~ Captain Paul's response to: ~ The Truck Man ~
I’ll get to the heart of your question, but first I must offer a suggestion.
I know that you requested info on how to transfer a “Path” or “Track” and certainly you can do that, but it would be far better to install the data in your new GPS unit as a ROUTE.
A “Path, Track or Trail Back” feature is designed to be only a TEMPORARY route that records the track in a fashion that usually replaces the first part of the track back when all of the track back memory is used. It is called a wrap method, much like a fan belt traveling around a pulley. After using all of the memory, it starts over again from the point where the memory ran out.
In order to make a permanent record of your route, you must actually make and save a ROUTE. Routes are made up from a series of waypoints which the GPS unit connects, by a straight-line course. It assumes that you can navigate from one waypoint to another to another, to another, etc., etc. In addition, some units with the proper mapping software will design the route for you using existing waterways much as an automobile GPS unit would do. I prefer to designate my own routes as the software does not know my boat’s requirements.
Start from your launch. Mark and save it as a waypoint, then go to the first turn that you make in your course, mark and save it as your second waypoint, then to the next course change and mark and save it, then to the next, and the next, and the next, until you reach your destination. Then go to the route function and compile these waypoints into a route. Name and save the route. You will then have a permanent (if there really is such a thing) record of your voyage that you can summon and navigate over and over again.
In navigating the route with our GPS unit, you can select the MAP, HIGHWAY or COMPASS page to guide you through the route. As you reach one waypoint the course and direction to the next one will be provided. The unit will give you the distance and courses from one waypoint to the next and even an expected time of travel or arrival. To return back to the launch from your final waypoint, simply INVERT the route and navigate the courses back to the beginning.
Using the path of track feature to steer a vessel will cause you to have an ever increasing path line on the screen which will become thicker and thicker with each use. In addition it causes you to have to constantly look at the GPS screen. The unit will only store a very small amount of different tracks, where as that unit can accommodate 100 different routes.
With that out of the way, here is the information on the ”how to” accomplishment the data transfer.
The Garmin web site for the unit states, “If you have waypoints, tracks or frequently used routes stored on another manufacturer’s GPS product – or on a Garmin handheld device – now it’s easier than ever to transfer those items to your new Garmin chartplotter, via industry-standard GPX software formatting. GPX is an open standard format for GPS data exchange across platforms and applications. With this easy-to-use interface technology, Garmin has taken “no waypoint left behind” to a whole new level of trade-up convenience.”
The newer .gpx formatted data files are an effort to have one type of data file for the industry. However, some newer Garmin units require a data file to be written to a specific protocol Garmin calls an “.adm“ file.
I don’t believe that the GPS Babel program has a conversion to an .adm file format, but you can try the Babel conversion to a .gpx file format. But, don’t despair, there is a way.
But, before actually trying to write a file from a Garmin Data Transfer program to a spare and let me repeat, a SPARE, data card you must first place the memory card in the GPS unit and turn the unit on. I suggest that you do any function with the unit, simply changing a screen page will do. This procedure causes the GPS unit to install a code on the card that is recognized by the Garmin program in your computer and later again by the GPS unit. Without doing so, the GPS unit will not accept the data information. This is a must in trying to do data transfers. Trying to use an existing map data card for the transfer could over write existing map images thusly ruining the card.
First, save the Google Earth data to a file, I suggest saving it in the Google .XML format. I save my data to a folder I named GPS then in a sub folder for each of the different areas I fish and hunt.
Then, using one of Garmin’s data transfer programs, transfer the data first into the data program then onto a spare data card.
Garmin offers a free data transfer download program on their web site called HOME PORT. I strongly recommend that you install the program in your computer. It will save you time and effort in doing this and future transfers to and from the GPS unit and your computer. It will allow you to back up all of the waypoints, routes and tacks in your GPS unit to a file in your computer or on a thumb drive. They also provide a program for land use called BASE CAMP. Actually either will work but the Home Port program is designed for marine type units. Both are available from the Garmin web site at https://buy.garmin.com/en-US/US/prod64242.html
It is available for both Windows and Mac systems. As said, it is a free download. If you own a Garmin unit, you should have one of these two data transfer programs. This program allows you to install a Google file into the program then onto a data card as an .adm file.
Once installed in the Garmin program, click on the FILE icon then the Import from window to the file folder where you saved the Google .XLM file.
Once doing so all of Google data will appear in the Home Port program.
Place the spare memory card in your card reader. Then select the small icon at the top left of the screen that indicates two small GPS units. One is send “to device” and the other is “receive from.” Select the transfer “to” option and window will show the GPS model and serial number that was written on the card. In that window you will have an option of transferring it directly to the unit, or to the spare data card. If you have the unit connected directly to your computer select that option. If it is not, select the option that writes it to the data card.
One word of caution, when using the settings in your GPS unit as compared to the options in the Google Earth program be sure that the Datum agrees.
Let me explain. My information is that Google Earth uses a EGM96 Geoid in displaying their Google Earth programs. I believe that the Google Earth images are corrected to use WGS 84 datum. So if that is the datum that you use in your GPS unit, simply enter the Google coordinates into your unit. Be sure to check the position format to be sure that they also agree. You can either change the Position Format (Location) in your GPS unit or you can change the Google Earth display by going to the TOOLS/Options link at the top of the program and select what ever position format you normally use. Be sure that they agree.
So, if you are using your GPS unit in a relative flat area, such as Louisiana, or any sea level environment, I would assume that the figures are fairly accurate. However, if you are using the WAAS feature in your GPS unit in order to get the 3 meter accuracy via the differential system, your position via Google may only be to a position accuracy of 20 meters. Your WAAS activated GPS unit will produce a more accurate position fix on the actual position.
I would use the Google info but use it with suspect. When you get to the actual location you should use your WAAS activated GPS unit to “refine” the actual or true position.