altimeter

Have had several over the years and enjoy playing with them driving, hiking, and flying. Phones are replacing them but still a great overland tool and toy. There are some great options lately from simple altimeters, to ABC (altimeter, barometer, compass) watches, to smart watches. 1. Casio...

Howdy Can anyone recommend a pretty accurate cell phone app altimeter ? I have a long gravity flow domestic water line and I need to do some regrading.....need elevation data along about 1/2 mile of pipeline. Many thanks David Graves