filter method
@see org.locationtech.jts.geom.CoordinateSequenceFilter#isGeometryChanged */
Implementation
void filter(CoordinateSequence seq, int i) {
if (checkOrdinateFlags.contains(Ordinate.Z) &&
!outputOrdinates.contains(Ordinate.Z)) {
if (!seq.getZ(i).isNaN) outputOrdinates.add(Ordinate.Z);
}
if (checkOrdinateFlags.contains(Ordinate.M) &&
!outputOrdinates.contains(Ordinate.M)) {
if (!seq.getM(i).isNaN) outputOrdinates.add(Ordinate.M);
}
}