garmin mapsource decimal degreesComputers and tech 

How to switch Garmin Mapsource to decimal degrees

garmin mapsource decimal degreesCall me old school, but I still love my Garmin eTrex Vista GPS. Even this far into the 21st century, when even the most basic cell phones have a built-in GPS unit, I refuse to give up on my Garmin.

Don’t get me wrong I still use my cell phone’s GPS for the normal everyday stuff like driving, tagging photographs, the usual deals. But first hiking trips or visits to job sites you’ll probably see me carrying around my etrex.

Why do I still love this thing so much? Well it’s got several interesting advantages over a cell phone GPS: the biggest one is that is uses regular old AA batteries. If you’ve ever been away from civilization and run out of charge on your cell phone, you know how much of a pain that can be. You’ll probably end up without your phone for a couple hours, until you can find an outlet to charge from. And don’t even start on the “solar cell phone charger” story or the “battery banks”… we all know those are just bulky toys you buy for your cell phone, hoping someday they might be useful but in the end you don’t get half as much use from them as you thought you might. And if you’re out on the trail, in the middle of the rain, the last thing you want to be carrying around is a lithium battery.

With my Garmin GPS, I simply carry around or pack of AA batteries and whenever I run out (if I happen to run out, because this thing lasts forever on a pair of AA batteries) I simply pop out the old ones, and 30 seconds later I’m back in business.

Plus the recording features on my Garmin GPS are really convenient. I don’t have to go into a bunch of messy software settings in order to get a track recorded, or a waypoint stored. I just turn on the GPS and go. It knows what to do.

And, another plus: the GPS data isn’t so manipulated and distorted. When you use your cell phone’s GPS, the cell phone applies a whole bunch of corrections and adjustments to make your GPS behave like you’d expect it to. It uses position data from nearby cell towers, position data from wifi networks, position data from GPS, mixes them all up, and comes up with your position. That’s fine if you’re playing Pokemon GO, but if you’re looking to record GPS data or tracks, in the cleanest way possible, all those adjustments can really mess you up. With the Garmin units some corrections are applied, but your data isn’t as heavily manipulated and adjusted as when you get it off your phone.

To download the data off of the GPS you have to use something called Garmin Mapsource, which is basically Garmin’s software for interfacing with your GPS unit. You can take waypoints and tracks off the GPS memory, put them on your computer, and do some basic conversions on them. It has a built-in map, but it’s way below par when you compare it to something standard, like Google Maps. But, it works.

garmin mapsource decimal degrees

There is one annoying thing about Garmin mapsource which is that by default it uses degrees minutes and seconds to display your coordinates. In other words if you want to see latitude and longitude you get something that looks like “N9 52.344 W83 14.942”. While it’s true that degrees minutes and seconds have been the standard for many decades for displaying latitude and longitude, they don’t work well if you need to transfer coordinates from one application to the other. For example if you want to export your coordinates from Garmin Mapsource to an Excel spreadsheet. The DMS format messes up Excel’s formatting and calculations.

Fortunately I did some searching and found how you can switch Garmin mapsource from degrees minutes and seconds, to decimal degrees. Decimal degrees is the standard that Google Maps uses, and it also transfers really well to Excel and other applications. If you still use Garmin Mapsource like me, I suggest you make the switch.

The option to switch to decimal degrees is buried in the preferences menu for Mapsource, and it really doesn’t have a clear title that tells you this is the option you need to change. So let me clue you in on how to switch Garmin Mapsource to decimal degrees:

  1. Go into the preferences menu. The prefernces menu is located inside the edit menu. You can also press Ctrl-Shift-P to access it.
  2. Look for the tab that says “position”. In this tab you’re going to see an option that says “grid”.  And it’s probably going to say “Lat/Lon hddd’ mm.mmm”.
  3. Switch the grid to “Lat/Lon hddd.ddddd”
  4. Keep the datum option where it is (usually WGS-84. Unless you have a really good reason to change it, for example if you’re using a local coordinate system. For most people, WGS-84 is the standard to use. If you’re not sure, leave it on WGS-84.

Press OK to exit the menu, and Mapsource will now display decimal degrees.

garmin mapsource decimal degrees

Bet you’ve been looking in the units tab, where there’s no option for degree measurement. Yeah, happened to me too. I have no idea why Garmin decided to place the degree units in its own tab. They should have just moved the Datum setting to the Units tab.

Unfortunately the solution is still not perfect, you’re still going to get the “N” and “W” letters in your coordinates, but, at least you won’t have to be dividing everything by 60 to get your decimal degrees.

So there you go. That’s how you switch Garmin Mapsource over to decimal degrees. If you’re like me and still have one of these GPS units, enjoy… and take good care of that GPS… it’s well worth it.


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