# Geo-Spatial Context Provision for Digital Twin Generation
## 4 Related Work
### Methodologies for the Creation of Digital Twins
Overall, it was observed that DT design methodologies can be given at many different levels of abstraction and generality. There exist more abstract and general proposals that can be used to describe and structure design and development approaches from a variety of fields and concerning a variety of different flavors of DTs and real-world entities to be twinned (e.g., [45; 47] go in this direction). In general, rough correspondences between the proposed steps of the examined approaches and the ones of our methodology can be identified (e.g., initial steps of purpose definition and selection of assets/process to be twinned in [47], verification and validation steps in [45; 50], iterations for adaption/refinement of the DT in [45; 47; 48]). However, some of the parts of these models (e.g., the last four subprocesses in [45], or the various development steps of the DT V-model in [50]) have not been covered by the proposed development approach to a comparable level of detail. Then, there also exist specific approaches for a certain type of asset (e.g., manufacturing systems [46]), or a certain type of twin (e.g., in terms of content of the twin, such as physics-based models [49]), or even a specific part of the wider DT creation process (e.g., model creation [49]). In relation to the existing research, the introduced methodology for DT design can be also considered as a specific instantiation for a certain class of twin (behavior-centered process twins), with cyber-physical assets being the main real-world entities of interest. The focus on processes from more of a business context is a unique aspect of the introduced methodology (the term \"process\" is also used by some of the examined works with a different comnotation, e.g., in [46] it refers to physical (kinematic) processes). The examination also revealed some of the limits and opportunities for the extension of our proposed methodology. By examining the identified steps of other proposals, certain aspects of design and development were uncovered that were not considered yet. For instance, certain phases related to the continuing CPS and DT life-cycle could be covered in more detail. The different variations for DT development scenarios listed in [50] are particularly interesting, since our proposal for now only covers the case of an existing CPS as entry point for DT creation. The approach in [48] furthermore supports its users through some degree of automation: After the sufficient refinement of models, automatic deployment of the DT can be accomplished. Such support could greatly ease development and adoption efforts. Creating an expanded methodology by taking into consideration and integrating aspects of other approaches is considered progressing the presented research. In this section, we have reviewed some of the related work pertaining to existing DT approaches that use geo-spatial context provided by LiDAR technology and methodologies for the creation of DTs. The focus on approaches outside the field of subject orientation reveals the need for behavior-centered and integrated DT design and engineering. Hence, as outlined in Section 3.1, we utilized existing behavior-centered modeling and execution as basis for extending the knowledge base of subject orientation, and applied this behavior-centered approach for geo-spatial sensitive CPS and DTs, as discussed in the following section.