BTW, I mislaid my O-GPS1 manual a couple of months ago and needed to do a web search to find a copy (since Pentax does not offer a pdf download). One of the pages that showed up in my searches was: http://www.gyes.eu/photo/photostart.htm which may well have been referenced here before. 'Tis a review/discussion of the unit plus links to some other resources including a discussion of astrotracer accuracy. FWIW.
stan On Sep 14, 2013, at 2:57 AM, David Mann wrote: > On Sep 14, 2013, at 2:13 AM, Darren Addy <[email protected]> wrote: > >> Elevation of location. (ASIDE: This seems to be where "all GPS units >> exhibit a weakness" but I'm not sure why that is. According to this >> PDF, >> http://www.nasa.gov/centers/johnson/pdf/584738main_Wings-ch5c-pgs360-369.pdf >> the space shuttle created topographical data sets that can give the >> elevation for virtually any location. Perhaps it is just not built >> into the GPS system yet, or there is no method for the GPS to "look it >> up" and enter it into the calculations.) > > FWIW I think Garmin Connect uses that database. There's an "elevation > correction" option that you can activate. It's not much good when you're out > and about though as this is only done after you've come back and uploaded > your route :) > > What Matthew said about the difference in accuracy is the same as what I'd > heard so I've deleted my version of the same explanation. > > My Garmin watch uses a barometric altimeter which auto-calibrates whenever > I'm near a known location (ie somewhere I've programmed into the watch with > its elevation). If the altimeter goes wonky it will switch to GPS elevation, > but the manual doesn't say the exact conditions under which this happens. > Being barometric it is of course susceptible to changes in weather conditions > but once it's calibrated it's pretty good: good enough to give me a fairly > accurate gradient reading on the hills. > > Cheers, > Dave > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
