rakeck

In comparing numbers found on many recent printed maps and Wiki, and actual signs at the CO summits, I'm finding there is a discrepancy of more than 20 feet one way or the other on about 60% of them. I've actually seen what has got to be actual sign creation 'typos on some because there are 300 foot and 900 discrepancies on some when compared to Wiki and and Goggle Earth. Anyway, I just find it interesting for now as I'm building a pass rating system and guide for truckers

I wonder how much discrepancy there is from the 1929 datum, the 1988 datum and what today's datum may be?

Doing a lot of travel throughout Colorado last few weeks and I began thinking about something ... the mountain passes were posted with their elevations many, many decades ago, long before satellites and GPS technology. I somewhat understand the methods engineers might have used at that time to determine a pass's elevation but honestly, how much accuracy can be in these numbers? As an aside, it blows my mind how accurate they in fact were given what they had to work with. Example, If you look at Loveland Pass, CO. The sign at the tops says 11,990, Google Earth says 12,008, MY WAAS Garmin 62s with a roof mounted GPS puck and altimeter not used for altitude correction said 12,019. I'm just asking questions to see if any here may have any relevant knowledge on the subject or opinions they may care to share. If satellite technology were to see where corrections may be called for, I wonder if states would undo a half-century worth of history and replace the data and the signs for say 40 feet of "error". Does it make a difference to anybody? Furthermore, I suppose it could be said that sea level is relative to what over centuries?

I guess I'll do it this way it works but is slow. Using GPSVisualizer ... With utility, convert my .gpx to .txt file on my desktop open the .txt file with Excel, make necessary elevation edits, remove temp column data, re-save (keeping .txt format) Convert the .txt file to a .gpx file with utility Save .gpx file from web into a different folder on my PC Done

This is what i get with my garmin. The profile is fine, and I understand there may some 'errors' but overall the device logs beautifully smooth and I'm OK with the results but the sign at the top of trout Creek says 9,487 feet. I use WAAS and I've learned that the altimeter needs to be bypassed when operating at significantly fast elevation changes (above 4.5%/60 MPH) or the results will be wildy off. I'd still like to modify all the points to get me to an image that reflects 9487. On balance the elevation rise is more or less accurate and the dips and such are more or less accurate. I'm not trying to go to the mars with this project, i simply want to edit my recorded data, put it into a profiler, and get an end result that matches with the real world summit sign. I've messed around with TrackProfiler but it doesn't want to display anything in feet/miles even though I've modified the option setting, and when I attempt a global elevation change, it doesn't seem to do anything.

I hear you grasscatcher, but I'm just interested in getting a profile image and associated text to "equal" what the world associates with a given pass ... the sign at the top. Yes, I'm finding a lot of published pass elevations don't match with current technology findings, but if a sign at the top says 10,000 feet, then the elevation profile peak should say 10,0000 just so as not to confuse people. the altimeter on a modern GPS is still more accurate (and without the wild erroneous ground peaks and valleys) in a 15 minute time span than any google earth elevation profile you can create in mountainous areas with only low res imagery

I thought this would be a simple web search that would yield a number of paid and free apps, but .. If I have a .gpx file from a Garmin device that contains elevation data (altimeter), and I'm looking to replicate real-world documented data as closely as possible, and I've determined that one "benchmark point" (summit) in the path file is 20 feet too high, how can I programatically modify all the elevation points in the gpx file to be the original elevation value, minus 20 feet? I don't mind paying a reasonable amount for an app that works well. Thanks

The relative feedback of the altimeter is all I'm looking for. I can later determine if a global modification of the log file altitude data is in order as I can compare the logged max elevation to the documented peak elevation, and if there is a 50 foot difference, I can add or subtract 50 foot across the entire log. I will try turning the track log feature on/off in the menu as a means of pausing and resuming the feature on demand. And will look into the stopwatch feature as a possible solution. Thanks

I was wondering if there is a way to effectively "pause" the point logging feature on the 62S? I need to log 2-4 second intervals (plotting mountain grades). I also need to rely on the altimeter accuracy, so I prefer to not turn off the unit once it is calibrated. Sometimes it is not convenient or safe to stop and save the points log to a track at the end of the course, and it is sort of time consuming to clear the accumulated erroneous data to resume with logging wanted data. And I don't want it logging a bunch of erroneous data that will have to be stripped out later if I don't stop it in a timely manner via a saving of the track process. A pause and resume logging feature would be nice if anyone from Garmin checks in here. Thanks in advance