Path: csiph.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: rbowman Newsgroups: comp.os.linux.misc Subject: Re: The "Standards" Game Date: 4 Dec 2025 02:58:44 GMT Lines: 43 Message-ID: References: <106mke5$1di32$1@dont-email.me> <10g7bqf$j278$2@dont-email.me> <10gd4jq$2ptu7$4@dont-email.me> <10gejtd$39ian$2@dont-email.me> <10ghsi9$gnag$1@dont-email.me> <5qm50mx65q.ln2@Telcontar.valinor> <7ud60mx8d8.ln2@Telcontar.valinor> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Trace: individual.net uB1tp4X6KlW/r9qDfa7/vg998YyZXTahUxMKEWVL8nIK4pxEJz Cancel-Lock: sha1:c1JibuEFfLaCZLwt/sk5vOaHu4I= sha256:dGDO86TRnzjIUpESYeMEl4zERXIrrOTsiMdvDVttDXg= User-Agent: Pan/0.162 (Pokrosvk) Xref: csiph.com comp.os.linux.misc:78262 On Wed, 3 Dec 2025 19:59:51 +0100, Carlos E.R. wrote: > Looking at the fitbit app, I did two hikes on Sunday at the same time > and of the same duration. None tell the height difference, but I know > there is some. Turns out that the second one is an automated import from > the app "Strava". I don't know if you can do it with Fitbit but with the Zepp app I can dump the track data in a gpx file. (GPS Exchange). The track is a set of track points 1122.58 0.0 0.0 70 The GPS elevation is the first thing to degrade if the satellite constellation is marginal but it's there. I think they don't use it since it might give false readings. The Zepp app has a slider 'Altitude Calibration' which is usually turned off. I've seen it turned on occasionally. Getting from barometric pressure to altitude is sort of a hack so I believe if they look at a point in a geodatabase and the barometer calculation is too far off they fall back on the GPS. However their algorithm is faulty and it often reports almost double the actual gain. I wrote a program to parse the gpx files and handle the successive points that comes out with the actual gain. I also have another program to convert gpx to GeoJSON so I can display the track on a OSM basemap. No digital map is without errors and I like to get a second opinion. Ob Linux: of course I do the conversions with a C program compiled with gcc and display the webmap using node.js on a Linux box.