Tachy2GIS_arch
Tachy2GIS_arch
Background
The Saxon State Office for Archaeology (LfA) is the specialist authority for archaeological monument preservation in Saxony and is therefore responsible, among other things, for carrying out all archaeological investigations in the Free State. Tachymeters/total stations are used on a large scale to document (survey) the archaeological finds and features uncovered in the process. This surveying process is to be converted from a CAD-centred approach to the use of geographic information systems (GIS). This requires the development and expansion of software components that enable secure communication between total stations and GIS on the one hand and appropriate utilisation/operation on the other.
Challenge
In addition to the connection of total stations to QGIS, functions should be implemented in the plugin that facilitate work in archaeological surveying. These include the transformation of survey data, the georeferencing of profile images and the digitisation of objects in the georeferenced profile image.
Solution
- QGIS plugin programming with PyQGIS and PyQT
- Algorithms for georeferencing and transformation
- Geopackage as data format
- Release management with OpenProject and GitHub
Implementation
The project management for the development of the QGIS plugin was organised with the help of OpenProject. The various project phases and tasks were efficiently planned and monitored. Release management and continuous software administration was carried out through integration with GitHub, which enabled seamless collaboration and version control. During the course of the project, the development team expanded as excavation teams from the General Directorate for Cultural Heritage Rhineland-Palatinate (GDKE) began to use the plugin. This expansion brought valuable practical experience and feedback into the development process, which contributed to the continuous improvement of the plugin.
The programming of the user interface (GUI) of the plugin was carried out in advance in close coordination with the State Office for Archaeology of Saxony (LfA Saxony). Wireframes and mockups were created to ensure that the specific requirements and usability needs of the excavation survey were taken into account. This coordination enabled a user-friendly design of the plugin.
Various technologies and libraries were used for the technical implementation, including PyQT for the creation of the GUI, PyQGIS for the integration and utilisation of QGIS functionalities, Numpy for numerical calculations and Pillow for image processing. A major technical decision during the project was the switch from the outdated ESRI shapefile format to the more modern Geopackage format. This change offered numerous advantages, such as improved data storage and management.
The benefit
The plugin is now used by excavation technicians in both Saxony and Rhineland-Palatinate. By using this open source plugin, the high licence costs incurred when using proprietary CAD software can be avoided. This leads to considerable cost savings and enables the plugin to be used more widely in various projects and institutions.
In addition, the plugin offers the option of implementing specific algorithms and programme sequences for excavation surveying. These customised solutions can be tailored more precisely to the requirements and challenges of archaeological excavations. The flexibility and adaptability of the plugin help to increase the efficiency and accuracy of the surveying work.
In summary, the plugin not only offers financial benefits by eliminating licence costs, but also technical and operational benefits through the ability to implement special functions and workflows for excavation surveying.