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POIs drawn on wrong positions

Hello there,

we're experiencing an issue when showing geo-POIs of locations that are a few kilometers away.


Even though the GPS coordinates of the device are correct (even the altitude, which is around 412m - if this is relevant), the app seems to draw two of the key points too far away from eachother, which is clearly visible in the real world.


Here's a map preview of the coordinates in question, I have marked the user's location (north point) too: https://mint-media.hr/map.html


I will also attach a screenshot of the pins, and have marked their correct positions with red arrows. There is a slight compass error, but you can clearly see that the two pins would have to be moved by very different amounts to be on the correct position.


Please let us know if there are any steps we could take to fix this - I am 100% sure that we're passing the exact same coordinates to the app.



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Hi,


We're doing further investigations internally and will let you know via the ticket you created once we have feedback.


Greetings

Nicola

Hi Nicola,
I'm well aware that the compass isn't always correct, and I mentioned that in the post.
We event implement a form of optical calibration to address this, however the compass offset shouldn't affect the DISTANCE between two points, which greater then it should be in our case!

This is why I have drawn the red lines on the POIs.. If I was to move them to their correct positions, we would have to move them by different degrees -> meaning that there's something else beside the compass that isn't correct. I repeat, the GPS was very precise when the pic was taken.

Did you also check the coordintes of the user - are those always the corresponding correctly with the graphic that you shared of the map? If the user's location fix is off, this might also be a reason for the inaccurate positions.


Greetings

Nicola

Yes I did, the coordinates are within 1m accuracy, and we even did tests with manual coordinates set to these exact ones posted on the Google Map I gave.

Hi,


This seems like a compass issue - as we are dependent on the values the system is providing, it might sometimes happen that the values of the SDK change based on what the system returns. Can you check the compass values with a compass app.


As mentioned the SDK is dependant on the values received by system (e.g. compass values, Coordinates), so it can be that if the SDK recieves inaccurate values, that the POIs are not exactly where they are supposed to be.


Greetings

Nicola



Hi again!


Please check the exact coordinates of the user as well as the coordinates of the POIs.

Also, note that the vertical accuracy of GPS is usually way more off than the horizontal one. In case GPS places you 5m to the left, it may also lift you 25m higher than you actually are, which will then lead to offsets shown in your screenshot. Compass is a separate topic.


To keep it short: I recommend you to try at least 3 devices and observe their behavior. Try setting the user position to a fixed value and adjust altitude accordingly to then purely focus on the compass offset (of the devices).
You can then compare your values with the ones received from GPS / LocationProvider to figure out where the real issue is.


Best regards,

Andreas

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