Re: [Texascavers] Notes on GPS, GNSS, and GIS for Cavers

[William R. Elliott]

OK, Diana, I'll summarize what I know about GPS units. I don't own a Garmin
or Magellan handheld unit any more, just the Bad Elf GPS Pro.

Probably some of the more expensive GPS units have slightly better location
accuracy (repeatability or trueness). Precision is different, it's how fine
the location is presented, say ±3.0 m vs. 3.1 m. I am always skeptical of
accuracy and precision claims, so I prefer to see some test data with the
conditions stated.

These are arranged from less to more expensive, generally:

iPhone 3G w/ cellular positioning ~±600 m [Zandbergen 2009 study, see
source below]
iPhone 3G w/ wifi ~±74 m [Zandbergen 2009 study]
iPhone 3G w/ A-GPS ~±8 m [Zandbergen 2009 study]
Android smart phones, 2009, ±5-8 m [Zandbergen 2009 study]
*iPhone 4S and current models, ±30 m with Compass app, ±10 m with Compass
55 app [Elliott tests w/ iPad mini 2 and iPhone 6.]*
Qstarz (racing GPS with Bluetooth), ±3 m [their website]
Garmin, many models, ±3 m? [Internet blogs, some users claim better than
this with waypoint averaging]
Bad Elf GPS Pro, ±2.5 m but mine usually is ±4 m [Elliott tests]
Bad Elf GPS Pro+, ±2.0 m [their website]
Bad Elf GNSS Surveyor, ±1 m [their website]
Arrow Lite, ±1 m [Internet blogs]
Arrow 100, ±0.1 m (1 cm) [Internet blogs]

*Sources*
https://communityhealthmaps.nlm.nih.gov/2014/07/07/how-accurate-is-the-gps-on-my-smart-phone-part-2/

https://itstillworks.com/accurate-iphone-gps-18419.html

All in all, ±3 m accuracy is pretty good for rough field surveys. Tying two
caves together really deserves ±1 m accuracy or better, or just a high
quality overland survey, but that has its errors too. Pinpointing wells,
benchmarks, property boundaries, etc. requires professional surveyors
and/or two professional GPS units with a base station and roaming unit.

Cavers, you can test your own GPS by sitting in a folding chair in your
back yard, or better, in the middle of a field away from trees. If you can
find an official benchmark with the location known to 0.1" or 0.1
degrees, that would be good to test, but it might not be in a good spot to
safely do this. Keep the receiver stationary and don't block it with your
own body. Might be better to put it on a table or hang it from a tripod
handle away from the head. Periodically write down the time, position
errors, decimal degrees to 5 or 6 decimals, and how many SVs (satellite
vehicles) are in view. Horizontal position is usually the least variable.
Average these values. All of this varies with clouds, satellites in view,
time of day, the ionosphere, etc.  Feel free to post your results here for
discussion. Be sure to tell us the model of your device.

Thanks,

*William R. (Bill) Elliott*

*speodes...@gmail.com *

573-291-5093 cell


On Thu, Sep 27, 2018 at 1:35 PM Diana Tomchick <
diana.tomch...@utsouthwestern.edu> wrote:

