Remember that you GPS signal is going to be affected by many things other
than the internal electronics. Things like over-story, cloud cover,
position of the satelites will all influence the data.  This is why when
people are doing stuff that requires solid datasets, they will place down
the GPS and let it record a series of points without moving it.  Then, you
put the points into the GIS and you are able to get an idea of the
precision.  It is also possible for you to geocorrect the coordinates.

I suggest that if you are seriously concerned about accuracy of less than a
meter that you use a model comparable to a Trimble XM or higher.  If your
accuracy can be within a hundred feet, its less serious.  I am not sure how
good garmins are these days, but all the GPS units are increasingly better
than only five years ago.

One option you could use is to take the GPS camera and take maybe a dozen
pictures of the exact same waypoint.  Do this at each of your study sites.
More pictures would be better.  Then, you take the coordinates for each
picture at each site, and average them.  This will give you a mean with SD
or SE.  This way, you will know the actual accuracy and precision of the
unit under the weather conditions at the site where you were collecting
data.  You can also check this against a better GPS unit if desiered.  By
doing this at one point, then moving about your site, you will know the
error and can report some kind of confidence in regard to the location of
each point where vegetation is photographed.  It will probably have pretty
consistent precision on any given day within a specific site.  This is a
fair assumption, but some testing at home or on campus should be conducted
to verify it.

one thing to also remember is that what is reported in the paperwork is
best case scenario.  The model will almost never reach this
precision/accuracy in teh field.  The high-dollar GPS units will be more
consistently close than the cheap "toy" models.

How important your accuracy and precision are in thsi study shoud be
critical in deciding whether to go with one of these models or going with a
genuine research grade unit. A geoexploer XM or higher is a few thousand
dollars last Iooked.

On Sun, May 3, 2015 at 1:52 PM, Jacob Hadle <> wrote:

> Hello,
> I have a question for those of you who are familiar with point and shoot
> digital cameras that have built-in GPS units. A project I have acquired
> this summer involves a plant inventory on a ~7,000 acres site (open and
> dense canopy areas). In part, the protocol requires us to take a picture
> of each plant species and document their latitude and longitude
> coordinates. To optimizes my time effectively, using a camera that
> geotags each picture would seem to work well.
> The main interests I have in the point and shoot camera in not so much
> how the quality the picture takes, but how accurate the camera will pick
> up coordinates. I have spent a considerable amount of time online, and
> calling local camera stores researching which point and shoot camera
> would have the best GPS quality; however, I have found very little
> information about the accuracy and performance in these built-in GPS
> units. I am currently looking into the Canon PowerShot D20 or the Ricoh
> G700 SE-M.
> If anyone has experience using digital cameras with built-in GPS units
> in the field, I would truly appreciate your thoughts.
> Most grateful,
> Jacob

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