We present a method to add confidence limits to level curves, drawn on a map of a Gaussian random surface, measured with or without error on a regular or irregular grid. The method is based on the conditional level crossing intensity measure for non-stationary Gaussian fields.
"How reliable are contour curves? Confidence sets for level contours." Bernoulli 1 (4) 301 - 319, December 1995. https://doi.org/10.3150/bj/1193758708