I am currently performing some geographical coordinate calculations that use radians as their base units. In trying to leverage the distance command found in the Mapping Toolbox there seem to be some odd results when trying to utilize the 'radians' units option.
As an example, consider the fairly straightforward scenario.
[arclen, az] = distance(0,0,0,90);
The results for both 'arclen' and 'az' are 90 as would be expected. However if units are adjusted to 'radians' only the 'az' result appears appropriate.
[arclen, az] = distance(0,0,0,90,'radians');
The outcome for 'az' is the expected 1.5708. I was expecting 'arclen' to also show an answer of 1.5708, but instead the outcome 2.0354.
If a conversion from the default units output is applied to the 'arclen' and 'az' after the 'distance' calculation by employing 'deg2rad', both results are the expected 1.5708.
Am I misunderstanding something or is this indeed an error in conversion in the base 'distance' command when 'radians' is used for units?