Scientific Altimeter

SCIENTIFIC ALTIMETER Nationwide One-Touch Calibration The only iOS altimeter with nationwide one-touch calibration using USGS ground-truth elevation data. Tap once, get instant calibration anywhere in the United States. No manual entry, no guesswork. Designed for field researchers, GIS professionals, educators, and students. KEY FEATURES - NATIONWIDE ONE-TOUCH CALIBRATION Automatic USGS 3DEP calibration anywhere in the US with cellular or WiFi - DUAL SENSOR COMPARISON Record GPS altitude and calibrated barometric altitude with accuracy estimates - MANUAL CALIBRATION Enter known elevations for offline fieldwork or international use - SMART RECALIBRATION Time and pressure-change monitoring maintains accuracy during long field sessions - PROFESSIONAL EXPORTS CSV, GPX, KML, and GeoJSON formats ready for GIS analysis - WORKS OFFLINE GPS-only mode and manual calibration support remote fieldwork WHY ONE-TOUCH CALIBRATION MATTERS Other altimeter apps require manual elevation lookup from maps or uncalibrated pressure readings. Scientific Altimeter automatically queries USGS elevation at your GPS coordinates and calibrates your barometer to ground truth. One tap, instant accuracy. SCIENTIFIC APPROACH Barometers measure pressure changes precisely but need calibration. Weather systems cause drift. Scientific Altimeter uses USGS 3DEP data for ground-truth reference and monitors pressure changes to suggest recalibration when needed. Full metadata in exports enables reproducible fieldwork and quality assessment. IDEAL FOR - Watershed and terrain surveys - Environmental monitoring - GIS ground-truthing - Educational field exercises - Ecological transects - GPS accuracy verification DATA QUALITY Each point includes timestamp, coordinates, GPS altitude, barometric altitude, and accuracy estimates. Compare GPS (stable long-term) with barometer (smooth short-term) for optimal results. PRIVACY - All data stored locally - No registration required - No tracking or ads - Location used only for GPS and USGS queries - Open methodology REQUIREMENTS iPhone 6 or newer, iOS 17.0+, location permission, internet for USGS calibration Created by a GIS specialist for the research community. Free forever. The only altimeter with true nationwide one-touch calibration.