Florian Ledermann

• Doctor of Engineering
• Senior Lecturer at TU Wien

In this paper we present angular brushing for parallel coordinates (PC) as a new approach to highlighting rational data-properties, i.e., features which - in a non-separable way - depend on two data dimensions. We also demonstrate smooth brushing as an intuitive tool for specifying nonbinary degree-of-interest functions (for focus+context visualiza...

This paper reports findings of a laboratory study that attempts to establish the limits of legibility for fundamental cartographic symbology on modern smartphone screens of varying pixel density. In a controlled setting, participants were asked to discriminate different types of cartographic symbology, while stimulus size was gradually reduced. Fro...

We present a system for running experiments and user studies that can be effortlessly distributed across multiple heterogeneous devices. By taking into account specific requirements of the geosciences (geovisualization, cartography, location-based services), and by providing a clear and simple conceptual model for defining experiments, this system...

This paper compiles guidelines for minimum dimensions of cartographic symbology from the literature on map design for printed and digital maps. Such minimum dimensions are relevant not only for the design of cartographic symbology, but also as fundamental parameters affecting the visual hierarchy of the overall map and the cartographic generalizati...

Analyzing a given map to identify its projection and other geometrical properties has long been an important aspect of cartographic analysis. If explicit information about the projection used in a particular map is not available, the properties of the cartographic transformation can sometimes be reconstructed from the map image. However, such a pro...

Urban areas are characterized by a complex topography of buildings, terrain, vegetation and temporary structures, which, depending on their extent, geometry, geographic location and daytime, cast shadow on their surroundings. Given the importance of sunlight for various groups of interest and tasks, we argue that a comprehensive, accessible, usable...

This Is Not an Atlas gathers more than 40 counter-cartographies from all over the world. This collection shows how maps are created and transformed as a part of political struggle, for critical research or in art and education: from indigenous territories in the Amazon to the anti-eviction movement in San Francisco; from defending commons in Mexico...

This Is Not an Atlas gathers more than 40 counter-cartographies from all over the world. This collection shows how maps are created and transformed as a part of political struggle, for critical research or in art and education: from indigenous territories in the Amazon to the anti-eviction movement in San Francisco; from defending commons in Mexico...

The age of "Big Data" and rapid online publishing brings with it a new need for verifying and understanding digital media. Cartographers are specifically interested in the analysis of maps published online, both with regards to their adherence to established cartographic techniques and for identifying innovative approaches to geographic visualizati...

Many maps on the web do not provide any formal information on the cartographic processes at work in them, despite existing elaborate metadata standards. The key idea of the research presented in this paper is to use the program code of online maps to analyse the transformational processes applied to render them, and to infer cartographic metadata,...

Following Aristotle, F. P. Brooks (1987) emphasizes the distinction between “essential difficulties” and “accidental difficulties” as a key challenge in software engineering. From the point of view of cartography, it would be desirable to identify the cartographic essence of a program, and subject it to additional scrutiny, while its accidental pro...

Creating interactive maps for the web is a complex task. In this paper, we present mapmap.js, our approach to designing a high-level API that supports the creation of interactive thematic maps. We discuss the attributes high-level, transparent, data-driven and horizontal with respect to mapping APIs and argue why these are desirable qualities, and...

The project genderATlas aims to create an interactive online atlas for Austria for a broad range of potential users in which gender-related data is collected, processed and visualised in an innovative and usable way for different spatial dimensions. The main objectives of this project are on the one hand the visualisation of spatial dimensions and...

In this chapter, a domain independent taxonomy of sign functions rooted in an analysis of physical signs found in public space is presented. This knowledge is necessary for the construction of future multimedia systems that are capable of automatically generating complex yet legible graphical responses from an underlying abstract information space...

In this chapter, a domain independent taxonomy of sign functions rooted in an analysis of physical signs found in public space is presented. This knowledge is necessary for the construction of future multimedia systems that are capable of automatically generating complex yet legible graphical responses from an underlying abstract information space...

Mobile augmented reality requires georeferenced data to present world-registered overlays. To cover a wide area and all artifacts and activities, a database containing this information must be created, stored, maintained, delivered, and finally used by the client application. We present a data model and a family of techniques to address these needs...

