标准编号：ISO 19143:2010
中文名称：地理信息 滤波器编码
英文名称：Geographic information — Filter encoding
发布日期：2010-10
标准范围
This International Standard describes an XML and KVP encoding of a system neutral syntax for expressingprojections, selection and sorting clauses collectively called a query expression.These components are modular and intended to be used together or individually by other standards whichreference this International Standard.EXAMPLE 1 ISO 19142 makes use of some or all of these components.This International Standard defines an abstract component, named AbstractQueryExpression, from whichother specifications can subclass concrete query elements to implement query operations.This International Standard also defines an additional abstract query component, namedAbstractAdhocQueryExpresison, which is derived from AbstractQueryExpression and from which otherspecifications can subclass concrete query elements which follow the following query pattern:An abstract query element from which service specifications can subclass a concrete query element thatimplements a query operation that allows a client to specify a list of resource types, an optional projectionclause, an optional selection clause, and an optional sorting clause to query a subset of resources thatsatisfy the selection clause.This pattern is referred to as an ad hoc query pattern since the server is not aware of the query until it issubmitted for processing. This is in contrast to a stored query expression, which is stored and can be invokedby name or identifier.This International Standard also describes an XML and KVP encoding of a system-neutral representation of aselect clause. The XML representation is easily validated, parsed and transformed into a server-specificlanguage required to retrieve or modify object instances stored in some persistent object store.EXAMPLE 2 An XML encoded filter can be transformed into a WHERE clause for a SQL SELECT statement to fetchdata stored in a SQL-based relational database. Similarly, and XML encoded filter expression can be transformed into anXPath or XPointer expression for fetching data from XML documents.This International Standard defines the XML encoding for the following predicates.a) A standard set of logical predicates: and, or and not.b) A standard set of comparison predicates: equal to, not equal to, less than, less than or equal to, greaterthan, greater than or equal to, like, is null and between.c) A standard set of spatial predicates: equal, disjoint, touches, within, overlaps, crosses, intersects,contains, within a specified distance, beyond a specified distance and BBOX.d) A standard set of temporal predicates: after, before, begins, begun by, contains, during, ends, equals,meets, met by, overlaps and overlapped by.e) A predicate to test whether the identifier of an object matches the specified value.This International Standard defines the XML encoding of metadata that allows a service to declare whichconformance classes, predicates, operators, operands and functions it supports. This metadata is referred toas Filter Capabilities.
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