative coordinates. This may
be desirable once the points are input into a CAD program. The
location of points relative to each other is not affected by the
easting and northing values.
Line 6 tells the software whether you want to create a DXF output
file of the calculated X and Y coordinates. A simple Y or N is
required.
Line 7 is the height for notes in the DXF file. This value must
be entered even if you say No to creation of a DXF output file.
To change any of these setup configuration values choose that
option from the main menu by pressing the letter C. You will be
asked for input on each of the options and a new configuration
file will be created to reflect your choices. A default
configuration file equal to the sample in this documentation file
is included with this package. The configuration file must be
present on the disk or in the same sub-directory as the main
program.
┌────────────┐
│ SHAREWARE │
└────────────┘
This conversion software is being distributed as shareware.
If you receive a copy of the software and use it, use should
register it.
Registered users will receive a current copy of the software that
includes additional features. Additional features include being
able to select various spheroid models of the earth for more
accurate mapping of various portions of the globe as well as
input of a scaling value to evenly balance distortion across a
mapping area.
Updated versions of the software will include inverse conversion
of X and Y values to latitude and longitude and additional
projection algorithms.
Users should send a registration fee of $20 to:
TDM Software
Terry Majewski
3620 L Street
Lincoln, NE. 68510
Comments and criticism and always welcome.