> Ah, yes, +/- 3 meters accuracy is pretty good for a cave entrance
> location, and is useful for following a track log.
>
> +/- 10 meters accuracy can be pretty frustrating for a cave entrance
> location, however, especially if the entrance isn’t very large, there’s a
> lot of underbrush or tree cover, and the terrain is quite rugged. And
> that’s the accuracy of an iPhone using the built-in Compass app.
>
> Diana
>
> **
> Diana R. Tomchick
> Professor
> Departments of Biophysics and Biochemistry
> University of Texas Southwestern Medical Center
> 5323 Harry Hines Blvd.
> Rm. ND10.214A
> Dallas, TX 75390-8816
> diana.tomch...@utsouthwestern.edu
> (214) 645-6383 (phone)
> (214) 645-6353 (fax)
>
> On Sep 27, 2018, at 1:30 PM, Geary Schindel 
> wrote:
>
> One of the other issues you need to look at is what you’re doing with the
> data and how valuable it is to you. if you’re surveying a monitoring well
> network and have a flat water table, you may need to know the position of
> the measuring point to within 0.01 foot horizontally and vertically
> (vertically is much more difficult to get good data). If so, you need to
> use surveyor grade GPS systems and a licensed surveyor. However, sometimes
> even that won’t work. (Buy me a beer sometime and I’ll tell you the story
> of the $60 million survey error by an RLS resulting in four years of
> litigation.)
>
> If you are just trying to be able to relocate something in the field that
> is pretty unique like a cave entrance or spring, maybe 3 meters accuracy is
> good enough and a hand held GPS unit would be fine. So, depends upon what
> your trying to map or record.
>
> Bill, excellent article and thanks for sharing.
>
> Geary Schindel
> gschin...@edwardsaquifer.org
>
>
>
>
> *From:* Texascavers  *On Behalf Of *Diana
> Tomchick
> *Sent:* Thursday, September 27, 2018 12:51 PM
> *To:* Cave Tex 
> *Subject:* Re: [Texascavers] Notes on GPS, GNSS, and GIS for Cavers
>
> I think the best take-home message in your PDF is the accuracy for a cell
> phone or tablet can vary depending upon not only the device but also upon
> the software 

Re: [Texascavers] Notes on GPS, GNSS, and GIS for Cavers

[Diana Tomchick]

Ah, yes, +/- 3 meters accuracy is pretty good for a cave entrance location, and 
is useful for following a track log.

+/- 10 meters accuracy can be pretty frustrating for a cave entrance location, 
however, especially if the entrance isn’t very large, there’s a lot of 
underbrush or tree cover, and the terrain is quite rugged. And that’s the 
accuracy of an iPhone using the built-in Compass app.

Diana

**
Diana R. Tomchick
Professor
Departments of Biophysics and Biochemistry
University of Texas Southwestern Medical Center
5323 Harry Hines Blvd.
Rm. ND10.214A
Dallas, TX 75390-8816
diana.tomch...@utsouthwestern.edu
(214) 645-6383 (phone)
(214) 645-6353 (fax)

On Sep 27, 2018, at 1:30 PM, Geary Schindel 
mailto:gschin...@edwardsaquifer.org>> wrote:

One of the other issues you need to look at is what you’re doing with the data 
and how valuable it is to you. if you’re surveying a monitoring well network 
and have a flat water table, you may need to know the position of the measuring 
point to within 0.01 foot horizontally and vertically (vertically is much more 
difficult to get good data). If so, you need to use surveyor grade GPS systems 
and a licensed surveyor. However, sometimes even that won’t work. (Buy me a 
beer sometime and I’ll tell you the story of the $60 million survey error by an 
RLS resulting in four years of litigation.)

If you are just trying to be able to relocate something in the field that is 
pretty unique like a cave entrance or spring, maybe 3 meters accuracy is good 
enough and a hand held GPS unit would be fine. So, depends upon what your 
trying to map or record.

Bill, excellent article and thanks for sharing.

Geary Schindel
gschin...@edwardsaquifer.org




From: Texascavers 
mailto:texascavers-boun...@texascavers.com>>
 On Behalf Of Diana Tomchick
Sent: Thursday, September 27, 2018 12:51 PM
To: Cave Tex mailto:texascavers@texascavers.com>>
Subject: Re: [Texascavers] Notes on GPS, GNSS, and GIS for Cavers

I think the best take-home message in your PDF is the accuracy for a cell phone 
or tablet can vary depending upon not only the device but also upon the 
software used.

A useful addition to the PDF would be a table that lists the estimated accuracy 
for different devices that people actually use in the field, including handheld 
consumer GPS units, cell phones, Bad Elf, etc.

