Accuracy of a trace

[Gadwin]

I did not specify, the satellite photos are from Mobac which accurately records the orthos from Google Earth and IGN, there is no offset, if I place the coordinates directly on Google Earth, there is no no lag either.

I think you may be missing the point.

It does not matter that your choice of satellite imagery matches perfectly with Google Earth satellite imagery because, as mentioned previously, Google Earth satellite imagery does not always agree with Google Earth satellite imagery. Google Earth satellite imagery can shift several meters from one release to the next. So when your data matches Google Earth satellite imagery precisely, it only does so for that release, and will not match other versions of Google Earth satellite imagery that are shifted one way or another.

Please examine these Google Earth Satellite Imagery examples from JAN 2022 and AUG 2022 for the NIZAS II reference point coordinates:

NIZAS II Google Earth Shift

NIZAS II Google Earth 2022-01 2022-08 ANI.gif

I think it is not legit to just screenshot the different timelayers in google earth pro and overlay them. The GPX file contains the precise date and time and google earth pro takes it into account. When I tried to slide the timeline in google earth pro, my gpx track vanished because it was not taken at this time.

[GPSrChive]

I did not specify, the satellite photos are from Mobac which accurately records the orthos from Google Earth and IGN, there is no offset, if I place the coordinates directly on Google Earth, there is no no lag either.

I think you may be missing the point.

It does not matter that your choice of satellite imagery matches perfectly with Google Earth satellite imagery because, as mentioned previously, Google Earth satellite imagery does not always agree with Google Earth satellite imagery. Google Earth satellite imagery can shift several meters from one release to the next. So when your data matches Google Earth satellite imagery precisely, it only does so for that release, and will not match other versions of Google Earth satellite imagery that are shifted one way or another.

Please examine these Google Earth Satellite Imagery examples from JAN 2022 and AUG 2022 for the NIZAS II reference point coordinates:

NIZAS II Google Earth Shift

NIZAS II Google Earth 2022-01 2022-08 ANI.gif

I think it is not legit to just screenshot the different timelayers in google earth pro and overlay them. The GPX file contains the precise date and time and google earth pro takes it into account. When I tried to slide the timeline in google earth pro, my gpx track vanished because it was not taken at this time.

There were no GPX files used for the example provided.

I simply entered the coordinates for the reference point you provided into Google Earth and compared different imagery dates for that location. You can see the coordinates are the same at the bottom of the screen!

[mimichris]

Which proves that the lag that I sometimes have on the tracks does not come from the maps but from the tolerance of the 66sr which is given for +/-3m, which corresponds to my lags, in reality it is very little but we wants it to be perfect....

[GPSrChive]

I don't agree with you, if you put the mouse arrow on a point (pebbles) of your animation, the pebble is always under the arrow from frame to frame but that's just the change definition that gives this effect, experience it.

Anyone can see the entire map and everything in it shifts from one date to another with the same coordinates selected for the center point.

You must be delusional. I do not care that you are, but we are not going to spread misinformation here.


A quick recap for those having trouble following along:

I notice this inaccuracy by staying in the middle of the road or the path, sometimes an offset of 3 to 4m measured on the Google Earth map which I think is precise, likewise on the IGN satellite map of France.

... on the Google Earth map which I think is precise ...

Do not be fooled, it is not precise nor is it accurate!

The IGN France maps are very precise, they are used to create IGN maps at 1/25,000, this is the reference and I have exactly the same offset as on Google Earth.
There is a geodesic system in France precise to the cm, we can access the terminals and markers, their positions and their precision.

I consider the Google satellite map to be accurate like the IGN one.

Whether on the IGN and Google satellite map, the track offset is the same. So I consider the Google satellite map to be accurate like the IGN one.

Or they are both 'off' by the same amount...

You can see that the geodetic marker is at the correct coordinates on both Google and IGN satellite maps.

I did not specify, the satellite photos are from Mobac which accurately records the orthos from Google Earth and IGN, there is no offset, if I place the coordinates directly on Google Earth, there is no no lag either.

I think you may be missing the point.

It does not matter that your choice of satellite imagery matches perfectly with Google Earth satellite imagery because, as mentioned previously, Google Earth satellite imagery does not always agree with Google Earth satellite imagery. Google Earth satellite imagery can shift several meters from one release to the next. So when your data matches Google Earth satellite imagery precisely, it only does so for that release, and will not match other versions of Google Earth satellite imagery that are shifted one way or another.

Please examine these Google Earth Satellite Imagery examples from JAN 2022 and AUG 2022 for the NIZAS II reference point coordinates:

NIZAS II Google Earth Shift

NIZAS II Google Earth 2022-01 2022-08 ANI.gif