GPSrChive Discussion Forum

Nail wrote: Fri Apr 07, 2023 10:15 am On the windowsill in front of the window.

Spoiler

GNNS.jpg

If it doesn't cause you any trouble, create points based on the data from the
Gpsmap 67 and Gpsmap 66sr screens, check in Google Earth the distance to the window in which you carried out the test.
In this way, we will obtain information whether the devices have similar accuracy.
I'm curious what was the discrepancy between the position indicated by Gpsmap 67 and Gpsmap 66sr.

I cannot seem to open and view Nail's GNNS.jpg file. I have been getting consistent GNSS accuracies of 7 feet and occasionally 6 feet with the latest firmware 4.70 GPS 2.46 as reported on the About page of my GPSMAP 67.

neilwoody wrote: Sat Apr 08, 2023 1:05 pm I cannot seem to open and view Nail's GNNS.jpg file.

Spoiler

https://www.gpsrchive.com/Discussion/vi ... 403#p10403

neilwoody wrote: Sat Apr 08, 2023 1:05 pm I cannot seem to open and view Nail's GNNS.jpg file.

Please select the link to the original post to view the uploaded image.

Original Post Link

Original Post Link.png

Przekątny wrote: Fri Apr 07, 2023 9:59 pm
If it doesn't cause you any trouble, create points based on the data from the
Gpsmap 67 and Gpsmap 66sr screens, check in Google Earth the distance to the window in which you carried out the test.
In this way, we will obtain information whether the devices have similar accuracy.
I'm curious what was the discrepancy between the position indicated by Gpsmap 67 and Gpsmap 66sr.

Home tests mean nothing to me. No engineer will take these tests into account. All I know is that the GPSMAP 67, compared to the 66sr, takes much longer to activate the satellites when I'm at home. However, outside after starting it is in the position faster than 66sr, because it starts up faster ).
Below is an outdoor test, blue sky, GNSS readings at 67=8ft, at 66sr=6ft. They were in place for about 5 minutes. 67 was located about 100cm from the actual position and 66sr 150cm.

Spoiler

67vs66sr18.jpg

GPSrChive wrote: Fri Apr 07, 2023 12:26 am Looks like whatever software you used to convert the GPX or FIT file (you did not specify which) to KML format made some mistakes....

I downloaded the kml file via Garmin Connect on the website and opened it on my computer with Google Earth Pro. The interpolated line is the same as on Garmin Connect and on the device itself. So it is no mistake by the software. This happens not often, but it does happen also today on another hike. This contributes also, that afterwards it seems to be poorer the accuracy although the marks were ok.

Garmin Connect exports data in various formats,
try to download in .gpx or .tcx file, Google Earth reads it
indicated formats.
The circles in the attached photo are track points.

Nail wrote: Sat Apr 08, 2023 3:25 pm Home tests mean nothing to me. No engineer will take these tests into account.

Thank you for posting the information what the actual position was indicated by the points. The fact that no far-reaching conclusions can be drawn from parapet tests. When hiking, it is important to indicate the position, not the value of the GNSS indicator.

Gadwin wrote: Sat Apr 08, 2023 5:11 pm

GPSrChive wrote: Fri Apr 07, 2023 12:26 am Looks like whatever software you used to convert the GPX or FIT file (you did not specify which) to KML format made some mistakes....

I downloaded the kml file via Garmin Connect on the website and opened it on my computer with Google Earth Pro. The interpolated line is the same as on Garmin Connect and on the device itself. So it is no mistake by the software. This happens not often, but it does happen also today on another hike. This contributes also, that afterwards it seems to be poorer the accuracy although the marks were ok.

Way too many conversions happening there to draw any conclusions.

Save the hike in GPX format on your device, and share that GPX file directly from the device, without running it through any software. This and this alone is the true indicator of the recorded track from the device, nothing else.

As indicated by others, the circles (dots) in your image are track points that have been 'filtered' by other software when reading and writing the file.

Thank you, that solved the problem with the strange interpolation.