| GEODETIC INFRASTRUCTURE OF TURKEY FOR
GIS, GPS AND REMOTE SENSING APPLICATIONS
R. N. Celik *, T. Ayan*, R. Deniz?, M. T. Ozlüdemir?
* ITU, Civil Engineering Faculty, 34469 Maslak Istanbul, Turkey - (celikn, ayan, denizr, tozlu)@itu.edu.tr
Commission VI, WG VI/4
KEY WORDS: Geodesy, Spatial Infrastructure, Reference Data, GIS, GPS, Remote Sensing
ABSTRACT:
What scale is the GIS basic scale? The answer of this question is very important. Since when GIS applications are investigated in
the world today, it is seen that GIS developers’ concepts mainly intersect on small scale applications. However digitals maps scale
is starting from 1 over 1 which represents real dimension. Therefore the resolution and positioning quality of data defines the scale
of applications. If so, GIS scale starting from 1 over 1. In that case GIS concept might be expressed as a pyramid and from bottom
to top, and it might be ordered as Land Information System, Urban Information System and finally Special Purpose GISs. Certainly
there are two main indispensable information structures at the very bottom of this pyramid. They are a precise, reliable and robust
geodetic infrastructure and basic maps respectively. Remote Sensing and Photogrammetry are mainly used as geo-data collection
technologies. Therefore they take place to produce basic maps and related data collections in that definition. So both technologies
need to stand on geodetic infrastructure. Hence this paper has been prepared for transferring information about geodetic
infrastructure of Turkey to the people who would like to carry out GIS, Remote Sensing and Photogrammetric applications in
Turkey. From that point further in this paper reader will obtain detail information about existing coordinate systems and their
responsible institutions in Turkey. More over, way of working with these coordinate systems will be expressed. Thereafter
sufficiency of geodetic infrastructure of Turkey will be discussed for GIS applications and data collection techniques, like Remote
Sensing, Photogrammetry and GPS. Finally close future strategies on national geodetic infrastructure that are going to be applied in
Turkey will be pointed out and interpreted.
1. INTRODUCTION
Today, use of Geographical Information System (GIS), Global
Positioning System (GPS) and Remote Sensing are taking very
important role for most of the governmental institutions,
municipalities, private companies and etc. Since, they would
like to monitor changes, illegal constructing activities,
pollution, agricultural activities and etc. in their responsible
region. More over they would like to rapidly update
information on their systems with reliable and accurate data. In
other words, they would like to establish a GIS for meeting
their requirements and would like to use remote sensing and
GPS for rapid data collection. In other way, day by day the
resolution of remote sensing images is extremely increasing.
Therefore the accuracy of coordinates of control points on
images is getting much more important than the past. Since
much reliable and accurate positioning are demanded to shift,
rotate and scale the image coordinate system to national
coordinate system. More over, in most cases there is not only
single coordinate system validity for most countries. Especially
when urban area is concerned, this is much more dramatic in
Turkey. Since there are several existing coordinate systems
such as national (ED50) current, national (ITRF) coming, city-
wide local, zone-wide local and etc. However GIS should have
a fundamental coordinate system that should be transformable
to the other existing coordinate systems to eliminate the
coordinate inconsistency. In effect, this is an easy
mathematical manipulation if the transformation parameters are
valid and if they reflect the character of working area regarding
expected requirements.
2. EXISTING COORDINATE SYSTEMS
As is very well known Turkey is a very old country its history
also past through Ottoman Empire. Therefore several different
types of coordinate systems for regional and country-wide
mapping purposes exist. Moreover information collected from
past to today based on these existing coordinate system. Today
in global level people talk about Geographical Information
Systems (GIS). In general GIS means all geo-based
information collected are gathered within a computer supported
environment and using software all information are queried
regarding relations with each other. Hence the results of query
arc used to make decision. However in order to integrate all
these geo-based information they must all be identified on a
common coordinate system and datum. This means that if
several different coordinate system and datum exist, these must
be convertible each other. Otherwise geo-based information
gathered within a system cannot be integrated with each other.
They might demonstrate messy results that might not be
beneficial.
Therefore if a GIS is concerned whatever data or data collection
technique or system is used the coordinate system and datum
information that data are based on is very important. In that
case everyone who will set up a GIS must have geodetic
background of the data. Moreover one should have excellent
knowledge of existence geodetic infrastructures that data in the
based can correctly be interpreted and integrated with each
other.
Following lines and sections provide detail information about
the geodetic infrastructure of Turkey for the people who would
Internati
like to «
collectic
Fist tecl
systems
of map :
regulati
the tech
regulatit
plans or
based 0
edging |
ground
fitting t
were af
was S
1:5000
the cui
Product
connect
previou
nationa
most €
regulati
to use
produc:
Mercat
only ca
all type
collecti
this an
for all
current
2. m
Nation:
beginn
Nation
chain r
As is
netwo
down
analys
seen t
impor
The d
Datun
geode
Bulga
