Reply by DS

Typical settings for offset and scale are at Zero and 45 degrees. But if the transducer’s linearity is 1 degree per 45, the reading at 22.5 degrees could be 21.5 to 23.5 degrees, even if 45 degrees is spot on.

While I am not familiar with the specs for the Wixey Guage, a device like that is designed for a single purpose and the transducer is typically 0.1 to 0.5 degrees per 45, depending on the manufacturer. Another factor in acuracy is called ‘repeatability’. Depending on the technology of the transducer, this can be 0.1 to 0.2 degrees over the entire range.

The transducer in a phone was probably envisioned to shuffle your playlist, flip your viewscreen, or play a video game and not so much for the purpose of precision measurements, so the linearity and repeatability requirements are probably much more lax than a more expensive, more precision, dedicated device.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251