This discussion has been locked.

You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Accuracy of Garmin etrex 20 GPS in Spain

Former Member over 11 years ago

I have started using this GPS near Madrid, and have a map with which i need to plot the location of specific localities.
I assume the co-ordinate system of the map is in UTM, but when i select UTM UPS as the position format for the GPS, the readings are consistently about by about 90m to the East and 200m to the South.
I was wondering if there was anyway to account for this on the GPS or whether I might have the wrong settings selected.

Thanks

0 Former Member over 11 years ago

I have started using this GPS near Madrid, and have a map with which i need to plot the location of specific localities.
I assume the co-ordinate system of the map is in UTM, but when i select UTM UPS as the position format for the GPS, the readings are consistently about by about 90m to the East and 200m to the South.
I was wondering if there was anyway to account for this on the GPS or whether I might have the wrong settings selected.

Thanks

Here is a way to check the accuracy of your GPS and your other map of Madrid.
I assume you are making waypoints of those specific locations using the 20.
Make sure you have selected WAAS/EGNOS using System Settings. Owners manual page 30. And Battery Type.
Install Google Earth.
Install Garmin BaseCamp and then open it and connect your 20.
Click > Device > Receive from Device.
Select (highlight) your waypoints.
Click > View > Google Earth > Selected Items.

Google Earth will automatically open and show your waypoints. I do not know about Spain but in the USA Google Earth has been very accurate in its plotting. You should be able to zoom up on your waypoints and see if they are plotting properly. If they plot properly then your GPS is functioning properly and that other map you are using is not accurate.

0 Former Member over 11 years ago

Check what datum the map is using. This should be specified somewhere on the map.
UTM is usually used with the WGS84 datum, and this is what the Etrex will use by default. But the map might use something different, and this could make the coordinates a few hundred metres out.

From a quick search, it seems Spanish maps usually use the "European 1950" datum (or maybe "European 1979"), so try setting that on the Etrex.