Comparing the level of accuracy of some GPS Enabled devices against the handheld GPS Receiver unit

Often times, during a training session, I get asked the question – ‘since our phones have GPS, why the need for this device?’ Over the years, I have consistently done this comparison test many times in the field in order to be sure I was still in tune with reality as technology improves every day.

What is my objective- To find out how accurate GPS enabled smartphones outfitted with location tracking software could be against the regular handheld GPS receiver unit?

My tools of the trade – a) a Blackberry Z10 running on Google AppSheet mobile location tracking app called ZipStore b) An IPhone running the ESRI proprietary ArcGIS Collector mobile App c) Garmin Dakota 20.

I wasn’t under any presumptions which was the best, so I went out quite sure the Garmin Dakota will better my GPS Enabled devices but the real question was how close or wide the margin will be for these smartphone devices.

Weather conditions– the sky was clear and marked a perfect day for a good mapping experience.

Methodology– at each location, I take the geographic coordinates of that point with each of the devices. The reading is taken on the same spot with each of the devices so there will be a sound basis for comparison. The locations chosen for the mapping have identifiable landmarks, are narrower than wide giving just enough room and margin to highlight the inaccuracies. Each device readings was then downloaded into google maps engine for visualization.

Results – See the embedded google image

Many of the points (shown as red markers) from the ZipStore app hosted on the blackberry Z10 fell off the mark into rather generalized positions. Surprisingly, Points captured using ESRI Collector (show in dark green actually showed a very fair degree of accuracy). While the points captured with the Garmin Dakota 20 when viewed on the imagery showed a near perfect match with the real locations, allowing it to basically serve as a control.

Conclusion– The handheld GPS gave a best showing as expected but the Esri Collector gave a great showing of itself, even rivaling the handheld at a good number of the locations. Esri Collector used base maps downloaded from ArcGIS Online while ZipStore used Bing maps.

Constraints– Most of the Smart phone location apps work with telecom networks for data as storage is cloud based. At location to3, Zip store on the Blackberry Z10 couldn’t acquire location while the Esri Collector started from point to3 downloads and couldn’t participate at to2 and to1 due to slow upload of the base map.

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