Problems with my Oregon 400t

[+fendermallot]

Today I turned on my 400t and went to go do some caching with my boy. We got to where the first cache was and I realized that map was off by ~150-200 feet. I was standing on the corner, near where the gps said the cache was, but my gps said I was over 200 feet away from the corner.

 

Is this fixed by doing a factory reset, getting a new gpx file for the caches, anything?

 

Any help/ suggestions is appreciated.

[+tarbal]

Did you have it in automotive mode and locked on road? This one always gets me when I forget to change profiles.

[+fendermallot]

nope, no profile change. Still set to geocaching. I did a factory reset, no help.

 

Just to help visualize the problem. I my street runs E to W. I live on the East side of a side street. My GPS says I'm currently standing on the West side of the street.

[+tarbal]

Did you just turn the unit on? Sometimes it takes a while to get the most accurate bearings (3-5 minutes). If I reset or do any updates I let my unit set for at least 20 minutes to half an hour before I will use it. After that it is just a quick stat up and go. Did you happen to see the accuracy reading to make sure you had a good lock? This sounds like it is off a lot. I have never had my Oregon been off by that much. I am usually within 10-15 feet of the cache at most.

[+fendermallot]

ok, I've discovered that the topo maps that are pre-loaded are the culprit. I disabled them and then enabled a custom map that shows me in the correct position. When I reverted back to the us topo 100, I was back in the incorrect spot.

 

How can I fix this?

[+fendermallot]

Did you just turn the unit on? Sometimes it takes a while to get the most accurate bearings (3-5 minutes). If I reset or do any updates I let my unit set for at least 20 minutes to half an hour before I will use it. After that it is just a quick stat up and go. Did you happen to see the accuracy reading to make sure you had a good lock? This sounds like it is off a lot. I have never had my Oregon been off by that much. I am usually within 10-15 feet of the cache at most.

 

When I was out, I had a full 5 bars signal, and 12-15' accuracy.

[+fendermallot]

I now have both maps loaded, and am telling the gps to recognize two data fields. my pointer is sitting in the correct position now. I guess I'll go with this. Besides, the custom map actually distinguishes parks where the us topo 100 has just blank spots.

[+jopasm]

It sounds as if it might be a datum problem. USGS topo maps often use the NAD27 datum but GPS units use WGS84 by default if I remember correctly. Check the datum on your unit and check the custom maps.

[+StarBrand]

Garmin's topo maps are notoriously incorrect for roads. Topographic features are spot on but roads are often a few hundred feet off. Load one of the free maps from gpsfiledepot.com.

[+fendermallot]

Garmin's topo maps are notoriously incorrect for roads. Topographic features are spot on but roads are often a few hundred feet off. Load one of the free maps from gpsfiledepot.com.

 

I did, Now I have them overlaid and all is well.

[+Ladybug Kids]

Garmin's topo maps are notoriously incorrect for roads. Topographic features are spot on but roads are often a few hundred feet off. Load one of the free maps from gpsfiledepot.com.

Yup...here's a prime example near Willow, Alaska.

The yellow track log records a 12-mile skijor race I did last January. The track follows the edges of the lakes very nicely. However, it shows the Parks Highway (Hwy. 3) running across the middle of the lake where the race started. Might be possible during the winter months, but the highway, subdivisions and railroad are actually a good quarter mile or more to the east of where they are depicted.