cdm/src/main/java/ucar/nc2/dataset/CoordinateSystem.java
public CoordinateAxis findAxis( AxisType type) {
    CoordinateAxis result = null;
    for (CoordinateAxis axis : coordAxes) {
      AxisType axisType = axis.getAxisType();
      if ((axisType != null) && (axisType == type))
        result = lesserRank(result, axis);
    }
    return result;
  }
public CoordinateAxis findAxis( AxisType type) {
    CoordinateAxis result = null;
    for (CoordinateAxis axis : coordAxes) {
      AxisType axisType = axis.getAxisType();
      if ((axisType != null) && (axisType == type))
        result = lesserRank(result, axis);
    }
    return result;
  }
Find the CoordinateAxis that has the given AxisType.
If more than one, return the one with lesser rank.
@param type look for this axisType
@return  CoordinateAxis of the given AxisType, else null.