Create Custom GPS Routes

Navigate the marsh with custom GPS routes

I created this article in an attempt to share my GPS knowledge that helps me safely navigate the marsh. Doing this has made me successful as an inshore angler because I was able to safely venture into and out of unknown territory.

Why use Custom GPS Routes?

Most commercial products out there may be good for “generic” freshwater lakes but are not nearly versatile enough to be reliable in the realm of inshore navigation. There are some excellent satellite imagery products on the market, but they only work for certain name-brand electronics. What this article has to teach you is good for virtually any GPS system.

The Louisiana marsh is endless and all looks very similar. It is crucial to have a dependable  ability to navigate this expanse where everything looks the same. You don’t want to get stranded!

Raining in the Marsh

You don’t want to be lost in the marsh when bad weather strikes.

Some notes before we get started

In this article I show you how to create those custom routes and waypoints using Google Earth, create a GPS file containing those items and then load the GPS file onto your GPS unit.

For the purpose of this article, the GPS I will be using is a Lowrance 332C, but the method and tools used are good for any GPS. The biggest problem we will run into is conversion issues, which will be handled on a case-by-case basis outside the scope of this article. By “conversion issues” I mean converting from Google Earth’s Keyhole Markup Language (*.kml) to whatever format your GPS uses. In the context of this article, that is the Lowrance *.usr.

I use two programs to do all of this successfully. I use Google Earth and GPS Babel, which are both free of charge and can be downloaded off the internet. If you find yourself needing help after reading this entire article, you can post in our GPS, Safe Routes and Navigation forum at Louisiana Fishing Reports. Chances are another angler can help you.

Their respective locations are:
http://www.google.com/earth/index.html
http://www.gpsbabel.org/

What is Google Earth?

Let’s talk about Google Earth. It is essentially a digital map of the entire world, represented in a small-scale, three dimensional model on your computer. Here is a picture to show you what I am talking about. At any time you can click/tap a picture to enlarge it.

Google Earth Overview

Click to Enlarge

Google Earth uses latitude and longitude coordinates (lat/longs), but it also recognizes Military Grid Reference System and other formats. I will use lat/longs in the format of DD° MM’ SS.SS”. There are many tools you can use in Google Earth. You can measure distances, view the terrain three dimensionally, measure azimuths and create routes. Google Earth has features like Street View that will let you see what an area looks like from a particular location on a street in a 360° panoramic. This is especially useful for bank fishing or learning where marina parking is without ever having been there! I strongly suggest playing with Google Earth in order to learn its full functionality, especially the route tool, as that is what this article is concerned with.

When you open Google Earth, you will see a tool that looks like a ruler in the top bar of the window pane.

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Click to Enlarge

Click on it. You will see a box pop up with two tabs. One will say “Line” and another will say “Path”.

Click to Enlarge

Click to Enlarge

That Line tab is used to measure distances. The Path tab is used to create routes. If you look at the window pane on the left, you will see a bar titled “Places”.

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Click to Enlarge

If it is not expanded, go ahead and expand it. When you create a route or waypoint, it will be created not only on the map, but also in this pane.

If I wanted to create a route from Breton Sound Marina to the intersection of Bayous LaLoutre and St. Malo, I would press the ruler button and select the Path tab. For instructional purposes, the starting point is located at 29°49’7.10″N 89°36’42.36″W and ends at 29°50’19.21″N 89°32’51.06″W. Zooming in on BSM, I would start my route there and trace it across the MRGO, down Bayou LaLoutre to my destination.

Click to Enlarge

Click to Enlarge

You can do three things to move the screen across the map as you plot your route. You can use your A, W, S and D keys to scroll up, down, left and right. You can use the scroll symbol on the right hand side of the map or you can check the “Mouse Navigation” box and hold down the left mouse button to scroll around.

Once I have completed my route, I can hit the “Save” button which will cause another box to pop up. From this box, I can view and edit all properties of this route, to include the route’s distance under the “Measurements” tab. For now, I will name the route “Stallion One”. If you look at the Places window pane, you will see your route, Stallion One. From here, you can right-click on it and hit “Save Place As”.

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Click to Enlarge

I named it “Stallion One” and, most importantly, I saved it as a Keyhole Markup Language file or .kml file and not a .kmz file.

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Click to Enlarge

This is important for conversion purposes because .kmz files usually cannot be converted to popular formats for other GPS name brands. As one last detail, I saved Stallion One.kml to the desktop, so it’s easy to find.

Opening GPS Babel you will see two sections, an Input and Output section.

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Click to Enlarge

For the input section, I click on “File Name” and browse to the desktop, where I find the route “Stallion One” saved. I select it. Then for output I go to the “Format” drop down menu and select the type for my boat’s Lowrance 332C, which is the .usr file format.

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Click to Enlarge

For the most part, file formats are listed in order of their manufacturer, making locating them in the drop down menu that much easier. Next, I click on “File Name” and save the file where ever I want to save it on my computer. I like to store them in a folder named “GPS Stuff”, so I will always have a backup after I upload the file to my GPS. Once I have completed these steps, I hit the “Apply” button at the bottom of the application. This changes the format of the route from a Google Earth .kml file to a Lowrance .usr file.

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Click to Enlarge

Now all I have to do is put the file onto an SD card, insert the SD card into my GPS and then follow the steps on my GPS’s manual to load the file for use. It seems like a lot of work, but it’s really not. With enough practice, you can throw a route together in no time at all.
If your GPS does not use an SD card, then you will need the appropriate accompanying software and USB cable. Most GPS’s come with their own software and USB cable. However, if it does not, you can try using a cable with a USB fitting on one end and a mini-USB fitting on the other end. EasyGPS is a great piece of free software that you can use to upload and download from your GPS to your computer. It will be on you to learn how this software works.

In Conclusion

Being able to safely navigate the marsh is only one skill successful anglers utilize. There are many more that include, but are not limited to:

  • finding routes that are safe to use in your boat
  • locating fish that are biting
  • selecting the right tackle that actually catches fish
  • and more!

These are all things I cover in my course, Inshore Fishing 101. If you want to learn more, then just hit the button below!

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