GPS map innaccuracies

[Snomad]

I have a 60CSx with the Garmin Mapsource Canada topo maps. I have found during hunting and fishing that your position relative to the map is not accurate, like 60-100 yards out. An example was travelling down a lake at least 50 yards offshore and it shows us merrily travelling along on shore. Is there a way to sych your actual position with the same place on the map?

 

[Sno-Xr]

Does it seem like the direction that it is off is the same at all times. example, does it show that you are always North of your actual location?

 

[northernguy10]

gps

I have had many different gps in the past. they are all off by as much as 100 yrds to 5 yrds for security reason. my 60 csx is usually 3 to 30 yrds, 9 out of 10 times its dead on, then off by 30 yrds. I notice that topo is good at showing a lake, but if you want detailed shore line you need inland lakes , that what I had to do in Ontario. its a little more acurate.

northernguy10

 

[canadianhunter]

Another thing is your GPS must be set to the correct Datum and Coordinates for your area. Your book will tell you how to do it and info. is usually near the back of the book.
This coordiates your GPS to the maps.

 

[Snomad]

The GPS always seems to be in error to the north on the map. As in; we are shown on shore at least 100 yards to the north of where we actually are on the lake. Another time we walked straight north out of dense bush to a highway and were shown at least 100 yards north of that highway when we came upon it. (It would of course be much nicer to come upon the highway before you expect to than after the map says you are there.)

This is not GPS position inaccuracy. This is a waas enabled unit and the error distance from your actual position is displayed on the screen and is in feet. If you have at least 8-10 satellites this error I have seen as low as 11 feet. Even my old GPS 12 was not bad.

The error just seems to be that the map and the actual GPS position are not aligned. And again, it seems to be a similar amount in the same direction.
Canadianhunter, thanks for that heads-up, I didn't know about the Datum and coordinates for the area needing to be set. You would think that if you buy the maps from Garmin you would be good to go.

With my old GPS 12 I was able to upload my tracks to Softmap software which is comprised of actual scans of paper topo maps. These are very accurate maps but I noticed that my tracks were often off by small amounts compared to trails actually shown on the maps. That I attributed to the inherent inaccuracy of that non-WAAS enabled GPS.

Thanks for the responses.

 

[yamahas]

with the compass issue some GPS's dont have a magnetic compass built in so it looks at the direction you are moving at and take it as a reading. Therefore if you stay in one spot and turn the gps can not tell what direction you are facing... i think...

 

[scraggly]

I have a garmin 60 cx with the topo canada maps and have found it to be fairly accurate. I even download the tracks on my computer to google earth and they follow the woods roads right on the money.