地理标记语言（GML）是符合ISO 19118的XML编码，用于根据ISO 19100系列国际标准中使用的概念建模框架建模的地理信息的传输和存储，包括空间和非空间地理特征的空间属性。 ISO 19136-2:2015定义了XML模式的语法，机制和约定: ？提供一个开放的，供应商中立的框架，用于描述XML中地理信息的传输和存储的地理空间应用模式; ？允许配置文件支持适当的GML框架描述能力子集; ？支持针对专业领域和信息社区的地理空间应用模式的描述; ？实现链接地理应用模式和数据集的创建和维护; ？支持应用模式和数据集的存储和传输; ？增加组织共享地理应用程序模式及其描述信息的能力。 实施者可以决定在GML中存储地理应用程序模式和信息，或者他们可以根据需要决定从其他存储格式转换，并且只对模式和数据传输使用GML。 ISO 19136-2:2015建立在

The Geography Markup Language (GML) is an XML encoding in compliance with ISO 19118 for the transport and storage of geographic information modelled in accordance with the conceptual modelling framework used in the ISO 19100‑ series of International Standards and including both the spatial and non-spatial properties of geographic features. ISO 19136-2:2015 defines the XML Schema syntax, mechanisms and conventions that: ? provide an open, vendor-neutral framework for the description of geospatial application schemas for the transport and storage of geographic information in XML; ? allow profiles that support proper subsets of GML framework descriptive capabilities; ? support the description of geospatial application schemas for specialized domains and information communities; ? enable the creation and maintenance of linked geographic application schemas and datasets; ? support the storage and transport of application schemas and datasets; ? increase the ability of organizations to share geographic application schemas and the information they describe. Implementers may decide to store geographic application schemas and information in GML, or they may decide to convert from some other storage format on demand and use GML only for schema and data transport. ISO 19136-2:2015 builds on ISO 19136:2007 (GML 3.2), and extends it with additional schema components and requirements. NOTE If an ISO 19109 conformant application schema described in UML is used as the basis for the storage and transportation of geographic information, this part of ISO 19136 provides normative rules for the mapping of such an application schema to a GML application schema in XML Schema and, as such, to an XML encoding for data with a logical structure in accordance with the ISO 19109 conformant application schema.