[Taxacom] GPS units that record the time a waypoint was taken
sean.r.edwards at btinternet.com
Thu Mar 19 04:36:48 CDT 2009
Yes, you are right, my Canon at least requires a plug-in module (oddly, the
"Wireless File Transmitter WFT-E2"), which is not particularly cheap either,
but I think that other Canons incorporate the module into a battery pack (5D
MkII) etc., I'm not sure, and I guess it is only a matter of time before the
software is built in as you say it is with the Nikon.
By the way, I would stress that you can't just plug any GPS unit in -- it
must have the correct transfer protocol. I think that this is NMEA 0183 but
I guess that accuracy is that of the GPS unit, which with WAAS/EGNOS I find
takes me to within a few metres (1-3?) of a site revisited. Obviously it
depends on how many satellites it can see, and also how long you have not
moved from the site -- 10 minutes does seem to focus much more tightly from
an initial lock of maybe 5(+) metres away.
However, I also notice that the Canon record of the location is one decimal
point short of the unit's -- minutes with three points compared to the
units' four. I think that this means that conversions to e.g. the British
grid (which goes to the metre), may only go to a 10 metre accuracy?
I'm not sure how much of this is spurious precision rather than accuracy,
and I would appreciate comments, please?
I think I would never buy a camera with the GPS itself built in, but would
appreciate not having to buy an expensive module with features I don't want
to plug it into, and that makes the camera even bigger and more awkward.
That said, the system I use works like magic, and isn't really that bad a
blimp on the side since the camera is a tank anyway. The USB cable can be a
bit of a nuisance, but not much.
email: sean.r.edwards at btinternet.com
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