galenstewart Posted January 31, 2004 Posted January 31, 2004 I cannot figure this out from the manual, so am hoping for help from other Garmin GPSMap 76S users ... How do I retrieve the gps satellite elevations for trackpoints and waypoints? By the default, the barometric elevations are downloaded. Is there a way to access the corresponding satellite elevations? Related to this, is there a way to force the unit to rely on satellite elevations (simply switching off the barometer results in NO elevations on the mapping page)? Thanks for any help that you might give me! Quote
peter Posted January 31, 2004 Posted January 31, 2004 Don't have a 76S, but AFAIK only the barometric altimeter readings are recorded in the tracklog data. You can check the GPS determined altitude at any time but I don't think the unit stores it in memory. If you set the 76S to automatically calibrate the altimeter based on the GPS readings then the two should be closely correlated. The barometric sensor helps to smooth out some of the short-term variation that's characteristic of GPS-based altitudes, while the time-averaged GPS readings are used to correct for longer-term variations of pressure due to changing weather conditions. The only case where I see a real need to record the GPS-based values directly is when in a pressurized plane where the barometer gets an artificial pressure reading. Quote
+Rubberhead Posted January 31, 2004 Posted January 31, 2004 I have an eTrex Vista with similar capabilities that has the same issues. There's no way that I know of to make the GPS use satellite altitude instead of the altimeter altitude. It's my understanding that the barometric altimeter was first added to the eTrex Summit to give vertical hikers an accurate elevation reading even if they didn't have a satellite lock. Like you, I wish I could choose which elevation was being displayed or recorded. You can get track point elevations by downloading the track into Mapsource. With the Vista I can also see a graphical elevation profile of a track but it doesn't give exact elevations for individual tracklog points. Hope this helps. Quote
+Rubberhead Posted January 31, 2004 Posted January 31, 2004 (edited) duplicate post - sorry but I'm using an iPAQ. Edited January 31, 2004 by Rubberhead Quote
+david&diana Posted January 31, 2004 Posted January 31, 2004 I cannot figure this out from the manual, so am hoping for help from other Garmin GPSMap 76S users ... How do I retrieve the gps satellite elevations for trackpoints and waypoints? By the default, the barometric elevations are downloaded. Is there a way to access the corresponding satellite elevations? Related to this, is there a way to force the unit to rely on satellite elevations (simply switching off the barometer results in NO elevations on the mapping page)? Thanks for any help that you might give me! You should be able to do this if you update the firmware in your GPSr. Garmin added the ability to virtually turn off the altimeter in version 3.40. Quote
+EraSeek Posted February 1, 2004 Posted February 1, 2004 I have a Map76. No barometric altimeter. Mine records the altitude from the sat fixes in my track logs and waypoints. Quote
galenstewart Posted February 1, 2004 Author Posted February 1, 2004 Well, I have the latest firmware (3.6), and while it does let me "simulate switching off" the barometric altimeter, I cannot get the satellite-based elevational measurements in its place. Even if it did, I would be faced with an either/or situation, instead of both, and, would also have to decide in advance of a hike whether I wanted the satellite or barometric elevations. I wonder if a (near-)future firmware upgrade would make it possible to get both the barometric + sat elevation measurements ... has anyone written to Garmin about this? Quote
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