Challenges in adapting example-based texture synthesis for panoramic map creation: a case study

Abstract

Panoramic hiking and skiing maps are popular among tourists and map collectors. Such three-dimensional (3D) maps allow for easy orientation and provide the observer with an immersive impression of the landscape to be discovered or remembered. The most impressive panoramic masterpieces are almost exclusively painted manually or with minor digital tool support. Software packages that allow modern cartographers to create 3D maps of comparable visual quality (semi-) automatically are currently not available. Computer graphics has developed a number of methods for painterly rendering, including imitating the characteristics of a panorama artist's brush stroke and raster-based methods that synthesize new texture from examples. In this article, the latter approach is explored, and the idea of creating terrain textures for arbitrary regions by reassembling them from pieces of scanned hand-painted masterworks is pursued. Panorama painters vary the appearance of land cover depending on terrain characteristics and viewing parameters. This article suggests how the example-based texture synthesis approach could be adapted to accommodate such dependencies. A case study of transferring the appearance of H.C. Berann's hand-painted panorama of the Swiss Jungfrau region to a digital panorama of a different region is presented. The case study shows that a number of previously unanticipated hurdles are encountered when using hand-painted panoramas as input to an example-based texture synthesis algorithm. By identifying the challenges of applying texture-by-example to panoramic map making and by suggesting possible solutions, the authors aim to promote the creation of more visually appealing and legible digital panoramic maps.