Top Altimeter: GPS Elevation

Top Altimeter is a GPS elevation tracker and altimeter that fuses GPS, barometer and EGM96 into one stable, precise altitude reading, auto-logs every climb with elevation curves, and works fully offline with GPX/CSV export.

🌍 **Four elevation sources**
- EGM96 geoid-corrected altitude (recommended, most stable)
- System MSL altitude (Android 14+)
- NMEA GGA altitude
- WGS84 ellipsoid raw height

Every fix runs a health check: we watch for stationary drift, spikes, out-of-range values and accuracy, then recommend the steadiest source.

🌡️ **Barometer fusion**
On devices with a barometric sensor, pressure data is fused with GNSS/GPS for smoother readings; when no sensor is present it falls back to pure GNSS.

📝 **Auto logging**
Record by time interval or by elevation-change threshold, with background persistence so logging continues even when the screen is off. Browse the list entry by entry, and the chart shows total ascent, peak, duration and data-point count.
You can also check in manually to capture your current altitude and GPS coordinates on the spot.

📷 **Altimeter camera**
Snap a photo with an altitude watermark — elevation, unit and GPS coordinates are stamped right onto the image, ready to share.

📷 **Photos, video & notes**
Attach a photo or video of the scene and add a text note to any elevation entry — remember not just the number, but the moment.

🛰️ **Satellites**
GPS, GLONASS, Galileo, BeiDou & QZSS — See which constellations are in use and the C/N0 signal strength of every visible satellite.

📤 **Export**
Export any time range as GPX (Google Earth, Strava, Garmin) or CSV. Your data stays on the device — no account, no server, no tracking. Works offline, no internet required.

🎨 **Your badge, your style**
Choose a classic aviation dial or a modern look, adjust shape and size, pick light/dark themes, and switch between meters and feet.

🔒 **Permissions**
- Display over other apps — to show the floating altitude badge above other apps.
- Location (including background): keep altitude updated and keep recording while the screen is off.

⚠️ **Note:** this app is not a survey-grade instrument; readings are for reference only.

Recent changes:
a. Support for taking photos with a watermark, embedding altitude, latitude/longitude, and date information into the photo.
b. Enhanced altitude log analysis, supporting: automatic trip segmentation with statistics including total ascent, total descent, trip duration, net elevation change, average grade, horizontal distance, and maximum ascent rate.