Lorenz Hurni

Cultural Heritage: Studying cartographic heritage: Analysis and visualization of geometric distortions

Old maps are increasingly used as a source for historical research. This is a consequence of the increased availability of old maps in digital form, of the emergence of user-friendly Geographical Information Systems, and of a heightened awareness of the unique information stored in old maps. As with every source for historical studies, when old maps are georeferenced and information is extracted for historical research, the accuracy and reliability of the geometric and semantic information must be assessed. In this paper, a method based on a series of geometric transformations is presented, which transforms control points of a modern reference map to the coordinate system of an old map. Based on these transformed points, the planimetric and geodetic accuracy of the old map can be computationally analyzed and various visualizations of space deformation can be generated. The results are graphical representations of map distortion, such as distortion grids or displacement vectors, as well as statistical and geodetic measures describing the map geometry (e.g., map scale, rotation angle, and map projection). The visualizations help to assess the geometric accuracy of historical geographical information before using the data for geo-historical studies. The visualizations can also provide valuable information to the map historian about the history of a particular map and its creation.

Orthophoto generation using IKONOS imagery and high-resolution DEM: a case study on volcanic hazard monitoring of Nisyros Island (Greece)

Georeferenced high-resolution satellite images can be used for acquisition of topographic information, navigation and visualisation for various environmental studies. The present study is part of the multidisciplinary EU project GEOWARN related to monitoring, warning and emergency planning for volcanic hazards in the island of Nisyros, Greece. Here, the main aim was the orthorectification of a 1-m resolution pan-sharpened IKONOS Geo image of Nisyros island. For the orthorectification, a digital elevation model (DEM) with a cell size of 2 m and an RMS accuracy of ca. 3.5 m was used, as well as 38 selected ground control points (GCPs) measured with differential GPS. An object-to-pixel space transformation using the ground control points was computed using two different models, a relief-corrected affine transformation and the polynomial mapping functions of Kratky. These transformations were used for orthorectification and the orthophoto accuracy was evaluated using GCPs as check points. Postprocessing for radiometric improvement of the orthophotos was applied. The orthophoto and the DEM served as basic tools for subsequent base mapping and visualisation. D 2002 Elsevier Science B.V. All rights reserved.

An interactive map to assess the potential spread of Lymnaea truncatula and the free-living stages of Fasciola hepatica in Switzerland.

The intermediate host of Fasciola hepatica is Lymnaea truncatula in Switzerland. The snail and the free-living stages of the parasite require a moderate climate and moisture for survival, reproduction, and transmission. In Switzerland, these conditions are present in many regions, resulting in a mean prevalence of bovine fasciolosis from 8.4 to 21.4%. An interactive map was created in order to demonstrate the relative risk of transmission by modelling the environmental conditions that promote the survival and reproduction of the larval stages of the parasite and the parasites intermediate host. The map is based on temperature and rainfall data, soil conditions including ground water and forest cover in Switzerland. Extensive information on the free-living stages of F. hepatica and the intermediate host L. truncatula and how the development of these are affected by these environmental factors was used to create the interactive risk map.

Mapping Literature: Towards a Geography of Fiction

Modern cartography has the ability to map almost any phenomenon for which spatial relationships are of primary relevance. While existing cartographic products cover already an enormous variety of topics, the visualisation of ‘other’ geographies gains more and more attention. These other geographies may not accord to the ‘normal’ spaces usually mapped, hence cartography is both challenged and forced to find uncommon solutions. Literature and its fictional spaces might serve as a fi ne example (but one could also think of soundscapes or emotions). Doubtlessly, the realm of fiction is defined by different ‘rules’ to the geography that cartography customarily addresses. This paper deals with two main questions: Firstly, how to map narratives and their complex spatial structure? Secondly, what do we achieve by mapping literature? By searching for some (provisional) answers, the horizon of a promising interdisciplinary research field – a future literary geography – becomes visible.

Proposed Cartographic Design Principles for 3D Maps: A Contribution to an Extended Cartographic Theory

Today, the technical generation of modern perspective views (so-called 3D maps) for static, animated, and dynamic use is highly advanced. Nevertheless, aspects of the design of such views and of their impact on readers have rarely been investigated in cartographic research. The establishment of cartographic design principles is missing, to a large extent. Within the framework of a research project, propositions for such principles were derived by evaluating settings and options for specific graphic variables. Based on an inventory of design aspects and graphic variables for 3D maps, selected cues for two major design aspects (degree of abstraction and size of map objects) and five different graphic variables (viewing inclination, zoom factor, light direction, haze density, and sky structure) were evaluated by means of 3D map examples and expert interviews. A set of cartographic design principles was derived from this evaluation and proposed for more detailed user tests. The proposed design principles coul...

