CITYGML RESTFUL WEB SERVICE: AUTOMATIC RETRIEVAL OF CITYGML DATA BASED ON THEIR SEMANTICS. PRINCIPLES, GUIDELINES AND BLDG CONCEPTUAL DESIGN

CityGML is considered an optimal standard for the representation of 3D city models. However, due to its complex structure, easy-to–use data retrieval is important, in terms of interoperability. This implies choosing the implementation of Web Service Technologies and in particular the WFS, as the most suitable OGC standard for retrieving the real geometry data. Nevertheless, this standard serves data mainly based on their geometry, while CityGML also covers topology and more importantly semantic aspects of 3D city models. Therefore, this paper examines and presents the new CityGML RESTful Web service, instead of the OGC WFS. This Web Service is conceptually designed to achieve CityGML data retrieval based on their semantics characteristics. In this context, several principles and guidelines of the new CityGML RESTful Web service are described and the “CityModels” resource is presented. Additionally, the conceptual design of the bldg resource and its child resources based on the level of details is also presented

Single ionization of helium by 102 eV electron impact: three-dimensional images for electron emission

Single ionization of helium by 102 eV electron impact has been studied by measuring the momentum vectors of all final-state particles, i.e., two electrons and the He + ion, with an advanced reaction microscope. Fully differential cross sections for asymmetric scattering geometry, which have been normalized to an absolute scale, have been obtained covering a large range of emission angles for the emitted low-energy (E ≤ 15 eV) electron and different scattering angles for the fast electron. Strong electron emission out of the projectile scattering plane is confirmed for electron impact, as was observed before for heavy-ion impact ionization. The data are compared with theoretical predictions from a three-Coulomb wavefunction model, first-order and second-order distorted-wave approaches, as well as a convergent close-coupling calculation