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AR.relativeLocation, meaning of northing, easting ? directions

AR.relativeLocation, meaning of northing, easting ? directions



I am currently working on a location based app (using JS) and have a question concerning the class AR.RelativeLocation.

Does northing, easting etc. mean the real North, East etc. direction as the compass points to?  

Example: If I create a GeoLocation with parameters in Salzburg, Mirabell castle 

var castleLLA = new AR.GeoLocation(47.805403, 13.041763, 0);

and then a new relativeLocation with the following parameters:

var loc = new AR.RelativeLocation(castleLLA, -500, -1000, 1);

Does this mean, that the location "loc" is 500 m to the South, 1000 m to the West of Mirabell castle?  If the user is located directly at the castle and is looking with his device to the Northeast (real Northeast as indicated by the compass) , he will not see the model because it is placed to the Southwest. Is this correct? 

Concerning the altitude parameter, does the value 1 (of my example) mean : the model is placed at 1 m height = 1 m higher than the user's device? Or does it mean 1 m altitude as the compass app would show it?

Hope to hear from you, as it is really important to know this. 



Hi B. Terwe,


I expect the RelativeLocation object to behave as you detailed in your example.

Regarding altitude the former should be correct; a RelativeLocation with an altitude value of 1 should appear 1 meter above the referenced GeoLocation object.


Did you experience unexpected behaviour when you tried this?


Kind Regards


Hi Daniel,

Many thanks for your reply!

"Did you experience unexpected behaviour when you tried this?" - No, the altitude works as expected. I had confused metaio's and Wikitude's coordinate systems.  

But, I have 2 other questions concerning "AR.context.onLocationChanged": 


How is a location change checked, is there a kind of interval like each 500 milliseconds or similar?  

In my usecase, the user shall walk on foot. A 3D model shall update its position depending on the user?s location. 

I get a locationChanged event approx. every 5-12 seconds (or 15-20 steps) depending on the speed (m per second), the accuracy is about 2-3 m. I wish, I could get this event fired more often, in shorter intervals. 


Second problem is that the model disappears for a moment - it is not rendered. While debugging, this disappearing effect happens each time the function associated to ?World.locationChanged? is called, so in fact every 5-12 seconds when OnLocationChanged happens and the new LLA position for the model is computed.

Best regards,

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