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D2X GPS location inaccuracy

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Anonymous
April 9, 2005 5:34:02 AM

Archived from groups: rec.photo.digital (More info?)

One problem I've found with the GPS (MC-35) functionality for the Nikon
D2X is that it doesn't record enough significant digits for the seconds
(location wise).

For example, most GPS receivers will record a location like:

N 42 51.867
W 85 38.834

But the D2X only stores (truncating the last digit):

N 42 51.86
W 85 38.83

EXIF (in Nikon View) will show seconds rather that decimal minutes:

N 42 51' 51.6"
W 85 38' 49.8"

Ideally it should store/show one more digit like:

N 42 51' 52.02"
W 85 38' 50.04"

Note that its actually recording 51.6 rather than even 52.0(2) which is
more accurate and actually a big difference.

I know this seems minor but it means the D2X only records locations to
an accuracy of about 60 feet rather than about 10 feet like most GPS
receivers are capable of (under ideal conditions). Unfortunately, this
is detrimental to the purpose for which I was hoping to use the D2X.

I've called Nikon and asked them to make a firmware change, but unless
the issue gets some visibility I doubt it will. They said if they got
enough complaints that they might consider a fix. Nikon support can be
reached at 1-800-645-6689, Option 1-1-2-2. Please give them a call.

You can also email them using the form at:
<http://support.nikontech.com/cgi-bin/nikonusa.cfg/php/e...;

For more information read:
<http://forums.dpreview.com/forums/read.asp?forum=1021&m...;

Thanks,
-Joel
Anonymous
April 9, 2005 6:25:31 AM

Archived from groups: rec.photo.digital (More info?)

Joel Bierling wrote:
> One problem I've found with the GPS (MC-35) functionality for the Nikon
> D2X is that it doesn't record enough significant digits for the seconds
> (location wise).
>
> For example, most GPS receivers will record a location like:
>
> N 42 51.867
> W 85 38.834
>
> But the D2X only stores (truncating the last digit):
>
> N 42 51.86
> W 85 38.83
>
> EXIF (in Nikon View) will show seconds rather that decimal minutes:
>
> N 42 51' 51.6"
> W 85 38' 49.8"
>
> Ideally it should store/show one more digit like:
>
> N 42 51' 52.02"
> W 85 38' 50.04"
>
> Note that its actually recording 51.6 rather than even 52.0(2) which is
> more accurate and actually a big difference.
>
> I know this seems minor but it means the D2X only records locations to
> an accuracy of about 60 feet rather than about 10 feet like most GPS
> receivers are capable of (under ideal conditions). Unfortunately, this
> is detrimental to the purpose for which I was hoping to use the D2X.
>
> I've called Nikon and asked them to make a firmware change, but unless
> the issue gets some visibility I doubt it will. They said if they got
> enough complaints that they might consider a fix. Nikon support can be
> reached at 1-800-645-6689, Option 1-1-2-2. Please give them a call.
>
> You can also email them using the form at:
> <http://support.nikontech.com/cgi-bin/nikonusa.cfg/php/e...;
>
>
> For more information read:
> <http://forums.dpreview.com/forums/read.asp?forum=1021&m...;
>
> Thanks,
> -Joel

Accuracy of GPS data is normally given as 50 feet (+ or -). So giving
that extra digit may mislead. Even though my GPS will not 'go to zero'
until I drive UNDER the carport when I get 'home', the indicated value
doesn't actually change until I get to that point (assuming I have 4 or
more satellites acquired). That last digit is within the zone of
uncertainty, and may not be of real value. That's probably why they
didn't include it. Why do you need that kind of accuracy?


--
Ron Hunter rphunter@charter.net
Anonymous
April 9, 2005 12:42:25 PM

Archived from groups: rec.photo.digital (More info?)

Joel Bierling <email1@bierling.net> wrote:

: I know this seems minor but it means the D2X only records locations to
: an accuracy of about 60 feet rather than about 10 feet like most GPS
: receivers are capable of (under ideal conditions). Unfortunately, this
: is detrimental to the purpose for which I was hoping to use the D2X.