I know the information is in the PDF, but having a table that collects all the 
information together would be extremely useful, especially when one needs and 
easy and quick way to explain to someone why using their internal Compass app 
on an iPhone isn’t as accurate as a handheld consumer GPS unit.

Diana

**
Diana R. Tomchick
Professor
Departments of Biophysics and Biochemistry
University of Texas Southwestern Medical Center
5323 Harry Hines Blvd.
Rm. ND10.214A
Dallas, TX 75390-8816
diana.tomch...@utsouthwestern.edu
(214) 645-6383 (phone)
(214) 645-6353 (fax)

On Sep 27, 2018, at 11:23 AM, William R. Elliott 
mailto:speodes...@gmail.com>> wrote:

Diana,

I looked up what I could about iPhone XS Location. All Apple said was this:

Assisted GPS, GLONASS, Galileo, and QZSS
Digital compass [apparently the same old Compass app]
Wi‑Fi
Cellular
iBeacon microlocation [used indoors at stores via Bluetooth)

So, we don't know if the accuracy has been improved. With the same old Compass 
app, the precision is cut off at one second, about ±30 m. As I mentioned in my 
article, get the free Compass 55 app and you'll achieve a precision of ±0.1 
degree, or about ±1m, but that's not the same as the phone's accuracy, which 
may only be ±10 m.

I've found that if you ask a salesman about these things they'll give you 
anecdotal information or a guess. They often brag about how the phone uses cell 
towers to improve its accuracy, but that's not what we want out in the wild. 
Good luck!
William R. (Bill) Elliott
speodes...@gmail.com
573-291-5093 cell


On Thu, Sep 27, 2018 at 10:45 AM Diana Tomchick 
mailto:diana.tomch...@utsouthwestern.edu>> 
wrote:
I would be curious to know the accuracy of the latest iPhoneXS models.

Diana

**
Diana R. Tomchick
Professor
Departments of Biophysics and Biochemistry
University of Texas Southwestern Medical Center
5323 Harry Hines Blvd.
Rm. ND10.214A
Dallas, TX 75390-8816
diana.tomch...@utsouthwestern.edu
(214) 645-6383 (phone)
(214) 645-6353 (fax)

On Sep 26, 2018, at 11:01 PM, William R. Elliott 
mailto:speodes...@gmail.com>> wrote:

Attached is a pdf article I wrote for the Texas Cavers list.

Here are some notes on tablets, cell phones, GPS (Global Positioning System), 
and apps that cavers might use for cave projects, especially apps that are 

Re: [Texascavers] Notes on GPS, GNSS, and GIS for Cavers

[Geary Schindel]

One of the other issues you need to look at is what you’re doing with the data 
and how valuable it is to you. if you’re surveying a monitoring well network 
and have a flat water table, you may need to know the position of the measuring 
point to within 0.01 foot horizontally and vertically (vertically is much more 
difficult to get good data). If so, you need to use surveyor grade GPS systems 
and a licensed surveyor. However, sometimes even that won’t work. (Buy me a 
beer sometime and I’ll tell you the story of the $60 million survey error by an 
RLS resulting in four years of litigation.)

If you are just trying to be able to relocate something in the field that is 
pretty unique like a cave entrance or spring, maybe 3 meters accuracy is good 
enough and a hand held GPS unit would be fine. So, depends upon what your 
trying to map or record.

Bill, excellent article and thanks for sharing.

Geary Schindel
gschin...@edwardsaquifer.org




From: Texascavers  On Behalf Of Diana 
Tomchick
Sent: Thursday, September 27, 2018 12:51 PM
To: Cave Tex 
Subject: Re: [Texascavers] Notes on GPS, GNSS, and GIS for Cavers

I think the best take-home message in your PDF is the accuracy for a cell phone 
or tablet can vary depending upon not only the device but also upon the 
software used.

A useful addition to the PDF would be a table that lists the estimated accuracy 
for different devices that people actually use in the field, including handheld 
consumer GPS units, cell phones, Bad Elf, etc.

