Dear Capt. Paul:

First, let me say, as a longtime subscriber to Louisiana Sportsman magazine that your articles are the most interesting and informative on GPS topics I have ever read. I can't wait to get my magazine every month to get the latest and greatest.

I got started with GPS years ago with one of the first Magellan handhelds, and am fairly familiar with navigation basics such as setting waypoints, GOTO, etc.

I now have upgraded to a Magellan Meridian Marine GPS with the 64mb SD memory card.

What is the best and most-economical way to access nautical charts that can be uploaded into my SD card? I looked back through your past articles to see if I could find enough info to be able to figure it out on my own but was not able to do so.

We fish and boat in so many different areas that having all the required Magellan Blue Nav CDs would just not be practical or affordable. For example, we'll fish Islamorada, Fla., next month, then it's Venice, Port Eads and Grand Isle the rest of the year.

Could it be as easy as cut and paste from Maptech online charts, NOAA sites, or other free chart sources?

Thanks very much for any help you can give a faithful reader.

Stu Law

Baton Rouge

Hello Stu,

I am very pleased that you enjoy my monthly column in Louisiana Sportsman magazine. Thanks for your comments.

Are you aware that I also answer GPS questions on the Louisiana Sportsman Website at www.louisianasportsman.com under the "Ask Captain Paul" posting category?

I mention this because I get a lot of requests for the exact same information that you are requesting. You can even do a search of the topics on the Website to enhance your GPS library of waypoints and "how to's."

I bet you found quite a difference between your older GPS unit and the new Magellan Meridian Marine unit. Isn't it a fantastic unit?

About your mapping, there is no economical or practical way of loading maps from one company into a GPS manufactured by another company. Without writing your own software and programs, you will only be able to use Magellan Mapping in your Magellan GPS unit. Maptech mapping software at this time cannot be loaded into your unit. You will have to use the respective Magellan MapSend mapping software for your Magellan GPS unit.

As an explanation, the Maptech maps are actual scanned topographical and NOAA charts and maps, where the internal maps required for the GPS unit are computer drawn lines that depict a map.

I believe that the Maptech mapping programs are some of the finest in the world, as they offer topographical maps in various scales, aerial orthphotos, NOAA charts and navigation photos that are all connected to their software program that allows you to mark waypoints, routes and tracks, print a paper version of the map as well as transfer the waypoint data to and from over 50 different brands and models of GPS units.

The only way to use the Maptech programs is to load them into a laptop computer or a Palm unit that is connected to a GPS card or GPS unit.

So for practical choices, you are left with selecting and buying the Magellan mapping software that best serves your needs.

As the types of mapping, I agree with you and your dilemma. It is going to be hard and expensive to get all of the Blue Nav Charts that you will need.

If you are not fishing much offshore waters, then the way to go is the Magellan MapSend TOPO in the U.S. This version of their mapping software is made from U.S. Geological Survey Topographical Maps redrawn for their GPS units. As you know, the best mapping in the US are these topo maps. Topo maps are designed to show land detail. In my opinion, they offer considerable more detailed mapping of the coastal fishing areas than do the Blue Nav Charts that are designed for GPS units.

The Blue Nav Charts are based on NOAA Marine Charts. These charts are the best in the world for showing the Aids to Navigation (ATONs) and features in and along commercial waterways. Some of the latest charts (2003) still show land masses that are no longer there.

Such a feature is Snake Island in Black Bay, just west of Breton Sound. The just-released NOAA chart No. 11364 shows the island, even though Snake Island has not existed for about 20 years. I believe that the effort in keeping the land features up to date is just not committed to areas where there is not a lot of commercial sea traffic. If you are fishing a lot of offshore locations, then a limited amount of Blue Nav Charts will be required, but I would keep them to a minimum.

The topographical maps are designed to show land futures, and Magellan offers their MapSend Topo U.S. that covers the entire United States.

Using your 64mb Secure Digital memory card, you should be able to load Magellan MapSend Topographical maps that would cover an area along the northern Gulf of Mexico from Houston to Miami on the south and from a line that would be on the same latitude as Alexandria to about Savannah, Ga.

I have a Magellan Meridian Platinum, and have loaded two 128mb Secure Digital Memory cards with Magellan Mapping software. The two cards allow me to instantly have available the Magellan MapSend topographical mapping for the entire southeastern U.S. from Texas and Oklahoma to Washington D.C. to the Gulf of Mexico and Key West, Fla.

I also have and use the Maptech Terrain Navigator Pro mapping software. I use this software to pinpoint my positions and routes. I then simply download the position information into my GPS unit, knowing that it is placed at the precise location that I need. This program coupled with your internal mapping of your GPS offers a product combination that is hard to beat.

If N30 25.505 x W91 03.996 or 2824 mean anything to you, open the attachments and view the differences that I described. The position is determined using WGS 84 datum and is stated as DDD,MM.mmm. One of the attachments is the Magellan MapSend Topo U.S. as it would appear in your GPS, one is the Maptech topo at 1:24000 and one is the Maptech orthophoto at 1:12000.

Wouldn't it be nice to be able to use the Maptech maps in your GPS? But, as I said, it is not yet feasible.

Get back with me and let me know if this information steers you in the right direction.