This functions assigns a const attribute set to "time" to a numeric vector.
TimeConstant(x)The input vector with an additional attribute const set to "time".
(numeric vector) covariate values for each location. Values are used for each time-point.
A time-constant covariate has the form $$\mathbf{x}_t = \mathbf{x},$$ for some fixed vector \(\mathbf{x} = (x_1, \ldots, x_p)',\) i.e., it has the same value for all time-points \(t\), where \(x_i\) is the value of the covariate at location \(i\).
SpatialConstant