I know the information is in the PDF, but having a table that collects all the 
information together would be extremely useful, especially when one needs and 
easy and quick way to explain to someone why using their internal Compass app 
on an iPhone isn’t as accurate as a handheld consumer GPS unit.

Diana

**
Diana R. Tomchick
Professor
Departments of Biophysics and Biochemistry
University of Texas Southwestern Medical Center
5323 Harry Hines Blvd.
Rm. ND10.214A
Dallas, TX 75390-8816
diana.tomch...@utsouthwestern.edu
(214) 645-6383 (phone)
(214) 645-6353 (fax)

On Sep 27, 2018, at 11:23 AM, William R. Elliott 
mailto:speodes...@gmail.com>> wrote:

Diana,

I looked up what I could about iPhone XS Location. All Apple said was this:

Assisted GPS, GLONASS, Galileo, and QZSS
Digital compass [apparently the same old Compass app]
Wi‑Fi
Cellular
iBeacon microlocation [used indoors at stores via Bluetooth)

So, we don't know if the accuracy has been improved. With the same old Compass 
app, the precision is cut off at one second, about ±30 m. As I mentioned in my 
article, get the free Compass 55 app and you'll achieve a precision of ±0.1 
degree, or about ±1m, but that's not the same as the phone's accuracy, which 
may only be ±10 m.

I've found that if you ask a salesman about these things they'll give you 
anecdotal information or a guess. They often brag about how the phone uses cell 
towers to improve its accuracy, but that's not what we want out in the wild. 
Good luck!
William R. (Bill) Elliott
speodes...@gmail.com
573-291-5093 cell


On Thu, Sep 27, 2018 at 10:45 AM Diana Tomchick 
mailto:diana.tomch...@utsouthwestern.edu>> 
wrote:
I would be curious to know the accuracy of the latest iPhoneXS models.

Diana

**
Diana R. Tomchick
Professor
Departments of Biophysics and Biochemistry
University of Texas Southwestern Medical Center
5323 Harry Hines Blvd.
Rm. ND10.214A
Dallas, TX 75390-8816
diana.tomch...@utsouthwestern.edu
(214) 645-6383 (phone)
(214) 645-6353 (fax)

On Sep 26, 2018, at 11:01 PM, William R. Elliott 
mailto:speodes...@gmail.com>> wrote:

Attached is a pdf article I wrote for the Texas Cavers list.

Here are some notes on tablets, cell phones, GPS (Global Positioning System), 
and apps that cavers might use for cave projects, especially apps that are free 
or not too pricey. GPS and GIS (Geographic Information System) are my sub-hobby 
within caving. I recently experimented with the Bad Elf GPS Pro and a Windows 
tablet among other things. The procedures to make these things work together 
are not completely spelled out in the user manuals, so I had to figure things 
out by testing. New devices are coming on the market. Maybe this article will 
save readers some time, and I welcome discussion of these topics.

Thanks, see y'all at TCR,
William R. (Bill) Elliott
speodes...@gmail.com
573-291-5093 cell
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UT 

Re: [Texascavers] Notes on GPS, GNSS, and GIS for Cavers

[Diana Tomchick]

I think the best take-home message in your PDF is the accuracy for a cell phone 
or tablet can vary depending upon not only the device but also upon the 
software used.

A useful addition to the PDF would be a table that lists the estimated accuracy 
for different devices that people actually use in the field, including handheld 
consumer GPS units, cell phones, Bad Elf, etc.

I know the information is in the PDF, but having a table that collects all the 
information together would be extremely useful, especially when one needs and 
easy and quick way to explain to someone why using their internal Compass app 
on an iPhone isn’t as accurate as a handheld consumer GPS unit.

