[HOT] Feedback about smartphones use for OSM field surveys

Stéphane Henriod s at henriod.info
Wed Jun 13 08:07:46 BST 2012


Hi

I would be interested to know how you would rate external data loggers
against "classical" Garmin eTrex or similar devices?

On the + side of the eTrex-like I see:

   - More robust and usually better chip than smartphones (but probably
   similar to data loggers' chips)
   - GPS chip and map on the same device (unlike data loggers)
   - Relatively good battery life (with my eTrex 20 I can easily record for
   a full day. And if I'm somewhere without power outlets, I just take a few
   extra batteries)
   - OSM (or other) data can be displayed as background, which makes it
   much easier to see "live" what has already been mapped, what hasn't, and
   what can be corrected
   - Coupling GPS and GLONASS can significantly improve the reception in
   some areas

On the - side:

   - Real pain in the ass when it comes to log polygons (= closed ways)
   - Real pain in the ass (2) to type in waypoints names (a sheet of paper
   is always better for that)

On the + side of the data loggers:

   - Extremely compact
   - Best battery life
   - Cheap

But on the - side:

   - Needs a second device to visualize tracks and background data
   - If paired with another device through bluetooth, this will vastly
   reduce the batterylife (at least for the 2nd device)

Now, have you seen significant difference in positional accuracy between
such data logger and eTrex-like devices? I am so far very happy with my
eTrex20 (and thus with SIRF III, despite your warning... would be
interested to read why you warn against it?)

Cheers,

Stéphane
--
"Le mot progrès n'aura aucun sens tant qu'il y aura des enfants malheureux"
-- Albert Einstein

"A journey does not need reasons. Before long, it proves to be reason
enough in itself. One thinks that one is going to make a journey, yet soon
it is the journey that makes or unmakes you." -- Nicolas Bouvier

Photos de voyages, photos de montagne: http://www.henriod.info



On Wed, Jun 13, 2012 at 2:10 AM, Boris Cornet <borisC at osm-at.org> wrote:

