Geopoint question reports high accuracy but point is in the ocean

What is the problem? Please be detailed.
I've heard from a couple of users (most recently @Joseph_E_Flack_IV) that they can sometimes capture geopoints that have high accuracy but impossible latitudes and longitudes. I have not been able to reproduce this myself. Users report that the same device and the same device type are successfully used in general. There seems to be no trend between locations where this happens -- rural vs urban, long time between point collection, etc. Android is set to capture points with GPS only.

What ODK tool and version are you using? And on what device and operating system version?
Any version of Collect. Devices are generally inexpensive field devices.

The discussion at Show satellites and time elapsed in geopoint dialog made me think there may be folks in the community who can explain this. Would some of the multi-point techniques described there help?

/CC @John_Ellis, @Ivangayton

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This is a tough one without knowing more details @Joseph_E_Flack_IV. @LN
Could you give me an example of the location in Lat and Long?
What is your hardware configuration?
Are you using a bluetooth GPS reciever or is it built in?

There are so many variables that could affect this, it is hard to speculate on the issue.

The CEP method would likely help, because you can collect multiple points and then throw out the ones that don't fall withing the circle where 50% of your locations occur for that recording. It is mainly used to throw out erroneous locations and increase confidence in the actual location. Raw averaging would not help unless you recorded enough locations to cancel out any erroneous locations that are VERY far away. This is assuming there is not an underlying driver issue for that specific GPS receiver. This can end up resulting in large numbers for CEP accuracy. So it may be also useful to average all of the points, remove out the furthest point or beyond a threshold from the average of all points. Then run CEP on the remaining points. This would filter out the Obvious errors, then only accept the most precise points.

One user I heard this from is in Northern Nigeria using the built-in GPS from Huawei 560s. They use other device types as well and the 560s are especially prone to bad points. Those devices also can sometimes take a really long time to get lock.

Yes, I'm not surprised! Thanks so much for the ideas.

I had the similar issue, but it was because the visualization map tools had read the latitude and longitude in reverse manner. I swapped the values in the CSV/kml and the issue was resolved

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That was actually one of the possibilities I was thinking about... This would be a hardware/system issue not an ODK issue per say.


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Apologies for not seeing this sooner. The details regarding the GPS issues we're experiencing at my organization are not known to myself, but I believe @James_Pringle @jpringle may be able to comment.