Diana

**
Diana R. Tomchick
Professor
Departments of Biophysics and Biochemistry
University of Texas Southwestern Medical Center
5323 Harry Hines Blvd.
Rm. ND10.214A
Dallas, TX 75390-8816
diana.tomch...@utsouthwestern.edu
(214) 645-6383 (phone)
(214) 645-6353 (fax)

On Sep 27, 2018, at 11:23 AM, William R. Elliott 
mailto:speodes...@gmail.com>> wrote:

Diana,

I looked up what I could about iPhone XS Location. All Apple said was this:

Assisted GPS, GLONASS, Galileo, and QZSS
Digital compass [apparently the same old Compass app]
Wi‑Fi
Cellular
iBeacon microlocation [used indoors at stores via Bluetooth)

So, we don't know if the accuracy has been improved. With the same old Compass 
app, the precision is cut off at one second, about ±30 m. As I mentioned in my 
article, get the free Compass 55 app and you'll achieve a precision of ±0.1 
degree, or about ±1m, but that's not the same as the phone's accuracy, which 
may only be ±10 m.

I've found that if you ask a salesman about these things they'll give you 
anecdotal information or a guess. They often brag about how the phone uses cell 
towers to improve its accuracy, but that's not what we want out in the wild. 
Good luck!

William R. (Bill) Elliott

speodes...@gmail.com

573-291-5093 cell


On Thu, Sep 27, 2018 at 10:45 AM Diana Tomchick 
mailto:diana.tomch...@utsouthwestern.edu>> 
wrote:
I would be curious to know the accuracy of the latest iPhoneXS models.

Diana

**
Diana R. Tomchick
Professor
Departments of Biophysics and Biochemistry
University of Texas Southwestern Medical Center
5323 Harry Hines Blvd.
Rm. ND10.214A
Dallas, TX 75390-8816
diana.tomch...@utsouthwestern.edu
(214) 645-6383 (phone)
(214) 645-6353 (fax)

On Sep 26, 2018, at 11:01 PM, William R. Elliott 
mailto:speodes...@gmail.com>> wrote:

Attached is a pdf article I wrote for the Texas Cavers list.

Here are some notes on tablets, cell phones, GPS (Global Positioning System), 
and apps that cavers might use for cave projects, especially apps that are free 
or not too pricey. GPS and GIS (Geographic Information System) are my sub-hobby 
within caving. I recently experimented with the Bad Elf GPS Pro and a Windows 
tablet among other things. The procedures to make these things work together 
are not completely spelled out in the user manuals, so I had to figure things 
out by testing. New devices are coming on the market. Maybe this article will 
save readers some time, and I welcome discussion of these topics.

Thanks, see y'all at TCR,

William R. (Bill) Elliott

speodes...@gmail.com

573-291-5093 cell

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Re: [Texascavers] paper maps vs. digital maps

[Charles Loving]

They worked quite well in Algeria between Bechar and Agades. ONC charts
kept us from becoming fossils.

On Thu, Sep 27, 2018 at 11:57 AM William R. Elliott 
wrote:

> In reply to the joking comment that paper maps are better, well maybe if
> you live in the Jurassic Period. Try to find paper topo maps any more. We
> used to buy them at Miller Blueprint in Austin, but they were not cheap,
> and they were limited in coverage. I guess that TSS still has vast files of
> topo maps--I used to catalog them. Cavers used to make special trips to
> Mexico City to buy topo maps. Now you can download them.
>
> Imagine the floor of a convention hall covered with topo maps or quads,
> all properly tiled with the collars (white edges) cut off. Then imagine a
> GPS location displayed on this as a point of light that moves as the
> receiver moves. You can do all of that virtually on your tablet or phone
> now. And the maps are mostly free. You can take a whole library of them
> with you on your device.
>
> However, if you want to see some paper maps I produced, get *The Astyanax
> Caves of Mexico*, AMCS Bulletin 26, at TCR. The many cave maps, area
> maps, and the large, folded El Abra Regional map, were built using Walls,
> WallsMap, QGIS, and illustration programs. The area maps have footprints of
> the caves generated in Walls and sent over to WallsMap. The book is quite
> usable in the field. And there even are photos of Jurassic Period cavers on
> p. 178 and many other pages.
>
> This morning I posted the El Abra Regional map on
> http://cavelife.info/Astyanax/Astyanax.htm  It is 56 MB, and you can view
> it in fine detail. The 10" x 29.5" paper map comes with the book.
>
> On that same cavelife page I also posted my *GPS article* and *Appendix
> 5. How to Obtain Mexican Maps*, from the book.
>
> Happy topo maps!
>
> Living fossil from the Cretaceous Period...
>
> *William R. (Bill) Elliott*
>
> *speodes...@gmail.com *
>
> 573-291-5093 cell
> ___
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> http://www.mail-archive.com/texascavers@texascavers.com/
> http://lists.texascavers.com/listinfo/texascavers
>


