Plot Coordinates on a Map With Garmin inReach Explorer
We will take a quick look at how we can take coordinates from our current location or saved waypoints on our Delorme inReach SE or Explorer.
Let’s say that we need to plot a set of coordinates from our inReach onto a paper map. Here in our example, we happen to have a topo map produced by Delorme of Baxter State Park in Maine.
First thing is to look at the legend and with a piece of paper & pencil, mark out the scale tick marks. We’ll need this later.
Next, look at the map to see what the format the coordinates are. Here in this map we have Lat/Lon in degrees, minutes & seconds along with decimal format. We don’t see a datum specified, we will assume that it’s the defacto setting that pretty much every GPS is set to when you take it out of the box: WGS 84. This is important since our inReach only has WGS 84 as a datum setting.
Bare in mind that other topo maps, like from Canada are usually in UTM format and using NAD 83 Datum. You’ll need to use the Earthmate app and select the additional settings to read from your smartphone instead of the device. But we will focus on the inReach device.
Next, we want to match the position format displayed on the inReach to what’s on the map. We will choose degrees, minutes & seconds. From here, copy on your piece of paper the coordinates from either the Location, waypoints or messages screens.
Now back to the map, note that there are 12 tick marks between minutes. When dealing with this format, remember that there are 60 seconds in a minute and 60 minutes in a degree. So, each tick is 10 minutes.
So starting with the East/West bearing (Longitude), lets find 69 degrees. Then 60 degrees and 1 minute. Then 47 seconds, so almost another 5 ticks on the map. Mark the position with your pencil and lets find the North/South bearing (Latitude) using the same method.
Once both marks have been made on your map, take a straight edge or ruler and intersect the lines (X marks the spot).
Depending on the scale of the map, we’ll end up with a general location. But in our example, we are pretty much where we are supposed to be within a few hundred feet.