It may be that to get that much more accuracy the GPS antenna would have
to be physically bigger and or the electronics to decode that much more
accurately (such as differential arrays) would be prohibitively large for
the application. Most people using this function would likley be
comfortable with the 60' resolution. Most people are probably not using a
prosumer camera as a surveyor transit, and thus don't have a need for more
than a 60' resolution. If a more precise location is required, a seperate
GPS receiver would be better. Now if you need that more exacting data
stored with the photo info, you might ask if there is a way to interface
a seperate GPS with the camera. It might be possible for such an
interface to be designed to use the USB port for data collection.
This would only require a software update of the camera and an interface
box to connect the two items. If such a device were available, then you
could even use a very high quality external GPS that could possibly read
down to +- 3 feet.

Randy

==========
Randy Berbaum
Champaign, IL
Related resources
Anonymous
April 9, 2005 2:11:11 PM

Archived from groups: rec.photo.digital (More info?)

Ron Hunter wrote:
> Accuracy of GPS data is normally given as 50 feet (+ or -). So giving
> that extra digit may mislead. Even though my GPS will not 'go to zero'
> until I drive UNDER the carport when I get 'home', the indicated value
> doesn't actually change until I get to that point (assuming I have 4 or
> more satellites acquired).

Actually, both Magellan and Garmin advertise their WAAS capable units as
being accurate to within 3m or 10ft 95% of the time (under ideal
conditions of course).

> That last digit is within the zone of
> uncertainty, and may not be of real value. That's probably why they
> didn't include it.

I will grant you the last digit does contain a degree of uncertainty at
least in terms of its absolute value when compared to a known stationary
position. However, in terms of two recorded positions taken by the same
receiever close together in time the relative positions indicated by the
last digit are significant.

> Why do you need that kind of accuracy?

Virtual tours. I've explained it in a little more detail on the
dpreview thread.

Thanks,
-Joel
Anonymous
April 9, 2005 2:18:54 PM

Archived from groups: rec.photo.digital (More info?)

Randy Berbaum wrote:
> the application. Most people using this function would likley be
> comfortable with the 60' resolution.

Maybe, but both Magellan and Garmin advertise their WAAS capable units
as being accurate to within 3m or 10ft 95% of the time (under ideal
conditions of course) so Nikon is discarding data.

> Most people are probably not using a
> prosumer camera as a surveyor transit,

Just a nitpick, but the Nikon D2X is not a prosumer camera.

> and thus don't have a need for more
> than a 60' resolution. If a more precise location is required, a seperate
> GPS receiver would be better.

The Nikon D2X does not have an internal GPS receiver. It already
connects to an external one, but does not record the full position
provided to it by the external device. That is the problem.

> Now if you need that more exacting data
> stored with the photo info, you might ask if there is a way to interface
> a seperate GPS with the camera.

This is already what we're talking about.

> This would only require a software update of the camera and an interface
> box to connect the two items. If such a device were available, then you
> could even use a very high quality external GPS that could possibly read
> down to +- 3 feet.

Yes, I'm hoping Nikon provides a software (firmware) update to fix the
problem.

Thanks,
-Joel
Anonymous
April 9, 2005 7:44:56 PM

Archived from groups: rec.photo.digital (More info?)

Have you tried setting the GPS to show degrees, minutes and seconds rather
than just degrees and minutes? It may then transfer info properly.. Don't
know, but worth a try.


"Joel Bierling" <email1@bierling.net> wrote in message
news:D 37pb7$9v8$1@newsreader.mailgate.org...
> One problem I've found with the GPS (MC-35) functionality for the Nikon
> D2X is that it doesn't record enough significant digits for the seconds
> (location wise).
>
> For example, most GPS receivers will record a location like:
>
> N 42 51.867
> W 85 38.834
>
> But the D2X only stores (truncating the last digit):
>
> N 42 51.86
> W 85 38.83
>
> EXIF (in Nikon View) will show seconds rather that decimal minutes:
>
> N 42 51' 51.6"
> W 85 38' 49.8"
>
> Ideally it should store/show one more digit like:
>
> N 42 51' 52.02"
> W 85 38' 50.04"
>
> Note that its actually recording 51.6 rather than even 52.0(2) which is
> more accurate and actually a big difference.
>
> I know this seems minor but it means the D2X only records locations to
> an accuracy of about 60 feet rather than about 10 feet like most GPS
> receivers are capable of (under ideal conditions). Unfortunately, this
> is detrimental to the purpose for which I was hoping to use the D2X.
>
> I've called Nikon and asked them to make a firmware change, but unless
> the issue gets some visibility I doubt it will. They said if they got
> enough complaints that they might consider a fix. Nikon support can be
> reached at 1-800-645-6689, Option 1-1-2-2. Please give them a call.
>
> You can also email them using the form at:
>
<http://support.nikontech.com/cgi-bin/nikonusa.cfg/php/e...
=TYS9DuCh&p_lva=238&p_sp=&p_li=>
>
> For more information read:
> <http://forums.dpreview.com/forums/read.asp?forum=1021&m...;
>
> Thanks,
> -Joel
Anonymous
April 9, 2005 7:44:57 PM

