stamp.direction error involving "units" objects

[monikashea]

When dir.mode = "CentroidAngle" in stamp.direction() there is an error:

Error in Ops.units(temp, 0) : 
  both operands of the expression should be "units" objects

I tested this with my own data as well as the package data and the same error occurs both times. The error does not occur when dir.mode = ConeModel, and I have not tested the other options.

Here is the code I used to test this using the package data:

data(fire1)
data(fire2)

stamp_test <- stamp(fire1, fire2, dc = 0, direction = FALSE, distance = TRUE)
dir_test <- stamp.direction(stamp_test, dir.mode = "CentroidAngle")
dir_test <- stamp.direction(stamp_test, dir.mode = "ConeModel")