Co-099 geometric design alternatives for topographic 3 d maps inspired by hand-painted panoramas

When creating digital topographic 3D maps, mapmakers encounter a number of challenges related to occlusion, foreshortening and viewpoint selection. In this paper, we present methods to geometrically deform 2.5D digital elevation models to mitigate such problems. Our methods are inspired by manual techniques of panorama painters. Our algorithms allow the cartographer to interactively apply global progressive and local deformation to a digital terrain model. To demonstrate our methods, we present a series of digital 3D maps that imitate a hand-painted panorama. INTRODUCTION With strong resemblance to the way we perceive and mentally picture space, the 3D map harbors great potential to become a very effective and entertaining medium to clarify spatial circumstances. Yet, cartographers struggle with a number of problems when digitally creating and designing 3D maps. Such challenges include for example occlusion of important landscape elements or reduction of essential map objects due to perspective foreshortening. We hope to help establish and promote this promising type of cartographic representation by improving its geometric design and production process with unconventional solutions. Our approach to finding these solutions is to deduce them from the techniques used in hand-painted panoramas. Panorama painters often apply geometric distortions when designing skiing and hiking maps. In digital 3D maps created with standard 3D rendering and modeling software, such geometric deformations are largely absent. Such software packages do not sufficiently support the specialized deformation and rendering functionalities needed by cartographers. In this contribution, we identify the challenges encountered by digital 3D mapmakers that can be solved by applying geometric terrain distortion. Our digital deformation methods are inspired by analyzing the techniques of panorama painters and bringing them to the digital realm. The resulting prototype software Terrain Bender is especially targeted at deforming 2.5D digital elevation models and allows the cartographer to interactively apply global and local surface bending. The user can also add horizon bending and generate bent cylindrical projections. Our methods can be applied to arbitrary regions, perform at interactive speed and do not require artistic talent or knowledge on rendering systems. TYPICAL 3D MAP MAKING CHALLENGES AND MANUAL SOLUTIONS In the following section, we have a closer look at typical problems encountered by authors of oblique cartographic representations. Such challenges occur when creating panoramas manually as well as digitally. To find inspiration for geometric deformation algorithms, we observe how panorama painters master these challenges in their hand-painted works. An often-encountered problem is that the …