Clients:
Ministry for the Environment, Nature Protection, and Spatial
Planning, Brandenburg, Germany
Lausitzer und Mitteldeutsche Bergbauverwaltungsgesellschaft
(LMBV)
Lausitzer Braunkohle AG (LAUBAG)
Introduction
Geographically the East German brown coal deposits which are the
largest in Germany are located in the Halle / Leipzig / Bitterfeld
region and in the Lausitz region near the Polish border. In the
Lausitz region the brown coal seam reaches an average thickness of 12
m. The seam is covered by an overlay shelf of 40 m - 107 m in
thickness which can be removed by gigantic excavators. With 650 m in
length the excavators used in the Lausitz region are the largest
movable man-made structures on earth. Up to 60 m in depth can be
removed in one step.
Because of the decreasing demand for brown coal most of the surface
mining activities will not be continued in the future.
Effects on the Environment
Large parts of former East Germany are shaped through brown coal
surface mining activities. The most dramatic effects on the
environment are related to groundwater, air quality, and the visual
quality of the landscape.
Naturally the landscape is an agricultural landscape with large
forested sections. During the four phases of the surface mining
process (exploration, development, production, and reclamation) the
relatively flat landscape is transformed into a landscape of
completely different character. In the case of the pilot study
'Jänschwalde' the zone of active mining is moving north leaving
an area of approximately 24 km2 in the south to be reclaimed. In this
section there are two very large depressions (90 m relative to the
surroundings) of 4 km respectively 2 km in length and 800 m in width
[place here fig. 1]. Extensive pumping of groundwater of up
to 170 m3 per minute prevent the holes from being flooded. The
reclamation involves massive terrain alterations for stability and
safety reasons. Because of the highly acid soil conditions (pH 3 or
less is possible) after the terrain modelling also soil improvement
measures are essential as a prerequisite for further land use like
forestry or agriculture. Reclamation of such large areas take a long
time. By the year 2010 the smaller one of the two depressions is to
be filled in and the larger one to be flooded by the natural rise of
the groundwater level. In 2030 the whole area will be reclaimed.
Major Goals of the Pilot Study
Major goals of the pilot study 'Dynamic visual simulation -
reclamation surface mining site Jänschwalde' (HEHL-LANGE &
LANGE 1996) are to explore ways how existing data (terrrain data,
satellite imagery) can be utilized and how landscape change can be
visualized in three dimensions over time. The visualizations shall be
used as the basis for the design of the new landscape and as a means
of communication among the numerous involved institutions.
Our Approach
GIS - systems are mostly 2D oriented, whereas the strength of
visualization systems is due to the capability of dealing with the
3rd dimension. In the case of the brown coal pilot study only the
terrain data which is needed in the mining and reclamation process,
is captured in three dimensions. Most other data is in 2D format.
Automatic procedures for generating 3D objects from 2D data, i.e.
having the 3D modelling based on numeric data from the GIS database,
can bridge the gap between the mainly 2D GIS systems and 3D
visualization systems (HOINKES & LANGE 1995). In the presented
example (using Polytrim software from CLR University of Toronto)
3D-objects like trees and buildings can be generated directly through
largely automated procedures. In order to perform this task
attributed 2D data is needed, e.g. containing the height of a
building structure, which is used as the basis for the creation of
the 3D-objects which are then set on the terrain. Using this
technique a unification of various (partly) existing data sources
like photogrammetric data acquired by the mining companies, satellite
imagery, and also an integration of 2D reclamation plans and data
derived from topographic maps into a virtual landscape model is
achieved.
The virtual landscape consists of a digital terrain model at 10 m
resolution with a draped satellite image and 3D-Objects like single
trees, forests and buildings. Image data was available from Russian
KFA-1000 (5-7 m resolution) and Russian KWR - 1000 (max. 1.5 m
resolution, B/W) satellites as well as LANDSAT TM (30 m resolution)
imagery. Most appropriate were the KFA-1000 images. Although the
color range lies in the near infrared range, the appearance was
improved through filtering.
Visualizing Change
Visualization is also the common denominator for incorporating
the factor time into the model through the representation of the
different development stages between 1940 - 1995 - 2010 - 2030.
Additionally two design alternatives for the future are worked out.
Through actively designing vistas by altering the terrain and the
vegetation scheme instead of plain afforestations the potential for
recreation is improved.
As there is no satellite imagery available dating that far back or
ahead the existing scene was registered and overlaid with digitized
land use information covering the past and the future. Using image
processing techniques geotypical textures were applied according to
the different time phases.
As a result several animations (fly-through, driving car, pedestrian)
are produced which allow the comparison of the different time phases
and different design alternatives. The animations are recorded on
video at a rate of 50 frames / second totalling 10 minutes of
animated sequences corresponding to 40 GB of calculated images.
Conclusions
The visualizations which can be generated based on the virtual
model are an essential means of communication among the various
involved experts from different disciplines and the general public.
By providing a common basis for discussion the decision making
process can be optimized (see e.g. LANGE 1994).
Compared with an interactive presentation using a computer, video is
a relatively static medium where the observer has to follow a
predefined animation path. In order to increase the degree of realism
in future applications high resolution aerial orthophotography should
be used (see e.g. KERSTEN & O'SULLIVAN 1996).
Although the presented results where appreciated highly by the
involved ministry and the coal mining companies there is a fair
danger that other than this study not much more will happen in the
future. The size of these institutions and the widely distributed
responsibilities could possibly lead to an inability of these
institutions towards an incorporation of new planning techniques.
Effectively applying these 3D visualization techniques would require
a different understanding of the planning process.
Link to some more figures (AGIT '97-Posters)
Back to Eckart Lange
Back to Sigrid Hehl-Lange