gml:rangeMeaning describes the meaning of axis value range specified bygml:minimumValue and gml:maximumValue. This element shall be omitted when bothgml:minimumValue and gml:maximumValue are omitted. This element should be included whengml:minimumValue and/or gml:maximumValue are included. If this element is omitted when thegml:minimumValue and/or gml:maximumValue are included, the meaning is unspecified. ThecodeSpace attribute shall reference a source of information specifying the values andmeanings of all the allowed string values for this property.