Guest Olar Posted September 2, 2001 Share Posted September 2, 2001 I've been doing some hiking lately on a trail system where the main trail distances are marked on the map but not the side trails. I've been using my GPSR to keep track of trip distance but I am getting readings much less than what they should be. Today for instance my trip was approx. 10 kilometers but my 315 reads 5.8 Km. I downloaded waypoints and track from the 315 to ExpertGPS and it shows a distance of 9.6 Km track distance. Can anyone explain why the discrepancy? Thanks, Olar Quote Link to comment
Guest JasonW Posted September 3, 2001 Share Posted September 3, 2001 Was your trip in a forest ? I know from my trips through tunnels and the like that the Mag 315 doesn't register distance when the satellite constellation is not visible (or indeed when the unit is off) Quote Link to comment
Guest DaveA Posted September 3, 2001 Share Posted September 3, 2001 10 kilometers is roughly 6 miles. Are you certain that your unit isn't measuring miles rather than kilometers? I know that sounds unlikely, but I didn't want to avoid mentioning the obvious. I know others (including me) with 315s that have used them to measure distances and they have been right on. Not applicable to this situation, but GPSRs only measure horizontal distance so if you move 1 mile with many up and downward slopes your measured distance will be less than a mile. Quote Link to comment
Guest Kerry Posted September 3, 2001 Share Posted September 3, 2001 The distance configuration (km v Mi) is worth looking at. Also what sort of time frame for the 10km? Any chance the 315 was spending some of it's time "thinking" you were stationary (walking less than the speed where auto averaging kicks in) and in averaging mode? Cheers, Kerry. [This message has been edited by Kerry (edited 03 September 2001).] Quote Link to comment
Guest Olar Posted September 3, 2001 Share Posted September 3, 2001 "Was your trip in a forest ?" "......so if you move 1 mile with many up and downward slopes your measured distance will be less than a mile." "Also what sort of time frame for the 10km?" Yes the route was 90% under heavy tree cover and through numerous valleys/gulleys with a lot of slow climbing of slopes and switchbacks. Took 3 hours total. I guess what I'm looking at is a combination of occasional poor sat locks, unit averaging due to slow speed and a lot of vertical ups and downs. Thank you all for your help! ------------------ Happy Caching, Olar "if you come to a fork in the trail, then take it!" [This message has been edited by Olar (edited 03 September 2001).] Quote Link to comment
Guest Gliderguy Posted September 3, 2001 Share Posted September 3, 2001 I wonder if the unit is only counting startpoint to endpoint distance? Quote Link to comment
Guest JasonW Posted September 3, 2001 Share Posted September 3, 2001 Mine doesn't - at least not under normal (ie. sky visible) circumstances - it counts the actual distance travelled on the ground - or a close approximation to it (depending on the sample intervals I'd guess) [This message has been edited by JasonW (edited 03 September 2001).] Quote Link to comment
Guest AZMark Posted September 3, 2001 Share Posted September 3, 2001 Maggie auto averaging raises it's ugly head again. Quote Link to comment
Guest Vagabond Posted September 10, 2001 Share Posted September 10, 2001 Gee guys my old Lowrance Global Nav 212 shows distance traveled in mode 2 of navigation. Quote Link to comment
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