Analysis of temporal information in GML

In gml3, temporal information can be expressed. The time pattern in gml3 extends the core elements of GML to include elements that can describe the time features of geographic data. The purpose is to describe and define the structure of a language, that is, to provide a method for describing the history of a dynamic, element-based time model, these structures are expressed in XML mode or the lifecycle of a collection of elements. The basic time-space model is designed to adjust the timestamps of the element layer and attribute layer, and supports tracking of moving objects.

The temporal pattern consists of Temporal. XSD and temporalcomplexes. XSD pattern documents. They use the <include> element to introduce the definition and declaration in the composite unit pattern units. XSD.

The GML temporal pattern consists of components that describe ry and topology, temporal reference system, and temporal features of geographical data. The representation model constitutes a specialized standard for conceptual patterns. The basic time-space model is designed to provide time stamping for feature-level and Attribute-level, and supports tracking and moving targets.

Time has two types of scales: interval and order. The interval scale provides the basis for the continuity of the measurement time; the Order scale provides the relative location information of the time (for example, a formation sequence or geological time scale ).

The other two ISO standards related to the description of temporal objects are: ISO 8601, which describes the time instants and time periods as the encoding of text strings with special structures and punctuations. ISO 11404, a detailed description of time intervals, is part of a general discussion of language-independent data types.

The temporal pattern consists of two related topics: the three pattern documents provide the basic elements that represent the time, time period, temporal topology, and reference system; A more specialized pattern document component that represents dynamic elements. It is the hierarchical structure of the temporal pattern in GML.

 

The temporal pattern in GML is summarized. Timeobject is an abstract superclass mapped to the abstractgmltype definition in the schema. The abstract subclass timeprimitive is used to represent time ry and Topology objects. However, currently, only the type of geometric units is defined to provide information about time locations. Timeinstant and timeperiod are two geometric units in the time dimension and time period dimension. These classes are mapped to the definitions of timeinstanttype and timeperiodtype modes respectively. A moment is a zero-dimensional geometric representation of the time position (corresponding to a point in space ). A period is a one-dimensional geometric representation of the time range (corresponding to the curve in space); it is an open interval between the starting and ending positions (that is, the moment, and has a length (that is, the duration ). Class timereferencesystem, and its two subclasses are used to define the time reference system. Timeordinalera is used to define the pattern component corresponding to the time reference system. The timeduration class is the basic type that describes the length of time.