MADTRAN User's Guide and Download Instructions

National Imagery and Mapping Agency

Table of Contents

• INTRODUCTION
• INSTALLATION
  • PC Platform

• STARTING INSTRUCTIONS
• PROGRAM OPERATING INSTRUCTIONS
  • Starting Screens
  • Output Device
  • GP Format
  • Direction
  • Input Type
  • Local Datum
  • Geodetic Position
  • UTM Grid
  • MGRS Grid
  • Error Trapping
  • Results Screen

• KNOWN BUGS
• LIMITATIONS
• REFERENCES
• PROGRAMMING NOTE

• MADTRAN SOFTWARE DOWNLOAD INSTRUCTIONS

INTRODUCTION

NIMA has developed a global coordinate system (datum), the World Geodetic System 1984 (WGS 84), upon which to base all Mapping, Charting, and Geodetic (MC&G) products. This program transforms between local geodetic datums and WGS 84 (from the local datum to WGS 84 and vice versa). Coordinates may be input in any of three standard formats: geodetic position (GP), Universal Transverse Mercator grid (UTM), or Military Grid Reference System (MGRS). Coordinate conversion will be done if possible on both the input point and the transformed point, so that each will be displayed in all three formats. This program is designed for coordinates scaled from maps and charts.

INSTALLATION

PC Platform

The program will run more quickly if it is copied to and run from the hard disk.
The files "ellips.dat" and "datum.dat" should be in the same directory as "madtran.exe" after the expansion.

STARTING INSTRUCTIONS

If you are familiar with datum transformation standard coordinate formats you should be able to begin experimenting with the program

1. The first two screens are informational. If the user wishes to read the documentation and configuration management information, type "F1".
2. The user will next select the Output Device, the GP Format, the Transformation Direction and the Input Coordinates.
3. Chose the Local Datum, the program will transform between a Local Datum and WGS84. If a transformation between two Local Datums is desired it must be done "through" WGS84.

PROGRAM OPERATING DIRECTIONS

Starting Screens

The two initial screens are informational. They also provide access to the Help and Configuration Management information for MADTRAN. To access this information, press the "F1" function key.

Output Device

Choose from:

• Video display only, or
• Text File plus video

The Video Only choice displays results only on the screen, so any values you wish to save must be hand recorded.

When Text File is the Output Device choice, output will be written to a text file named by the user in the same directory as the executable.

If you leave it open, you can switch back to TEXT FILE again later and append more results onto the file.

CAUTION! If you do close it and you switch back to text file again, choose a different file name if you don't want to overwrite the first set of results.

The current file can also be closed by returning to Output File to select a new file name.

By default, output will be written to a file called "results.txt" in the same directory as the executable.

If the Text File is chosen, a box prompting you to pick your own name, path, and directory for the file will appear.

Requesting text file creation to a:

• Write-protected floppy disk
• Non-existent drive or directory
• Improper file name

will cause program termination.

GP Format

Choose whether geodetic positions will be input and displayed in:

• Degrees to 5 decimal places
• Whole degrees, minutes to 3 decimal places
• Whole degrees and minutes, seconds to 1 decimal place

If you have chosen GP as your Input Type, GP format will determine how you must enter the "from point."

It also determines how the GP version of the "to point" will be displayed.

The number of decimal places indicated above give an input precision no worse than 3 meters.

Direction

Choose the direction of the transformation:

• To WGS 84 from the local datum.
• From WGS 84 to the local datum.

Input Type

Choose whether you will input the coordinates of the original point (the "from point") in:

• Geodetic Position (GP)
• Universal Transverse Mercator (UTM)
• Military Grid Reference System (MGRS)

Local Datum

A list of local datums will appear.

Select the desired datum by name and country/area.

All parameters needed to do a transformation with this local datum will automatically be chosen. If the desired datum is not in the list, choose the "User-Specified" item in the Datums list, prompts for the following will appear:

• Datum name
• Country/area name
• Dx, dy, dz translations to nearest meter (Sign convention is WGS 84 minus local)

Then pick the ellipsoid from the list

If the desired ellipsoid is not in the Ellipsoids list, choose the "User-Specified" , prompts for the following will appear:

• Ellipsoid name
• Semi-major axis (meters)
• Reciprocal flattening

Entering values for a User-Specified datum or ellipsoid does not permanently update either of the lists.

However, during the current run of the program, the name(s) you entered will be displayed in place of "User-Defined in the list(s), and the parameters you entered will be used in the transformations.

You can change to a different user-defined datum and ellipsoid by entering new values in place of the old ones (you can not have more than one user-defined datum or ellipsoid in the lists at any one time).

Geodetic Position

The entry screen will be tailored to the GP Format chosen:

1. Degrees: Input fractional degrees with at most 5 digits to the right of the decimal point.
2. Degrees and Minutes: Input whole degrees and fractional minutes, with at most 3 digits to the right of the decimal point.
3. Degrees, Minutes, and Seconds: Input whole degrees and minutes and fractional seconds, with at most 1 digit to the right of the decimal point.

