dynamicFeature.xsd See ISO/DIS 19136 15.6. A number of types and relationships are defined to represent the time-varying properties of geographic features. In a comprehensive treatment of spatiotemporal modeling, Langran (see Bibliography) distinguished three principal temporal entities: states, events, and evidence; the schema specified in the following Subclauses incorporates elements for each. GML is an OGC Standard. Copyright (c) 2007,2010 Open Geospatial Consortium, Inc. All Rights Reserved. To obtain additional rights of use, visit http://www.opengeospatial.org/legal/ . Evidence is represented by a simple gml:dataSource or gml:dataSourceReference property that indicates the source of the temporal data. The remote link attributes of the gml:dataSource element have been deprecated along with its current type. Evidence is represented by a simple gml:dataSource or gml:dataSourceReference property that indicates the source of the temporal data. A convenience group. This allows an application schema developer to include dynamic properties in a content model in a standard fashion. States are captured by time-stamped instances of a feature. The content model extends the standard gml:AbstractFeatureType with the gml:dynamicProperties model group. Each time-stamped instance represents a 'snapshot' of a feature. The dynamic feature classes will normally be extended to suit particular applications. A dynamic feature bears either a time stamp or a history. A gml:DynamicFeatureCollection is a feature collection that has a gml:validTime property (i.e. is a snapshot of the feature collection) or which has a gml:history property that contains one or more gml:AbstractTimeSlices each of which contain values of the time varying properties of the feature collection. Note that the gml:DynamicFeatureCollection may be one of the following: 1. A feature collection which consists of static feature members (members do not change in time) but which has properties of the collection object as a whole that do change in time . 2. A feature collection which consists of dynamic feature members (the members are gml:DynamicFeatures) but which also has properties of the collection as a whole that vary in time. To describe an event — an action that occurs at an instant or over an interval of time — GML provides the gml:AbtractTimeSlice element. A timeslice encapsulates the time-varying properties of a dynamic feature -- it shall be extended to represent a time stamped projection of a specific feature. The gml:dataSource property describes how the temporal data was acquired. A gml:AbstractTimeSlice instance is a GML object that encapsulates updates of the dynamic—or volatile—properties that reflect some change event; it thus includes only those feature properties that have actually changed due to some process. gml:AbstractTimeSlice basically provides a facility for attribute-level time stamping, in contrast to the object-level time stamping of dynamic feature instances. The time slice can thus be viewed as event or process-oriented, whereas a snapshot is more state or structure-oriented. A timeslice has richer causality, whereas a snapshot merely portrays the status of the whole. A generic sequence of events constitute a gml:history of an object. The gml:history element contains a set of elements in the substitution group headed by the abstract element gml:AbstractTimeSlice, representing the time-varying properties of interest. The history property of a dynamic feature associates a feature instance with a sequence of time slices (i.e. change events) that encapsulate the evolution of the feature.