-- 
Charlie Loving
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[Texascavers] paper maps vs. digital maps

[William R. Elliott]

In reply to the joking comment that paper maps are better, well maybe if
you live in the Jurassic Period. Try to find paper topo maps any more. We
used to buy them at Miller Blueprint in Austin, but they were not cheap,
and they were limited in coverage. I guess that TSS still has vast files of
topo maps--I used to catalog them. Cavers used to make special trips to
Mexico City to buy topo maps. Now you can download them.

Imagine the floor of a convention hall covered with topo maps or quads, all
properly tiled with the collars (white edges) cut off. Then imagine a GPS
location displayed on this as a point of light that moves as the receiver
moves. You can do all of that virtually on your tablet or phone now. And
the maps are mostly free. You can take a whole library of them with you on
your device.

However, if you want to see some paper maps I produced, get *The Astyanax
Caves of Mexico*, AMCS Bulletin 26, at TCR. The many cave maps, area maps,
and the large, folded El Abra Regional map, were built using Walls,
WallsMap, QGIS, and illustration programs. The area maps have footprints of
the caves generated in Walls and sent over to WallsMap. The book is quite
usable in the field. And there even are photos of Jurassic Period cavers on
p. 178 and many other pages.

This morning I posted the El Abra Regional map on
http://cavelife.info/Astyanax/Astyanax.htm  It is 56 MB, and you can view
it in fine detail. The 10" x 29.5" paper map comes with the book.

On that same cavelife page I also posted my *GPS article* and *Appendix 5.
How to Obtain Mexican Maps*, from the book.

Happy topo maps!

Living fossil from the Cretaceous Period...

*William R. (Bill) Elliott*

*speodes...@gmail.com *

573-291-5093 cell
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Re: [Texascavers] Notes on GPS, GNSS, and GIS for Cavers

[William R. Elliott]

Diana,

I looked up what I could about iPhone XS Location. All Apple said was this:

Assisted GPS, GLONASS, Galileo, and QZSS
Digital compass [apparently the same old Compass app]
Wi‑Fi
Cellular
iBeacon microlocation [used indoors at stores via Bluetooth)

So, we don't know if the accuracy has been improved. With the same old
Compass app, the precision is cut off at one second, about ±30 m. As I
mentioned in my article, get the free Compass 55 app and you'll achieve a
precision of ±0.1 degree, or about ±1m, but that's not the same as the
phone's accuracy, which may only be ±10 m.

I've found that if you ask a salesman about these things they'll give you
anecdotal information or a guess. They often brag about how the phone uses
cell towers to improve its accuracy, but that's not what we want out in the
wild. Good luck!

