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What, definitively, does the blue accuracy ring show in Collector. In the field it always seems too large to represent the accuracy that the GNSS app is stating (ie 50cm – 1m). The blue ring seems to be closer to 30 ft. It could be that Collector doesn’t know what to do with the GNSS accuracy yet or just shows a different, more conservative confidence interval. I was just wondering if Collector is taking full advantage of the GNSS sub-meter accuracy. Perhaps Collector does not take into account the Real-time correction using SBAS?

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Collector will utilize the GNSS positional data provided by the GNSS (any real-time correction..SBAS, RTK, etc.). I have used the Leica Zeno 20 with Collector and can confirm that this configuration is providing 1cm level accuracy when storing features within the Collector app. As for the blue ring and how it relates to the accuracy of the solution, I am not certain.

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From my experience, the ring is larger in areas with more interference, etc. Using Collector in an open field, my location is pretty spot on. If there are a lot of buildings, power lines or other items that may interfere with the signal, the ring is larger and points are close, but not necessarily on target.

  • I understand that GPS "does not work" inside or near buildings due to interference. However, I am interested int he interpretation of the blue ring around the point - is this a visualization of the range of error? Is it meaningless? The blue ring, whether I am in a building or not, does not seem to adjust to my accuracy. As I zoom in and out, the ring stays a relative diameter on the screen, but then it covers a different amound of "space" in the map scale. So, does it represent accuracy - probably not. But what does it represent? – Stella Dec 30 '15 at 16:36
  • "The blue dot with the blue circle around it represents your location as the iPad can determine, and the blue circle represents the perceived accuracy of that location. " From dot.state.mn.us/bridge/hydraulics/culvertcost/… It appears that that outer ring is based upon your devices location. – MaryBeth Dec 30 '15 at 19:24
  • Now what if the GPS device paired with the app reads an accuracy of .5m, but the blue ring shows 30m? – Stella Dec 31 '15 at 0:48

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