ISO 19289:2015指出了各种传感器的暴露规则，但如果不满足这些条件，应该怎么做？有些网站不遵守推荐的暴露规则。因此，已建立分类，以帮助确定给定场地在小范围内的代表性（周围环境的影响）。 分类过程有助于网络的参与者和管理者更好地考虑曝光规则，因此通常会改进选址。至少，选址环境是已知的，并记录在元数据中。 显然，完全记录站点是可能的，并且建议这样做，但风险在于，完全记录的站点可能会增加元数据的复杂性，这通常会限制其操作使用。这就是为什么该选址分类被定义为浓缩信息并促进元数据信息的操作使用。 一个网站作为一个整体没有单一的分类号。在现场测量的每个参数都有自己的类别，有时与其他参数不同。如果需要对场地进行全局分类，则可以使用参数类别的最大值。 在ISO 19289:2015中，分类（偶尔）完成时，由于选址的原因，必须将其添加到测量的不确定度预算中。这个估计来自书目研究和/或一些比较测试。 该分类的主要目的是记录测量场地附近是否存在障碍物。

ISO 19289:2015 indicates exposure rules for various sensors, but what should be done when these conditions are not fulfilled? There are sites that do not respect the recommended exposure rules. Consequently, a classification has been established to help determine the given site's representativeness on a small scale (impact of the surrounding environment). The classification process helps the actors and managers of a network to better take into consideration the exposure rules and thus it often improves the siting. At least, the siting environment is known and documented in the metadata. It is obviously possible and recommended to fully document the site but the risk is that a fully documented site might increase the complexity of the metadata, which would often restrict their operational use. That is why this siting classification is defined to condense the information and facilitate the operational use of this metadata information. A site as a whole has no single classification number. Each parameter being measured at a site has its own class and is sometimes different from the others. If a global classification of a site is required, the maximum value of the parameters' classes can be used. In ISO 19289:2015, the classification is (occasionally) completed with an estimated uncertainty due to siting, which has to be added in the uncertainty budget of the measurement. This estimation is coming from bibliographic studies and/or some comparative tests. The primary objective of this classification is to document the presence of obstacles close to the measurement site.