Calculate QFE and/or QNH value from QNH and/or QFE, Altitude above sea level and Temperature (15°C is a standard temperature used in aviation).
Altitude can be automatically provided from external elevation API, like:
- https://open-elevation.com (can be slow)
- https://elevation-api.io (free version has very low accuraccy - 5km)
- https://open.mapquestapi.com (requires free API key)
Latitude and longitude needed for elevation API are provided from browser geolocalization (HTTPS needed for some browsers).
Mentioned above elevation API providers can be chosen in index.html, by commenting/uncommenting desired .get(), then() lines:
// api.open-elevation.com - can be slow, but free and accurate (~30m)
.get(`https://api.open-elevation.com/api/v1/lookup?locations=${input.lat},${input.lon}`)
.then(response => (app.altitude = response.data.results[0].elevation))
// elevation-api.io - fast, but free version has very low accuraccy (5km)
//.get(`https://elevation-api.io/api/elevation?points=${input.lat},${input.lon}`)
//.then(response => (app.altitude = response.data.elevations[0].elevation))
// open.mapquestapi.com - fast, free and accurate (~30m) - developr API key is needed (generate at https://developer.mapquest.com/)
//.get(`https://open.mapquestapi.com/elevation/v1/profile?key=YOUR_API_KEY_HERE&latLngCollection=${input.lat},${input.lon}`)
//.then(response => (app.altitude = response.data.elevationProfile[0].height))note: you need developer API key from MapQuest if you want to use MapQuest Elevation API. Change YOUR_API_KEY_HERE in index.html.
Based on work by Mathias Djärv - Calculate QFE value from QNH + Altitude (https://github.com/mdjarv/qfe)