private void checkExpectedEmpty() {
// can't check areal features
if (input.getDimension() >= 2) return;
// can't check positive distances
if (distance > 0.0) return;
// at this point can expect an empty result
if (!result.isEmpty()) {
isValid = false;
errorMsg = "Result is non-empty";
errorIndicator = result;
}
report("ExpectedEmpty");
}
