From 3D City Modelling to 3D Country Modelling: First Tests on Scale-Dependent Rendering on Mobile Devices

摘要: To date, 3D City Models have been confined to well defined city boundaries, and as yet not considered in a multi-city integrated manner, at country scale beyond would be the case for 2D spatial information. However, increasingly National Mapping Cadastral Agencies (responsible generating country-wide mapping) are investigating possibility, financial feasibility utility of making such datasets available over broader area. The potential size detail has led challenge when rendering data on mobile devices understanding limitations usability models these is particularly important given broadening range applications—such pollution or noise modelling, tourism, planning, solar potential—for which resulting visualisations can utilized. This chapter describes preliminary work carried out compare two approaches test area Sheffield (in UK Midlands). stored database triangles then extracted served web-based stream queried by an App developed device (using Android environment, Java OpenGL graphics). Current suggest loading full model onto interacting (e.g. zooming panning) with memory. it suggested that, particular lower specification devices, this may cause memory issues we standard approach second, dynamic, where subset downloaded rendered each time user zooms pans around model, generalised being used larger extents data. Results 24 s (dynamic dataset) versus 54 (full initial download time, 7 0.2 zoom pan operations, highlight fact that dynamic querying managing smaller but further still required.