Overlays for DF Teams

by Marty Griffin (WA0GEH@ARRL.NET)

The EOSS Tracking and Recovery Team uses a grid overlay method to help quickly locate certain points on a map. This is helpful while driving down the road or doing quick calculations.

Grid - available from links below

The official map used is a flat (rolled) map made by MapsCo Inc. in Denver Colorado. The title of the map is "COLORADO Centennial State". What is important is that the scale is 1:600,000.

Before each flight, the grid is positioned onto the map by the tracking coordinator as a function of the launch site and the predicted landing point. Multiple reference points are then provided to the tracking team during a net so they can position the grid overlay on the map exactly the same way as the coordinator positioned his grid.

The overlay is divided into five mile grid squares with the origin in the lower left-hand corner. Locations are reported by the X and Y axis. For example, a report of 34,25 means the point is 34 miles east (right) of the origin on the x-axis and 25 miles north (up) on the y-axis.

The grid stretches to the east 90 miles. It is imperative that these grids be printed with precision or a tracking member could be misdirected by many miles.

There are several files for the grid overlay. These files should be printed with the highest resolution possible (600 dpi or higher). Also, to assure proper scaling, never print to "Fit Page". Look around on your application to be sure this option is not checked. When you print the file, check to see if the map scale fits properly by overlaying the grid onto the map scale. If it does not, then you may need to investigate the "Fit to Page" option to make sure it is turned off.

The first file is a Corel Draw file, EOSS20.CDR. It is a very large file but will offer the best resolution. It can be printed from the Corel Draw application if you have access to it.

The second file is an Adobe file, EOSS20.PDF. This file is a small file and can be printed from the Adobe Reader found on most PCs.

A third file is now available. It's a copy of the Corel Draw file in Adobe Illustrator V10 format.

Webmaster Note: 

The version number on this overlay is: V 2.0 dated 08/January/2001

These files are available in two formats. The first is "normal" view. The second is reversed. That means all the text and layout of the grid is a mirror image. If you want to print on the "reverse" side of a transparency so you can turn it over, read it easily and use mark-up pens download this reversed file.

Corel Draw File:

Adobe Acrobat PDF files:

Adobe Illustrator V10 File

Instructions for Printing a properly scaled PDF file

This is important and had me stymied for a while.

Regardless of file (normal or reversed), Open the file in Acrobat.

You'll probably have to go to page setup to change the orientation for the printed document from Portrait to Landscape. You would have figured that out on your own.

Now the tricky part.

When you select the Print option in Acrobat, the program defaults to setting the output to "Fit to Page" unlike most programs.

You MUST uncheck this option. Otherwise, the printed overlay will be reduced in size somewhat.

Uncheck it and the printout should match exactly with the originals produced years ago by the author, K�ANI Larry Cerney. At least it did in my case (Adobe Acrobat 4.05, HP Inkjet 970 printer.

Instructions for Printing a Reversed Image

Easiest way is to download the Reverse Image file above, however, if your printer driver can handle it, you may be able to print out a mirror image of the Normal view file.

I mentioned to someone that I thought Acrobat could accomplish this task. It can't. However, the driver that runs my printer does include the capability there. So, open Page Setup in acrobat and look at your printer driver's capabilities. If you see mirror image, check that and it should accomplish the task.

Why print a reversed image? Most folks print these overlays on overhead transparencies. If you reverse the image, you can have the printed overlay on the "underside" of the overlay and can make notations on the top side during a recovery operation. Then you can erase the annotations without touching the underlying overlay.