Geocaching for Science Fair - help/data needed

[Liz.]

Hi. I’m doing a Science Fair project about the accuracy of handheld GPS units and smartphones and which is better. I’m using geocaching as a way to gather data. I have been geocaching since I was about 2 and still cache randomly. I’m obtaining data for my project but could use some extra data.

 

It would be great to get some readings from cachers who could use both a smartphone and a handheld to geocache, but if you only use one or the other I could use that data too.

 

Data I’m looking for:

1. geocache name or code

2. what device(s) you used (brand, model) and what app for smartphone

3. difference between posted cords and your reading

4. weather conditions

5. any interference i.e. tree canopy, buildings

 

If you can help, please email your data to me through my profile by December 26th.

 

Thank you so much for your help!

 

(I have approval from my parents, SEWdaugh, and Groundspeak, Andrew, to post this in the forums)

[+kunarion]

Since you used the term "accuracy" when referring to the comparison between one GPSr's coordinates and another's, here's some good reading on the subject. Geocachers often say "accuracy" when they mean "precision". For a science project, your terms must be... accurate.

 

Good overview:

http://www.sage.unsw.edu.au/currentstudents/ug/projects/Allison/ACCURACY%20AND%20PRECISION.htm

 

Some heavy reading:

http://gpsworld.com/gnss-systemalgorithms-methodsinnovation-accuracy-versus-precision-9889/

Edited November 19, 2016 by kunarion

[+Touchstone]

Might be an interesting Event activity. Set up some objects in a park, and have people submit the coordinates and the device they were using. Could set up several waypoints/spots in various scenarios (i.e. under trees, clear sky view, inside a building or picnic shelter).

 

Good luck with your project!

[+egroeg]

You could also check to see if there are any USGS benchmarks nearby. Use various devices to determine coordinates there, then compare to the "official" coords.

[+Harry Dolphin]

You could also check to see if there are any USGS benchmarks nearby. Use various devices to determine coordinates there, then compare to the "official" coords.

 

Not all benchmarks have accurate coordinates. Some are accurate for elevation, Many have coords scaled from maps. A thirty or forty feet off is not unusual. I found one that was 1000 feet off.

For accurate coordinates, you would need a triangulation station disk.

[+gasbottle]

Take a look at https://coord.info/GCHQ2Y and https://coord.info/GC1CZ3B, both of which were set up to gather exactly this sort of data. You should be able to extract a couple of hundred useful data points from the logs. Searching for caches with 'accuracy' in the name might throw up a few more.

[+narcissa]

Get in touch with a local surveyor to help you get extremely precise and accurate coordinates for five sites around your area. Borrow a variety of devices from people you know, and use them at each site. Multiple visits will give you more data.

[+noncentric]

When considering the smartphones, you may want to consider the phones' settings. Most smartphones can be 'set' to use GPS sensors and/or cell/wifi signals when determining its location. A single phone may perform differently depending on whether it is set to use GPS+cellular+wifi vs if it is set to use GPS sensors only.

[+M 5]

My local group set up a teaching trail several years ago. The first cache on the trail might have some helpful information for you GC250JF

We had a local surveyor mark a point we had permission to place a post. Cachers are supposed to check their device at the post to see accuracy. I've noticed that if mine is off a certain direction/distance from the post on a particular day, that it is fairly consistent throughout the day of geocaching. Which tells me that it may be time of year/satelite positioning

[+Ben0w]

In Bavaria the surveyor authority now puts one reliable public surveyor mark per county. It's more or less a marketing thing, but the points are exact to a fraction of a centimeter (or an inch for you imperial folks). BTW some contain caches nearby (at least one IN the monument).

 

I tried my GPSr and my smartphone on two of those. Both showed the accurate readings.

 

When testing with geocaches you should take in account the capability of the cache owner to get sufficient coordinates. With consumer devices and not applying a lot of effort the cache position may have inaccuracies as well.

 

Additional disturbances are nearby structures or high landmarks, dense trees and rainy conditions. This applies tp both, GPSr and smartphone.

 

In my experience the key factor is not the tool you use, but the knowledge of sufficiently using that tool and about it's limitations in a given setting.

[+Harry Dolphin]

Liz.

.8 mile from your last find is a tringulation station disk NE1441. It's in a public park, and has several finds. Unless it's been moved, that will have very accurate cordinates.

[SEWdaugh]

Thanks to all who sent their data to my daughter, Liz. Please email your address through my profile with your choice of trackable(s) and I'll send them out.