In all formats, select the hemisphere.

UTM Grid

Input the northing and easting up to the nearest meter, and the grid zone between 1 and 60.

Choose the north or south hemisphere.

MGRS Grid

Under Grid Zone Designation, enter the zone, between 1 and 60, into the first field.

Enter a single letter designating the latitude band into the second field (see the NIMA TM's for valid letters).

Under 100,000-meter Square, enter two letters.

Again, see the NIMA TM's for valid values.

Enter numeric values for the northing and easting.

Coordinate letters may be input in upper or lower case. Input must be at least the 100,000 meter square.

Numeric parts may be from 10,000 to one-meter square.

Error Trapping

The program responds to invalid values entered into the Point Entry fields in several ways.

A character of the wrong type, e.g., a letter in a field that requires numbers, will be ignored.

So will extra characters, like a third digit to the left of the decimal point in a latitude field.

Where possible, input is checked for range validity--a BEEP will sound if a distance or angle is not in the proper range, and input will be requested again.

Some invalid entries are not caught until coordinate conversion or transformation is attempted.

In this case, one of the following error messages is displayed on the results screen, along with any partial results generated:

1. "MOLOD INVALID":

   a. Value entered was beyond 89 degrees N or S.

   b. See LIMITATIONS.

2. "N POLAR REGION," "S POLAR REGION":

   a. Point was entered in GP coordinates and was beyond 84 degrees N or 80 degrees S.

   b. See LIMITATIONS.

3. "MGRS NOT VALID":

   a. Point was entered in MGRS coordinates and ellipsoid does not support MGRS.

4. "ELLIPSOID N/A":

   a. Point was entered in MGRS coordinates and ellipsoid does not support MGRS.

5. "INVALID MGRS":

   Values entered into MGRS fields were invalid or incompatible.

6. "OUTSIDE RANGE":

   a. Point was entered in MGRS coordinates but was invalid in a way that caused its GP equivalent to lie outside the allowable MGRS area; e.g., the first letter (latitude band) was incompatible with the third letter (100,000-meter square).

7. "UTM NOT IN MGRS":

   a. Point was entered in UTM coordinates and can not be converted to MGRS; e.g., northing was so large that it actually falls in UPS region.

For a full explanation of these errors, see the NIMA TM's listed under References.

Results Screen

Both the "from" and "to" points are displayed in all three coordinate types if possible.

If an error has occurred, a message will be displayed where the MGRS value is usually given.

See Error Trapping. The "Error" field gives the uncertainty of the transformation calculation.

Note that it does NOT indicate a program error.

The "Translations" fields are local datum parameters which give the shifts between ellipsoid centers from the input to the output datum.

Any key returns to the Point Entry screen for input of a point for the next transformation.

All Setup selections, including the local datum, will remain the same.

"Esc" allows selection of a new datum. See also KNOWN BUGS.

KNOWN BUGS

Trying to write the output file to a write-protected disk freezes up your system (sooner or later).

LIMITATIONS

1. The Universal Polar Stereographic (UPS) grid is not implemented for areas north of 84 degrees north nor south of 80 degrees south.
2. You may enter points in these regions in GP format only (but see the further limits on latitude values below).
3. Transformation results will be reported in GP only.
4. Molodensky transformation is disabled above 89 degrees north latitude, and below 89 degrees south, as it is not valid near the poles.
5. The UTM overlap zone concept is not implemented.
6. Many datums/ellipsoids do not support UTM & MGRS.
7. The program traps many possible errors, but the user is responsible for its proper use. See Error Trapping.

REFERENCES

Datum transformation method is standard Molodensky formulas, NIMA Technical Report 8350.2.

Conversion between GP, UTM and MGRS is in NIMA Technical Manual 8358.2.

PROGRAMMING NOTE

The source code furnished is in Powerbasic.The grid conversion modules were designed and coded by Bradford Drew, and the user interface is based on the MADTRAN program written by Robert Zeigler (retired), both of the National Imagery and Mapping Agency Systems Center.

MADTRAN SOFTWARE DOWNLOAD INSTRUCTIONS

Summary

MADTRAN NIMA edition 1 (version 4.2) is a software program for datum transformation and coordinate conversions. You can download madtran.zip or it can ordered via e-mail or phone on a 3.5 inch diskette for IBM-compatible PC's (request MADTRAN stock number: MADTRANIBMPC).

A directory of internally documented source code (Powerbasic) is included for system developer use. The program allows input from geodetic, UTM, or the Military Grid Reference System coordinates. Over 100 datums are available for transformation to or from WGS 84. Output is automatically presented as geodetic, UTM, and Military Grid Reference System coordinates. Geodetic coordinates can be computed in degrees, minutes, and/or seconds.

Releasability

Available to the public.