When QGIS 3.0 was released in 2018, it added support for 3D visualisation. At the same time, CityJSON has been developing as an easy‐to‐use JavaScript Object Notation (JSON) encoding for 3D city models using the CityGML 2.0 data model. Together, this opened the possibility to support semantic 3D city models in the popular open‐source GIS software for the first time. In order to add support for 3D city models in QGIS, we have developed a plugin that enables CityJSON datasets to be loaded. The plugin parses a CityJSON file and analyses its tree structure to identify all city objects. Then, the geometry and attributes of every city object are transformed into QGIS features and divided into layers according to user preferences. CityJSON parsing was proven to be straightforward and consistent when tested against several open datasets. One of the biggest challenges we faced, though, was mapping CityJSON’s hierarchical data structure to the relational model of QGIS. We undertook this issue by providing various methods on how geometries from the model are loaded as QGIS features. We intend to use the plugin for educational purposes in our university and we believe it can be proven a worthy tool for researchers and practitioners.

中文翻译：

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QGIS 中的 CityJSON：开源插件的开发


QGIS 3.0于2018年发布时，增加了对3D可视化的支持。与此同时，CityJSON 一直在开发为一种易于使用的 JavaScript 对象表示法 (JSON) 编码，用于使用 CityGML 2.0 数据模型的 3D 城市模型。总之，这首次为流行的开源 GIS 软件中支持语义 3D 城市模型提供了可能性。为了在 QGIS 中添加对 3D 城市模型的支持，我们开发了一个插件，可以加载 CityJSON 数据集。该插件解析 CityJSON 文件并分析其树结构以识别所有城市对象。然后，每个城市对象的几何形状和属性被转换为QGIS特征，并根据用户偏好进行分层。在针对多个开放数据集进行测试时，CityJSON 解析被证明是简单且一致的。然而，我们面临的最大挑战之一是将 CityJSON 的分层数据结构映射到 QGIS 的关系模型。我们通过提供各种方法来解决这个问题，如何将模型中的几何图形加载为 QGIS 特征。我们打算在我们的大学中将该插件用于教育目的，我们相信它可以被证明是对研究人员和从业者来说是一个有价值的工具。