Untitled attachment

Notices where this attachment appears

1. Embed this notice
   Brion Vibber :blobcatcoffee:​ (brion@bikeshed.vibber.net)'s status on Monday, 09-Jan-2023 16:19:43 JST Brion Vibber :blobcatcoffee:​

   People think of GPS as giving lat/lon coords, but it actually calculates X/Y/Z relative to the center of the Earth, then converts them according to the WGS84 datum[1] into lat/lon and altitude.

   However in aviation, the primary altitude measure for navigation remains the classic barometric pressure-based altimeter.

   At lower altitudes, you calibrate the instrument relative to readings from a local airfield; at higher altitudes everyone uses a standard calibration.

   [1] https://en.wikipedia.org/wiki/World_Geodetic_System