International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B4, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
the land-use of Istanbul in 1945, 1968, 1988 and 2000 as the
reference year. To reach this goal, the satellite imagery of the
reference year 2000, satellite photographs of 1988 and aerial
photos of the years 1968 and 1945 had to be pre-processed to
get them properly georeferenced. The second step has been the
digitisation and interpretation in GIS environment. In the final
step the interpretation took place. Istanbul is growing enormous
and the change is really dramatic. In relation to other European
cities, Istanbul as a gate to the east and the Islamic world has a
bridge function and a very specific development. The
development went not homogenous. Especially between 68 and
88, grow has been the biggest. However the population growth
has been high on a homogenous level, which means that the
population density grew. The increase of urban fabric however
needs to be compensated by other area, in the case of Istanbul
similar to other big cities, by the loss of agricultural land. This
will be pointed out in this paper. The total project area was
3100 km?.
3. DIGITALISATION AND
INTERPRETATION
All digitisation and interpretation work was done manually on-
screen. Automatic processes for feature extraction in urban
areas fail if such a detailed legendary is recommended.
70 70 £3 0m I nn Io fo I 10 10 10 1010 10 19 FORO Min bn ba ba iai
Line-Layer: First the linear elements (lines and polylines),
such as transportation (road and rail) and river/sea-canal
network, have been mapped according the MOLAND legendary
on screen by using TOPOL GlSystem. topological data-
structure has been used. Limit was given by the visibility in the
satellite-imageries. More wide linear features have been
digitised by a middle line and as far as they have a bigger width
than 25 m, they have been mapped in the area-layer as well. The
attribute database was opened after the line was drawn. Then
the topological structure by creation of nod-points has been
established. These lines are often boundaries for area-objects.
So far they have been copied to the file with the area-database
of the processed year.
Area-Layer: The lines and polylines of the line-layer have
been used as basement for the arca-layer (polygon with label-
point). All other areas with a homogeneous use according to the
legendary have been defined by the boundary-line and the
labelling-point with the attached database in its middle. Also
here topological mapping was required to reduce the work and
the risk, which can appear, by redundant lines. Also the snap-
mode has been set to lines and vertex points in a suitable radius
to fill entire project area without macro rest polygons. The
database was filled during defining the label-point inside the
boundary. An additional area-layer, a so-called 3d-layer, was
added to take area objects into account, which cover other area
objects. These are namely big bridges and highway tunnels.
These elements are on one side connected correctly by the
middle-line in the line layer and further on by a direct
neighbourhood to a related object in the area layer. The snap
mode has been enabled to snap to other, non-active layers as
well to keep a semi-topological structure.
Temporal analyses have been undertaken by down-dating the
land-use-classes of the 3 layers by going back-wards to 1988,
1965 and 1945. Finally 4 line layers, 4 area layers and 4 3d
area-layers have been developed. Using database-analyses and
GIS-intersections the changes can be detected and quantified.
Fist the entire line layer had to be down-dated by the older
images. Additional line-objects have been added and others
been erased. The database had to be checked if the object
attributes still fit to the legendary. Then the down-dated lines
and the lines of the newer area layer have been imported into a
new empty layer.
Figure 1: Example of the digitised transportation network on
the left (Highways in red, other road in pink) and the lad-use
data set on the right with the legendary of the classes (red =
residential, pink = business)
To import the database just for information, only the label
points with attached area database have bcen copied. Then also
here the lines have been corrected as boundary lines. As far as
the area and the use was the same, the area had been created
automatically and the attributes taken from the point database.
336
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