Augmented Reality (AR) application development is still lacking advanced authoring tools - even the simple presentation of information, which should not require any programming, is not systematically addressed by development tools. Moreover, there is also a severe lack of agreed techniques or best practices for the structuring of AR content. In thi...

In this chapter, a domain independent taxonomy of sign functions rooted in an analysis of physical signs found in public space is presented. This knowledge is necessary for the construction of future multimedia systems that are capable of automatically generating complex yet legible graphical responses from an underlying abstract information space...

In this chapter, a domain independent taxonomy of sign functions rooted in an analysis of physical signs found in public space is presented. This knowledge is necessary for the construction of future multimedia systems that are capable of automatically generating complex yet legible graphical responses from an underlying abstract information space...

Augmented Reality (AR) application development is still lacking advanced authoring tools – even the simple presentation of information, which should not require any programming, is not systematically addressed by development tools. Moreover, there is also a severe lack of agreed techniques or best practices for the structuring of AR content. In thi...

Augmented Reality (AR) can naturally complement mobile computing on wearable devices by providing an intuitive interface to a three-dimensional information space embedded within physical real- ity. Unfortunately, current wearable AR systems are relatively complex, expensive and heavyweight, rendering them unfit for large-scale deploy- ment to untra...

While augmented reality (AR) technology is steadily maturing, application development is still lacking advanced authoring tools - even the simple presentation of information, which should not require any programming, is not systematically addressed by development tools. Moreover, there is also a severe lack of agreed techniques or best practices fo...

In this thesis, the design of APRIL, an XML-based language to create content-rich Augmented Reality (AR) applications and interactive presentations, is presented. The state of the art of hardware and software for AR systems is analyzed, to deduce the key concepts and features of APRIL. One central feature of APRIL is the separation of an applicatio...

In this paper, we present our effort to use augmented reality technology to present an archaeological site inside the "Virtual Showcase". A real scale model of the ruin of the roman "Heidentor" is complemented with virtual overlays to provide the visitor with additional information about the exhibit and interact with it in various ways.

This paper gives an overview of the Virtual Showcase as an augmented reality display system for museums. It explains about different hardware prototypes, interaction tools as well as several software techniques to utilize the features of the Virtual Showcase. It also presents two case studies, one from paleontology and one from archeology.

In this paper, we present our effort to use augmented reality technology to present an archaeological site inside the 'Virtual Showcase'. A scale model of the ruin of the roman 'Heidentor' is complemented with virtual overlays to provide the visitor with additional information about the exhibit and interact with it in various ways. Using a custom a...

A mobile augmented reality system for 3D interaction requires an easy to use, interactive input device. In our work on the Studierstube project, we had long-term experience with two-handed direct manipulation interfaces based on tracked props. However, for a mobile setup, props are no longer appropriate as they permanently occupy the user's hands a...

In our approach to improve tracking availability, tracking data from multiple hosts is shared across the network. Pairwise camera-to-camera relationships are established automatically, as soon as any marker is seen by two cameras, independent of the cameras' placement (e.g. cameras worn by a user or mounted at a "hot spot" location to improve track...

In this paper we present several extensions to the wellknown InfoViz technique of parallel coordinates, mainly concentrating on brushing and focus+context visualization. First, we propose angular brushing as a new approach to high-light rational data-properties, i.e., features which depend on two data dimensions (instead of one). We also demonstrat...

A mobile augmented reality system for 3D interaction requires an easy to use, interactive input device. In our work on the Studierstube project, we had long-term experience with two-handed direct manipulation interfaces based on tracked props. However, for a mobile setup, props are no longer appropriate as they permanently occupy the user's hands a...

While Mixed Reality (MR) technology is steadily matur-ing, application development is still lacking advanced au-thoring tools – even the simple presentation of information, which should not require any programming, is not system-atically addressed by development tools. Moreover, there is also a severe lack of agreed techniques or best practices for...

Today's cities are full of signs: roadsigns, signposts, maps, graffitis, among many others. Future mobile digital information systems used in ur-ban space will add another dense, digital layer of information on top of that, augmenting the user's view with additional visual signs. If we want these envisioned systems to enlighten instead of confuse t...