For improved accuracy, XFM allows a feature to have its symbology determined by the value of properties stored in the feature. In legacy projects, modeling a 200 mm pipe in red and a 300 mm pipe in green required separate features. In XFM, the color of a feature can be based on its properties. For example, if a Road feature has a property named Type with a value of 2-Lane, the color is 3. If Type is 4-Lane, the color value is 5. And if Type is another value, then the color value is 1 which is the default. A common practice for symbology is to set the default value with no criteria as the last defined entry.

OpenCities Geospatial Administrator allows commonly used criteria to be assigned a name and stored in the XML metadata. When specifying criteria, the name may be used in place of the actual expression. Using named criteria ensures the feature's property type is checked. Any criteria defined in a property based symbology (PBS) rule should be limited to feature-based criteria since operation properties are not guaranteed to exist when the PBS rule is evaluated.

If the criteria is only used for a single feature, the feature_instance_alias part of the property name can be excluded. For example, if the Road feature's named criteria is road_2lane, it is defined as COMPARE("[Road:Type]","2-Lane",). If the criteria is only used for the Road feature, it could also be defined as COMPARE("[Type]","2-Lane",). See "Criteria" for more information.