4. CASE: LANDSCAPE ANALYSIS BY USING GRD-
ANALYST
In this article a case project is briefly described. The case is
about landscape analysis in Palojoki area (Nurmijärvi,
Finland). Landscape analysis is made for the purposes of
general/master planning. This project was made by a landscape
architect student and documented in her diploma thesis (Erke,
1995). Intergraph MGE GRID Analyst was used as the
software tool.
4.1 The goal of the project
The goal of the project was to test the GRID-analyst software
tool in landscape analysis. We wanted to identify the most
useful raster analysis functions in GRID and in Tomlins map
algebra. Later on the purpose is to develop a more specified
application for landuse planner. This case was to be as an
prestudy showing the requirements of landscape analyst and
land use planner which should be known in developing an
application.
4.2 Source data
The basic source materials which were used in this case project
were partly received in digital raster form (scanned maps,
classified satellite images, digital aerial photographs) and
partly they were scanned by using a colour scanner. The source
data which were used are listed below:
-digital elevation model (pixel size 25m x 25m),
-base map 1:20 000 in raster form
-topographic map 1:50 000 in raster form
-soil map (scanned)
-classified land use data from satellite image (pixel 25m x 25)
-digital air photo
-copies of historical maps (scanned)
-plan maps and drawings (scanned)
-data from building register (converted to raster format)
-photographs of the area.
Raster maps, satellite images and aerial photographs were
delivered by the National Land Survey.
The first stage in the project was the conversion of different
data sets into the same coordinate system.
4.3 Analysis procedures
The analysis procedures which were made are documented in
the poster. In the following a brief description of the analyses:
4.3.1 Map overlays
Different maps were overlayed in order to see “what there is in
different locations”. In this analysis almost all 2d material was
used.
4.3.2 Digital elevation model -based analyses
On the basis of digital elevation model the southern slopes
were ientified. These areas were combined with the “warm soil
types" classified from the soil map.
The drainage analysis was also made on the basis of the DEM.
4.3.3 The use of classified satellite images
The classified satellite images show different forest types as
well as open areas. The edge areas where for example old
forest or leaf-tree forest meet an open area are important in
landscape analysis and they were calculated in this case study.
In the same way the surroundings of water areas and damp
places were identified.
4.3.4 The use of historical maps
Colour copies of historical maps of the planning area were
available, they were scanned and rectified as well as the data
was classified. They were used to study the change in the open
areas as well as the built areas.
4.3.5 3d visual analysis
The digital elevation model was also used in constructing a 3d
view about the historical situation: the height of the historical
forest are was calculated on the top of the digital elevation
model and a perspective view was then computed. This view
was visually compared with normal perspective photographs
which were taken in the area.
4.4 Conclusions of the case project
By using the grid analyst the planner can make inventories.
Best analysis procedures are typically the simple ones which
can be easily ruled by the planner, it means that the planner
knows what happens and how to interpret the results.
Computational analysis is not always required. A lot of things
can be seen visually (Artimo,1996,1995). Use of colours in
visualization of computations as well as in pure visual analysis
is very important. The use of colours was one of the challenges
in the case project.
S. FUTURE PLANS
Raster analysis seems to be a strong tool. The main advantages
are the easyness of getting source data by scanning, aerial
photography and remote sensing as well as visualizing both
source data and analysis results.
The use of attribute data from registers as well as the linkage
between 2d and 3d data are the future topics of study.
At the moment we are implementing a prototype of land use
planners GIS which is based on raster data analysis and
processing. The goal is to design an easy-to-use user interface
as well as make prototypes of analysis and design procedures
required in land use planning.
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International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996
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