International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B2. Istanbul 2004
the borders of the roads can not be demonstrated by
exaggerating in the orthophoto maps. All natural and artificial
features are indicated in their original and real sizes in the
nature. Against this, all features are demonstrated by
exaggerating on the vector maps in order to interpret the map
and detect the features easily. Additionally, when going further
away from the photographic centre point, the image tilting
errors happen because of appearing of side surfaces of some
high features and natural details such as hills, buildings,
suspended bridges, block rocks, towers etc (OEEPE Official
Publications, No: 25, 1991).
Orthophotos and orthophoto maps are mainly used for the
creation of a raster GIS data base. They can be in analogue or
digital form. If it is necessary, the graphic vector data belonging
to the features can be manually digitized from the analog
orthophoto maps placed on the digitizing tablet or they can be
collected from the digital orthophoto maps with the use of the
heads-up digitization method.
2.8 Image Maps
An image map is produced by adding various cartographic
elements such as region/mountain/hill/stream names, other
geographic place and feature names, grid lines and other
cartographic map sheet border information to an ortho-rectified
satellite image (ortho image). This map is usually produced in
the dimensions and scales of the standard topographic maps.
The image maps are completely similar to the orthophoto maps
in view of the use and properties. Optimum/ideal ortho-image
and image map scales to be produced from various satellite
images commonly used in the world in today’s are indicated in
Table-3 (Baltsavias, 1993).
SATELLITE PIXEL IDEAL ORTHO
IMAGE TYPE SIZE IMAGE MAP
SCALE
LANDSAT- 80m 1/250.000
1,2,3,4,5 MSS
LANDSAT- 30 m 1/100.000
1.2.3455 TM
SPOT-1,2,3,4 XS 20m 1/100.000
SPOT-1,2,3,4 P 10 m 1/50.000
KFA-1000 5-10 m 1/25-50.000
KVR-1000 2m 1/10-25.000
MOMS-02 4.5m 1/25-50.000
ERS-1/2 Radar 30m 1/100.000
IRS-1C 6m 1/50.000
LANDSAT-7 MSS | 30m 1/100.000
LANDSAT-7 TM 15m 1/50-100.000
SPOT-5 XS 20m 1/100.000
SPOT-5 P 10 m 1/50.000
SPOT-6 P 10 m 1/50.000
IKONOS P I m 1/5-10.000
IKONOS MSS 4m 1/25-50.000
QUICKBIRD P 0.61-0.8 m 1/5.000
QUICKBIRD MSS | 2m 1/10-25.000
Table 3. Suitable map scales recommended for the production
and revision of ortho image maps from various satellite images
2.9 Digital Elevation Model (DEM) Data
DEM data contains the selection and measurement of the cluster
of points which reflect the real shape of the ground surface in a
suitable way. For using DEM data in a GIS data base, it is an
appropriate way to take of DEM point configuration and
densification as a grid network form. The resampling points
used in DEM can be in the form of irregular points taken in the
ground surface, points taken on the structure lines and
breaklines, the characteristic points taken in the ground surface
or intersection points of the grid network. In order to collect
DEM data, various data collection methods are used. These
methods are the geodetic, topographic, tacheometric and
photogrammetric methods, the digitization of existing maps and
plans, the data collection with the systems mounted on the aerial
vehicles and platforms (aircrafts and satellites) and finally, the
combination of these data collection methods (Gruen, 1998).
The production of DEM consists of three different processing
steps: These are the data collection (measurement and capture),
data processing (evaluation) and data presentation (displaying
and printing). DEM data have widely being used in the
topographic map production and all kinds of non-topographic
activities. By using stereo aerial photographs and satellite
images, necessary DEM data can be collected with manual and
semi automatic data collection methods by using the absolute
oriented stereo models prepared in the analytical sterco plotters
and with manual, semi-automatic and automatic data collection
methods by using the stereo models prepared in the digital
stereo plotters with the use of digital image matching techniques
(Alkis and Ozer, 1996).
2.10 Existing Digital Map, GDB and GIS Data
The existing digital maps, GDB or GIS data, graphic and non-
graphic information can be transferred directly into a new GIS.
If the existing digital maps are not up-to-date, firstly, they
should be revised by using up-to-date data resources (generally
aerial photographs). This digital data resources mentioned above
are used as the basic and original sheet layout in the computer
supported map revision. The digital map data collected by few
reliable resources are the data which can be used directly in
establishing of a GIS. In the case of the digital map data are
available, their revisions can be performed in a very short time
and economically. Thus, a great speed and economy can be
provided in forming of a GIS. The most important deficiency of
the existing digital maps is generally not to contain the attribute
information belonging to the topographic features. The existing
GDB and GIS data don't usually have this disadvantage, but
revision of this data and adding of some new information is
necessary (Bank et.all, 1995).
2.11 Atlases
In view of their structures, the atlases are the documents which
contain some graphic, thematic and attribute data relating to
some topics. But, the graphic data existed in the atlases are
generally used in establishing of a GIS which are related to
small scale maps such as 1/500.000 and 1/1.000.000. In the
processes of establishing a GIS related to 1/25.000 or larger
scale maps, various attribute information and thematic data
existed in the atlases (such as the geographic feature and place
names, road types, the names of urban areas and cities) can be
used. The data obtained from the atlases are usually
complementary data of a GIS and used generally as the
secondary data resources (Ozbalmumcu, 1999).
2.12 Geographic Feature Names Catalogue (Gazetteers)
These documents generally contain up-to-date names of
geographic locations, urban, rural and regional area, natural and
artificial features such as hills, mountains, bridges, roads, towers
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