City development in fast motion

Rural expansion of the city of Halle (Saale) analyzed in multimedia and presented interactively

Settlement Development © Institute of Geosciences / University of Halle-Wittenberg
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Whether site analysis, route planning or architectural designs - the geoinformation market is developing rapidly. However, spatial geospatial data not only allow the analysis of current or future developments, but also allow a glimpse into the past. Based on historical documents, it was now possible to analyze the spatial extent of the city Halle an der Saale in a multimedia way and to prepare it as an internet map and interactive learning modules.

"From old cartographic representations continues to be a great fascination, " said Christian Dette Martin-Luther-University Halle-Wittenberg. "However, modern methods of digital cartography today allow this historical material to be spatially processed and adequately presented. In order to do justice to the multimedia demands of today's cartography, the question arises as to how far historical content can be extracted for science and the public and, above all, suitably presented, "explains Dette.

Growth of the city in retrospect

On the occasion of the 1, 200th anniversary of the city of Halle (Saale), therefore, a historical-cartographic analysis of the development of the urban area was made. The scientists of the working group Cartography and Geofernerkundung wanted to show the growth of the city as well as to evaluate the development process statistically. The main focus of attention was on changes in land use as well as in the river networks.

Land use and settlement extension © Institute of Geosciences / University of Halle-Wittenberg

The first step was the research of more than 100 maps from the years 1650 to today. The researchers were able to draw on the extraordinarily rich fund of historical maps of the city of Halle. To make matters worse, however, that almost nationwide representations of today's urban area can only be found from the 19th century. From this, finally 40 cards were selected and extensively processed with digital methods.

Historical card puzzle

"The maps used are extremely different in terms of content and spatial accuracy, " says Dette, explaining the difficulties with the compilation. That required an intensive examination of the historical drawing rules and signatures. But also the knowledge of coordinate systems used at that time and their mathematical foundations were indispensable for the exact evaluation. display

The development of the built-up areas of the city of Halle an der Saale in an overview. Institute of Geosciences / Halle-Wittenberg University

It was also significant that an inaccurate card printing or the age of the card paper could be detrimental, D according to the current state of the art, said Dette. But duplicating and scanning the originals also has certain sources of error, since this can lead to additional inaccuracies. But through successive digital work steps finally managed to adapt the old maps to the current foundations.

Internet maps and learning modules

"In order to enable a universal presentation of the results, we then prepared the content in different levels of detail and interaction", Dette describes the further work steps. In this way, an Internet map with all common functions of a Geographic Information System (GIS), several interactive learning modules as well as a so-called "kiosk variant" with a one-button operation emerged.

In the interests of interactivity and detail, great importance was attached to content and functionality in relation to different target groups. "The user-friendliness of the modules has meanwhile been tested in several exhibitions", explains Dette proudly. With the interactive preparation of the urban settlement development of the city of Halle, we have succeeded in creating a basis for further presentations in the often difficult border area between science and the public.


Urban and settlement development Halle (Saale)

(Christian Dette, Institute of Geosciences, University of Halle-Wittenberg, 03.08.2007 - AHE)