NDE 4.0 is about evolving the practice of NDE from independent, perhaps automated, measurements into a new world of interconnected information, where the NDE data connects with measurement models, structural models, and part history to provide an integrated perspective on structural health. Registering NDE data to physical, geometric location is essential to connecting it to outside information. While in the past registration would have been a manual and error-prone process, especially for complicated 3D geometries, improved imaging and 3D camera technology are beginning to make automatic registration practicable. This chapter introduces the principles and approaches to registration of NDE data in two and three dimensions, including methods for projecting ray and image data. We discuss the difficulty of accommodating inconsistent geometries and approaches such as persistent parameterizations that may help address such inconsistencies. In order to be accessible, registered NDE data will need to be indexed in a spatial database so that it can be queried by geometric location. Such a database will be more valuable the more NDE and other data can be integrated into it, so common file formats, open metadata, and open-source tools are needed so that the broader NDE community can start embedding the necessary registration metadata into our scans.