> Hi!
>
> As Victor said, there are huge advantages with external devices:
> - power efficiency
> - small size (and yes, it makes a lot of difference where you carry a
>  GPS device, cap is best, shoulder is 2nd best)
> - bluetooth works with any device that is bluetooth enabled on merely
>  every OS since GPS loggers use a standard bluetooth protocol
>  (RFComm) and send standardized data (NMEA-0183).
> - the chipset matters a lot: lookout for UBlox 5 (best) or MTK 2
>  (2nd best), beware of sirf3 (!!!)
> - also the antenna matters: smartphones care for the phone antenna,
>  the GPS antenna must stand back.
>
> I use the Wintec WBT 202, and I can confirm that it is far better than
> every smartphone I could test. The difference is not so obvious in
> normal conditions, but when things get rough (e.g. badly positioned
> satellites, high buildings, trees) the data collected by smartphones
> is almost unusable, while the logger still produces reasonable
> results.
>
> Today (Tuesday, June 12, 2012) at 23:44 Victor Ferreira noted:
> > Hi,
> > one advantage of data loggers (i use Qstarz 1000 for recording
> > tracks to upload to OSM) is that they are very energy eficient, and
> > they do not need any other device for recording the tracks. My
> > Qstarz easily goes on for 24h recording (or that amount of hours, in
> > diferent days), anf if not on, the battery lasts for weeks without
> > needing a recharge (very good in places without power outlets!).
> >   But some of them also provide the possibility of being used in
> > realtime with bluetooth (qstarz work well with linux and windows at
> > least - android and iphone i do not know...).
> > The acuracy of all this devices are from 3meters to 10 meters,
> > dependin on satellite configuration and obstacules (buildings or
> > tree cover). After testing the data loggers in diferent positions on
> > the body, i found out that the best results where when i used it
> > hanging on my cap with a safety pin (since it is very small, no one
> > seems to notice the strange guy with a gps hanging from his head
> > hehe). It maximizes the exposure to the sky, wherethe satellites are!
> >
> > Any better you should really look at professional GPS and maybe some
> good antenna.
> > Maybe you can find some second hand equipment?
> > Regards,
> > Victor Ferreira
>
> > On Tue, Jun 12, 2012 at 2:57 PM, Banick, Robert
> > <Robert.Banick at redcross.org> wrote:
> >
> >
> >
> >
> > Hi Chuck,
> >
> >
> >
> > We used the Dual units while walking around a neighborhood of Lima.
> > It was in the southern hemisphere, obviously, but there were few
> > tall buildings to distort  the signal. As a preliminary test we were
> > mostly interested in using the smartphones for visualization and
> > data logging, though on the fly editing is certainly a nice to have.
> > Our primary motive is actually to combine our evaluation
> > (non-geographic data collection)  and GIS surveying activities in
> > one package using smartphones. A number of apps exist at present to
> > enable this, but we’re concerned that the base accuracy for most
> > smartphone GPS units makes them rather unreliable – hence the external
> units.
> >
> >
> >
> > We were getting 3-6 meters of accuracy with the Dual units in Lima,
> > readings that were confirmed by the accuracy of the data when later
> uploaded.
> >
> >
> >
> > I’d be interested in your thoughts on the other external units. We
> > went with the Dual units because they’re purpose built to interact
> > with smartphones (iPhones,  unfortunately), but I’d be interested if
> > the data loggers you mention could do a better job.
> >
> >
> >
> > Cheers,
> >
> > Robert
> >
> >
> >
> >
> >
> >
> >
> > Robert Banick | GIS Coordinator | International Services | Ì American
> Red Cross
> >
> > 2025 E Street NW, Washington, DC 20006
> >
> > Tel 202-303-5017 | Cell 404-964-3451 | Fax 202-303—052 | Skype
> robert.banick
> >
> >
> >
> > From: Charles Conley [mailto:cconley at immap.org]
> >  Sent: Monday, June 11, 2012 1:52 PM
> >  To: hot at openstreetmap.org
> >  Subject: [HOT] Feedback about smartphones use for OSM field surveys
>
> >
> >
> >
> > Hello All,
> >  I wanted to ask a couple of questions and perhaps contribute a
> > little to the discussion on external GPS use.
> >
> >  The first item I wanted to ask about is the notion of accuracy.
> > I'm not clear if the positional accuracy of an external bluetooth
> > GPS is any greater than the accuracy of a smartphone GPS. The
> > research I found on the net seemed to be focused more on comparing
> > traditional handheld GPS units to smartphones. I'm not sure if these
> > comparisons are valid given that most of the external bluetooth
> > units have more in common with GPS data loggers than they do with
> > handhelds. Has anyone here done any testing to determine  if there
> > is a difference in accuracy between the data logger type of GPS and
> smartphone GPS?
> >
> >  Robert could you please add a bit more detail on the scenario that
> > the BT units were used? Specifically I'm interested in understanding
> > if they were used while walking or from a car or an aircraft. Was
> > the intent to allow for data editing on the fly or just  using the
> > smartphone for visualization and data logging?
> >
> >  I'm asking because we have used several external GPS units similar
> > to the one that was mentioned. The units we used were the Qstarz
> > BT-Q1000eX. We did not use the BT feature of these units but rather
> > used them as highspeed data loggers to collect the path of
> > high-voltage power lines from a helicopter. We chose these
> > particular units because they would allow us to collect up to 10
> > points a second. Another interesting unit is the GiSTEQ DL500. The
> > DL500 doesn't have bluetooth but it does allow for logging up to  5
> > points a second and more interestingly is also has a 3 axis
> > accelerometer that would allow for determining a measure of road
> roughness.
> >
> >  Best wishes
> >
> >  Chuck
> >
> >
> >
> >
> >
> > ------------------------------
> >
> >  Message: 2
> >  Date: Sun, 10 Jun 2012 23:48:40 +0000
> >  From: "Banick, Robert" <Robert.Banick at redcross.org>
> >  To: "hot at openstreetmap.org" <hot at openstreetmap.org>
> >  Subject: Re: [HOT] Feedbacks about smartphones use for OSM field
> >         surveys
> >  Message-ID: <CBFAA879.6FB6%robert.banick at redcross.org>
> >  Content-Type: text/plain; charset="iso-8859-1"
> >
> >  Hi everyone,
> >
> >  I'm happy to see this discussion taking place, as I've been
> > personally researching and debating this question myself for a
> > little while now. It's my gut feeling that as software for data
> > collection improves smartphones will increasingly play a
> > complementary  role to traditional GPS devices in humanitarian fieldwork.
> >
> >  One contribution I might make: At the suggestion of the kind
> > people over at Catholic Relief Services, we're exploring linking
> > smartphones to high accuracy external GPS. The best model we've
> > encountered so far is the Dual XGPS 150<http://xgps150.dualav.com/>.
> > We had success with some preliminary trials in Lima last fall. When
> > the units connected with the smartphones we received very precise
> > coordinates, but we encountered hiccups maintaing the Bluetooth
> > connection with the cheapo Androids (the model name/number  escapes me)
> we were using.
> >
> >  Any thoughts, suggestions, or experiences others might have would be
> most appreciated.
> >
> >  Best,
> >  Robert
> >
> >
> >  Robert Banick | GIS Coordinator | International Services | American Red
> Cross
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
> >
> >
> >  --
> >
> > Charles Conley
> >
> > Chief Information Officer
> >
> >
> > 1400 16th Street, NW
> >  Suite 210
> >  Washington, DC 20036
> >
> > Tel:  +1 202-729-6795
> >  Skype: minemapper
> >  Web: www.immap.org
> >
> >
> >
>
>
> >
> >
> > _______________________________________________
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> >  HOT at openstreetmap.org
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> >
>
>
>
> >
> --
> Bye Bye,
>   Boris
>
>
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