Thursday, March 18, 2010

Navigating with the eTrex H and TOPO! Custom Maps

A short time ago, I posted this review of the Garmin eTrex H GPS and the TOPO! custom mapping software from National Geographic. In that review, I stated that for the combined price tag of about $200, you can meet or exceed the capabilities of mapping GPS units that cost two or three times as much.

It has since been pointed out to me that there are professional-level GPS/GIS tools used by surveyors, land managers, foresters, etc., that are far more sophisticated than what I demonstrated. I’m not familiar with those tools, but considering the expertise of those who pointed that out to me, I have to assume that is a fact. I’m sure they come with a hefty price tag, however. So I will qualify that statement now by saying that I was referring to popular GPS models commonly available to consumers through normal retail outlets. In other words, the kinds of GPS units that hunters would normally be considering for recreational use.

With that qualification out of the way, let’s dive in to how you can use these very cost-effective tools to determine your location in the field and then navigate to another location. It takes a little bit of prior preparation when you are creating your custom topo maps and a couple minutes of time once you are on the ground, but with a little practice you can pinpoint your location on the map with a very high degree of accuracy.

If you are a newcomer to using a map and compass, or if you just want a quick review, you might also want to check out these articles on compass basics, topo map basics, and navigating with a map and compass.

One final point that I brought up in regard to a photo in the book Mapping Trophy Bucks which I reviewed here... make sure you don't lay your map on anything that contains iron or steel as that can severely affect the magnetic needle on your compass, giving you a false reading. Also, it you are navigating in the dark, keep your flashlight a safe distance away from your compass, because it can affect the compass reading as well.

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