Archived from groups: rec.photo.digital (More info?)

Brian Mitchell wrote:
> Have you tried setting the GPS to show degrees, minutes and seconds rather
> than just degrees and minutes? It may then transfer info properly.. Don't
> know, but worth a try.

The quick answer is no, I have not tried changing the GPS format, but
the D2X reads the NMEA data stream connected to the device which should
not be affected by display settings.

-Joel
Anonymous
April 10, 2005 12:01:38 AM

Archived from groups: rec.photo.digital (More info?)

Joel Bierling wrote:
> Ron Hunter wrote:
>
>> Accuracy of GPS data is normally given as 50 feet (+ or -). So giving
>> that extra digit may mislead. Even though my GPS will not 'go to
>> zero' until I drive UNDER the carport when I get 'home', the indicated
>> value doesn't actually change until I get to that point (assuming I
>> have 4 or more satellites acquired).
>
>
> Actually, both Magellan and Garmin advertise their WAAS capable units as
> being accurate to within 3m or 10ft 95% of the time (under ideal
> conditions of course).
>
> > That last digit is within the zone of
> > uncertainty, and may not be of real value. That's probably why they
> > didn't include it.
>
> I will grant you the last digit does contain a degree of uncertainty at
> least in terms of its absolute value when compared to a known stationary
> position. However, in terms of two recorded positions taken by the same
> receiever close together in time the relative positions indicated by the
> last digit are significant.
>
>> Why do you need that kind of accuracy?
>
>
> Virtual tours. I've explained it in a little more detail on the
> dpreview thread.
>
> Thanks,
> -Joel
Not all GPS receivers are WAAS capable, and even when they are, the WAAS
transmissions aren't exactly full coverage.


--
Ron Hunter rphunter@charter.net
Anonymous
April 10, 2005 7:55:36 AM

Archived from groups: rec.photo.digital (More info?)

Joel Bierling <email1@bierling.net> wrote:

: The Nikon D2X does not have an internal GPS receiver. It already
: connects to an external one, but does not record the full position
: provided to it by the external device. That is the problem.

Ok, I was misunderstanding your problem. Not knowing the camera (and
knowing how some camera manufacturers will put almost anything into their
camera to be able to crow about an exclusive "feature") I ass-umed an
incorrect assumption. So it is just a case that the camera is not
recording the full externally acquired number with the photo.

I stand corrected. In the words of Emily Latella...Never mind. :) 

Randy

==========
Randy Berbaum
Champaign, IL
Anonymous
April 10, 2005 10:55:01 AM

Archived from groups: rec.photo.digital (More info?)

Ron Hunter <rphunter@charter.net> writes:

>Not all GPS receivers are WAAS capable, and even when they are, the WAAS
>transmissions aren't exactly full coverage.

Most GPS receivers *are* capable of accepting differential correction
data in RTCM format. If you're within reception range of one of the
Coast Guard DGPS beacons, and you have a suitable DGPS receiver
connected to your GPS receiver, accuracy is 1 or 2 m.

Some amateur radio APRS systems, used for position tracking, broadcast
differential correction data from base to mobiles. Precision farming
GPS systems, and even GPS-carrying golf carts, get DGPS corrections via
radio link.

Even completely uncorrected GPS positions are accurate to about 7 m
these days, given decent sky coverage and a modern receiver.

So GPS positions with this sort of accuracy are not rare, and it seems
silly for the camera to truncate whatever data it is given. It should
just record the position to however many decimal points the GPS receiver
provides.

Dave
!