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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
Satellite image is the easies way to obtain geographic
information. Generally, average cost of a raw satellite image
is approximately one dollar for each sq km. The important
point here is whether the data which are obtained from
satellite image will give required accuracy in GIS or not.
The strong improvement in space-borne data and
consequently in the reference scale, can be evaluated by
considering the following features:
- from 1 (Ikonos) to 0,61 m (Quick Bird) of panchromatic
resolution at nadir
- from 4 (Ikonos) to 2,44 m (Quick Bird) of multi-spectral
resolution at nadir
- simultaneous panchromatic and multi-spectral acquisitions
- radiometric range of 11 bits (2048 levels of grey) instead of
the usual 8
- panchromatic band ranging from blue to near infrared
The two last characteristics in particular enable, through a
proper spectral and radiometric enhancement (vs. analogical
air photos e.g.) to reach a better contrast, visibility and
information content and then a better target distinction
( Rossi, 2003).
2. GEOGRAPHIC INFORMATION SYSTEM
AND SATELLITE IMAGE
Aerial photographs and data of satellite image are the most
important resources to provide data of GIS in both
Photogrammetry and remote sensing( Onder, 2003).
According to international resources, total cost of data
collecting and processing are 65% of total cost. This shows
how important is data Figure 2 ( Kokturk, 2003).
0 Counseling
HM Study of Preparation
Ollardware
O Software
Bi Data Collecting and Processing
Figure 2. Cost shares by component of GIS
Satellite image involves actual information such as aerial
photos. At the beginning, although satellite images have
usually been used for producing the maps of 1/50000 and
1/100000, today can be used for producing the maps of
1/25000 and 1/5000. Additionally in GIS setting they have
been used as a data resource, which aims at planning
(Figure 3).
In this study, high resolution IKONOS satellite image, which
can be used in GIS, has been selected and planning have been
done in accordance with this.
High resolution satellite imagery on the wide area can be
achieved more repeatedly and economically compared to the
aerial photos ( Jeong et al., 2003 ).
359
Figure 3. Using of satellite image in GIS
As primary future users of image data from 1m satellites, the
photogrammetric mapping and GIS communities have shown
considerable interest in this new technology ( Froser, 1999 ).
Though the production of topographic maps from satellite
image data is basically very similar, it was ignored by the
cartographic community for a long time. It is of course
obvious that the use of satellite remote sensing for the
production and revision of maps is only of interest if the data
can be extracted with the appropriate accuracy, completeness
and reliability. This however has to be examined. It is
reasonable for related investigations to study the two major
elements of topography, i.e. planimetric mapping and the
height measurements, separately ( Albertz and Wiedeman,
2003).
In a study, it shows that IKONOS imageries can only supply
the data for a preliminary or provisional revision of 1:5000
scale topographic maps or for the rapid but incomplete
revision of existing maps at this scale. Regarding the tests
carried out in this project the IKONOS data seem to be rather
deficient in providing the complete details required for the
production of a final edition of a 1:5000 scale map or for the
comprehensive revision of an existing published map at this
scale. These deficiencies are particularly apparent with regard
to the buildings and small man-made structures. In order to
overcome these deficiencies, which could be as high as 25%
of the total map content in urban areas, a complementary
fieldwork is necessary. The overall evaluation, by taking both
geometric stability and the information content of the image,
seems to indicate the feasibility of a complete map revision
process for the scale of 1/10000 using IKONOS Geo-
panchromatic images ( Samadzadegan et.al,2003 ).
3. CPM-PERT METHOD
Managers can easily estimate total completion time and
finishing time of any projects by means of CPM-PERT
method. Its essential aim is to ease the project planning and
its control, to determine and to remove the free time in the
project and to help to complete the project on planned time.
The method has been developed considering those
unexpected conditions such as bad weather, health and etc.
while doing time estimations and computing total project
time (Ozsu 1986). This method is also used in the cases of
when the exact time of the project activities are not known or
depend on some guesses (Tekin 1992).
