Coordinates on GPS different from Google Maps?

I try to put specific coordinates on a GPS, and the point that appears on the map of the GPS is different from the one on Google maps.

Basically the point shown on the GPS is not totally different place than on google maps

How is that possible?

Thank you in advance.
There is more than one way to express latitude and longitude numbers such as decimal degrees or degrees decimal minutes. Make sure you are using the same method for both systems. If you need to convert from one to the other, there are internet sites that can assist you such as

GPS Latitude and Longitude Converter

Ken in Regina
Hello Von,

There are many things that can be causing this.

1. Your GPS is a consumer device. It is only accurate to within a few meters at the very best. And that depends on having a very good signal. Your GPS may have a screen that tells you what it thinks the accuracy of the current reading is. That is useful information but it is also only an estimate and does not -- can not -- tell you which direction it is inaccurate.

.. 1a. You can improve this by standing in one place for at least a couple of minutes to let the reading stabilize before recording the coordinates. If your device has an "averaging" feature, use it for a minimum of thirty seconds, preferably more, whenever recording a location.

For more information on GPS "accuracy" you can read this thread:


2. It is necessary to make sure your GPS device and Google Maps/Earth are using the same "datum" (look for "geodetic datum" with your search engine). The simplest is to make sure your GPS device is set to WGS84 (there is usually a place in the Settings on your device to do this). I'm pretty sure WGS84 is the datum used by Google Maps. Using different datums on the two displays will result in huge differences in where the same set of coordinates is displayed on the maps.

3. The calibration of Google Maps/Google Earth is not always correct. You can see this on the maps if you have set the view to the combined road map and aerial view. In many places you will see the roads from the road map do not lay exactly on top of the roads in the aerial view. I have seen examples where the calibration is out by as much as 1/2 mile. Yes, that means the road from the road map was laying over the aerial map view 1/2 mile from where the same road was displayed in the aerial view.

4. You did not say which Google Maps view you are comparing with the maps on your GPS device.When you combine the inaccuracy of your consumer GPS device (point #1) and the inaccuracy of Google Maps calibration (point #3) you will find that the opportunity for accumulated error can be very large.

5. Similar to point #3, the calibration of the maps in your GPS device probably is not perfect, either. If the calibration error of the maps in your device is in the opposite direction of the calibration error in Google Maps you can see the opportunity for another large error in what you see displayed on your device maps versus Google Maps even if the calibration error in each is small.

There are other considerations but those are the major ones to be aware of.

Thank you very much Terry and Ken, This is really helpful.

I have to let the GPS settle in for a while as you explained and I was already adding waypoints of spots in another country I want to go.

I have just tried the converter and I noticed that when I put the calculated result of coordinates I put on Google Earth/Maps, the spot shown in the GPS seems to be right one.

It looks like I have to convert each coordinates I put on Google to get the right spot on the GPS.

I had no idea I need to make a conversion from Google Earth to GPS, is that right?

Thnak you again.
The coordinate system used by a GPS - assuming you mean a handheld or PND - can be changed. Decide on a system that both the GPS and GE can agree on and you won't have to convert it.

Ken in Regina
Von, you haven't said what device you have. You should be able to set its coordinate entry/display configuration to the one that matches Google Maps/Earth.

On a Garmin device, like the Nuvi models, you might try something like:

- poke the Tool icon (little wrench)
- poke "Settings"
- poke "System"
- poke "Location Format"

- select the format that matches what you are having to enter in Google Maps/Earth.

Thank you.

I have a Magellan Explorist 510.

Basically, if I put a coordinate like 4522'06 N on GE, it is going to give me 45.3683333333. And yet I took the coordinates from a book that says the coordinate is definitely 4522'06 N
' I let the second coord besides for the example)

So basically to have something similar to what GE shows, on the GPS I have to put 45.3683333333, because putting 4522'06 N gives me something different on the GPS.
But one of those is in degree-minutes-seconds format and the other is decimal degrees. Try changing the Explorist coordinate system.

http://support.magellangps.com/support/assets/manuals/112-0012-001_A.pdf Check page 41 for Settings - Navigation.

Thank you both of you Terry and Ken > problem solved.
How accurate is GPS for Location if using same GPS and pass by same location at same time? Will I get the same GPS location information each time or will it vary? If I use a different GPS - will I get different location reading for the same location?
The accuracy of GPS devices is quite good; certainly within 50 feet or so even for older units. However, you must decide whether the accuracy of the maps you are using is as good as necessary. This can depend on the age of the software.

Ken in Regina
The simple answer is that you will get a slightly different coordinate pair each time you pass the same location.

For the same GPS on multiple passes it will be affected by things like:

- your speed,
- whether there are buildings, trees, or other things that can affect line of site to the satellites at different times of day and on different days,
- weather condition differences that may affect satellite reception between different passes.

Different GPSs on different passes will have all of the above causing differences plus different GPSs can have different sensitivity to those factors.

Finally, you may not take precisely the same path on each pass.

This will produce different readings on every pass if you look at the coordinates. They should be minor if the GPSs are of good quality and mounted in a good location for satellite reception and the location displayed on a map may look identical for each pass, as long as the maps used are identical.

When we were in Greenwich, London, England I stood on the Prime Meridian and checked the location with one of my GPSs. It didn't read 0.00000.

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