Improving accuracy

[Seronac]

My new Garmin eTrex Vista HCx is great, but it's off a bit: by about 100 ft. to the east. In other words, it thinks I am about 100 feet east of my actual position, as compared to a number of other sources, like Google Earth, topo maps, etc. (North/South position is just about perfect.) Any ideas on how I can fix this? Many thanks.

 

(I wasn't sure where to place this question, so I went with GPS Units and Software. I hope that's OK.)

[gallet]

My experience is that my VistaHCx is within a few metres of what maps.google indicates. What map datum are you using?

 

I use decimal degrees. I also find it to be accurate with topo maps providing I set the correct map datum.

 

As a check the first thing I would do is set your unit to read DD.DDDD (decimal degrees) and check it against www.maps.google try an intersection near where you live.

[jmundinger]

Another test you might try is to search for a couple of benchmarks in your area.

[gallet]

In fact a few months ago I bought a Venture and had it shipped to Australia. It still had a waypoint marked "home" in it, (doesn't everyone) and I looked up the coordinates on maps.google for fun and sent the seller an email and told them where they lived and asked them how accurate it was. They replied that I was spot on.

[LinXG]

Hi seronac

 

...it thinks I am about 100 feet east of my actual position, as compared to a number of other sources, like Google Earth, topo maps, etc. (North/South position is just about perfect.)

 

If it is consistently off by 100ft then the first thing to do would be check the DATUM setting. Also be careful juggling information sources, Google Earth uses WGS84 as its datum and topo maps are typically NAD27 or NAD83. So you can't directly compare the two without doing a conversion first.