On the Design of Schematic Transport Maps

Abstract Schematic drawings of route directions are one of the most common forms of graphic communication. People make sketches to communicate geographical ideas, and professionally designed schematic maps give orientation to thousands of users of a public transport system. Creating a schematic map for representing a transport network may be seen as a straightforward task; however, the underlying design of such maps can be quite complex. Map designers apply, consciously or subconsciously, various cartographic generalization techniques to emphasize important information and to improve the clarity of map content. At present, traditional mapping and GIS literature offers very little guidance to a map designer seeking cartographic rules or practical ideas for representing the elaborate route data of public transport systems schematically. This article aims to contribute to the design challenges of schematic, route-based mapping. Information about schematic maps and symbolization of route-based data is given. ...

Web cartography with open standards - A solution to cartographic challenges of environmental management

The visualization of spatial information in the form of maps is a critical task to facilitate decision making in environmental management. Web Map Services (WMS), Styled Layer Descriptor (SLD) and Symbology Encoding (SE) already created an open framework for Web mapping services. However, from the cartographic point of view, the OGC standards have several limitations for producing high quality cartographic representations. Fortunately, these standards can be cartographically enriched to fulfil the complex visualization requirements coming from environmental management. A solution to creating cartographic visualizations based on open standards was developed in the frame of two major European projects, namely ORCHESTRA (Open Architecture and Spatial Data Infrastructure for Risk Management) and SANY (Sensors Anywhere). For example, the IST - 6th Framework Integrated Project SANY, focuses on interoperability of in situ sensors and sensor networks. In this context, sensors serve as an extreme illustration for the dynamic nature of spatial information that must be represented in the form of maps. The cartographic extensions for the Symbology Encoding (SE) standards allow expressing cartographic rules with spatial operators and advanced feature filtering for layer masking, flexible point symbolization, and patterns and gradients for all spatial features. Furthermore the critical point of creating thematic maps is also solved with extensions for intuitive choropleth and various diagram types generation.

Visualizing the Planimetric Accuracy of Historical Maps with MapAnalyst

MapAnalyst is a new software application for the visualization and study of the planimetric accuracy of old maps. It illustrates local map distortion by generating distortion grids, displacement vectors, and new isolines of scale and rotation. MapAnalyst additionally computes the old maps scale and rotation, as well as statistical indicators summarizing the maps geometric accuracy. It offers a user-friendly interface and is freely available for all major computer platforms at . Map historians are invited to use MapAnalyst, and are encouraged to consult and improve the free Java source-code. This article describes the steps leading to visualizations of a maps planimetric accuracy. It provides basic algorithmic information that is necessary for the understanding and correct interpretation of displacement vectors and distortion grids. It also introduces isolines of equal scale and rotation, a new type of accuracy visualization. The last section interprets sample visualizations for an eighteenth century map.

An interactive, web-based, real-time hydrological map information system

Abstract Hydrologists responsible for flood management need real-time data in order to manage imminent or ongoing floods. In this paper, innovative methods for accessing hydrological data and their spatial visualization are introduced. A multitude of relevant real-time, forecast and historical information is provided in a single, self-updating hydrological map information system. The system consists of a central database and a cartographic user interface and provides harmonized and filtered data in the form of interactive, customizable maps. Maps may also be cross-referenced with historical maps or may be animated for improved comprehension and decision making. Emphasis is placed on the development of the hydrological real-time database that manages large amounts of spatial, temporal and attributive data. The paper focuses on the cartographic user interface, its functionality and the resulting interactive hydrological maps. Citation Lienert, C., Weingartner, R. & Hurni, L. (2011) An interactive, web-based, real-time hydrological map information system. Hydrol. Sci. J. 56(1), 1–16

Flex Projector–Interactive Software for Designing World Map Projections

Flex Projector is a free, open-source, and cross-platform software application that allows cartographers to interactively design custom projections for small-scale world maps. It specializes in cylindrical, and pseudocylindrical projections, as well as polyconical projections with curved parallels. Giving meridians non-uniform spacing is an option for all classes of projections. The interface of Flex Projector enables cartographers to shape the projection graticule, and provides visual and numerical feedback to judge its distortion properties. The intended users of Flex Projector are those without specialized mathematical expertise, including practicing mapmakers and cartography students. The pages that follow discuss why the authors developed Flex Projector, give an overview of its features, and introduce two new map projections created by the authors with this new software: the A4 and the Natural Earth projection.