*William R. (Bill) Elliott*

*speodes...@gmail.com *

573-291-5093 cell


On Thu, Sep 27, 2018 at 10:45 AM Diana Tomchick <
diana.tomch...@utsouthwestern.edu> wrote:

> I would be curious to know the accuracy of the latest iPhoneXS models.
>
> Diana
>
> **
> Diana R. Tomchick
> Professor
> Departments of Biophysics and Biochemistry
> University of Texas Southwestern Medical Center
> 5323 Harry Hines Blvd.
> Rm. ND10.214A
> Dallas, TX 75390-8816
> diana.tomch...@utsouthwestern.edu
> (214) 645-6383 (phone)
> (214) 645-6353 (fax)
>
> On Sep 26, 2018, at 11:01 PM, William R. Elliott 
> wrote:
>
> Attached is a pdf article I wrote for the Texas Cavers list.
>
> Here are some notes on tablets, cell phones, GPS (Global Positioning
> System), and apps that cavers might use for cave projects, especially apps
> that are free or not too pricey. GPS and GIS (Geographic Information
> System) are my sub-hobby within caving. I recently experimented with the
> Bad Elf GPS Pro and a Windows tablet among other things. The procedures to
> make these things work together are not completely spelled out in the user
> manuals, so I had to figure things out by testing. New devices are coming
> on the market. Maybe this article will save readers some time, and I
> welcome discussion of these topics.
>
> Thanks, see y'all at TCR,
>
> *William R. (Bill) Elliott*
>
> *speodes...@gmail.com *
>
> 573-291-5093 cell
> 
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>
>
> --
>
> UT Southwestern
>
> Medical Center
>
> The future of medicine, today.
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>
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Re: [Texascavers] Notes on GPS, GNSS, and GIS for Cavers

[Diana Tomchick]

I would be curious to know the accuracy of the latest iPhoneXS models.

Diana

**
Diana R. Tomchick
Professor
Departments of Biophysics and Biochemistry
University of Texas Southwestern Medical Center
5323 Harry Hines Blvd.
Rm. ND10.214A
Dallas, TX 75390-8816
diana.tomch...@utsouthwestern.edu
(214) 645-6383 (phone)
(214) 645-6353 (fax)

On Sep 26, 2018, at 11:01 PM, William R. Elliott 
mailto:speodes...@gmail.com>> wrote:

Attached is a pdf article I wrote for the Texas Cavers list.

Here are some notes on tablets, cell phones, GPS (Global Positioning System), 
and apps that cavers might use for cave projects, especially apps that are free 
or not too pricey. GPS and GIS (Geographic Information System) are my sub-hobby 
within caving. I recently experimented with the Bad Elf GPS Pro and a Windows 
tablet among other things. The procedures to make these things work together 
are not completely spelled out in the user manuals, so I had to figure things 
out by testing. New devices are coming on the market. Maybe this article will 
save readers some time, and I welcome discussion of these topics.

Thanks, see y'all at TCR,

William R. (Bill) Elliott

speodes...@gmail.com

573-291-5093 cell

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UT Southwestern


Medical Center



The future of medicine, today.

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Re: [Texascavers] Notes on GPS, GNSS, and GIS for Cavers

[Mark Minton]

Bill,


Thanks for the info on GPS, GIS, etc. For the past couple of years, Tommy 
Shifflett has been using the Bad Elf GPS unit to get accurate entrance 
locations in the Huautla area. He has been quite satisfied with the results. 
See his articles in AMCS Activities Newsletter 37, p. 67, 2016, NSS News 
74(12), p. 10, December 2016 and NSS News 75(12), p. 31, December 2017.


Mark Minton
mmin...@caver.net


On Thu, 27 Sep, 2018 at 12:02 AM, William R. Elliott  
wrote:
 




Attached is a pdf article I wrote for the Texas Cavers list.


Here are some notes on tablets, cell phones, GPS (Global Positioning System), 
and apps that cavers might use for cave projects, especially apps that are free 
or not too pricey. GPS and GIS (Geographic Information System) are my sub-hobby 
within caving. I recently experimented with the Bad Elf GPS Pro and a Windows 
tablet among other things. The procedures to make these things work together 
are not completely spelled out in the user manuals, so I had to figure things 
out by testing. New devices are coming on the market. Maybe this article will 
save readers some time, and I welcome discussion of these topics. 



Thanks, see y'all at TCR,





William R. (Bill) Elliott


speodes...@gmail.com
573-291-5093 cell ___
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