GPS SURVEY OF SLOVENIANNCOASTLINE AND ITS INTEGRATION WITH 
HYDROGRAPHIC DATA 
Igor KARNICNIK, M.Sc. Dalibor RADOVAN 
Geodetic Institute of Slovenia, Jamova 2, Ljubljana, Slovenia, igor.karnicnik@geod-is.si, dalibor.radovan@geod-is.si 
KEY WORDS: Hydrography, GPS, Survey, Spatial data, Integration 
ABSTRACT: 
The aim of hydrography is to ensure safe navigation with aid of modern navigation equipment and nautical charts. Nautical charts 
play crucial role at the mariner's every day's job. The advent of the ships with exceptionally deep draught, the recognition of the 
need to protect the marine environment, the maritime trading and the growing importance of seabed resources, have all served to 
highlight the need for up-to-date hydrographic surveying. With the advent of GPS, the data which may have been adequate a decade 
ago, today have to be recompiled using new survey techniques, collected to a higher degree of accuracy and providing improved 
coverage. Fortunately, GPS technology has enabled us to apply accurate positioning on sea and land. The survey of the coastline and 
coastal objects for navigation has been executed with real-time kinematic GPS method. DGPS corrections have been provided by 
permanent reference station located in the vicinity of the Port of Koper. Production of a nautical chart demands various types of data 
(depths, contour lines, aids to navigation, dangers to navigation, geographical names, land topography, restricted areas and 
navigation routes). Many of them could be in different coordinate systems and are measured with various equipment. Integration of 
such data will be described in the case of nautical chart production. 
1. INTRODUCTION 2. COASTLINE 
More than 80% of international trade in the world is carried by 2.1 The need for a precise coastline 
sea. Maritime commerce is a basic element for a nation's 
economy. The shipping industry needs efficiency and safety. In the past the hydrographic and land surveys were carried out 
Poorly charted areas and lack of information can cause voyages in a different way then today. The equipment was different and 
to be longer than necessary, may prevent the optimum loading less accurate. Acquisition of soundings was done by lead line, 
and unloading of ships and thus increasing costs. today we determine depths by modern ultra sound sonar. The 
determination of ship's position was done in many ways. From 
Modern nautical charts are required for safe navigation through visual methods (measuring angels by optical instruments — 
a country's waters, along coasts and to enter its ports. A lack of sextant or theodolite), electronic methods to today's satellite 
such charts prevents the development of marine trade. It is also positioning methods, GPS. 
very important, that the SOLAS Convention Chapter V 
considers a ship unseaworthy if it does not carry up-to-date The accuracy of such methods was, comparing to the equipment 
charts necessary for the intended voyage. of today, poor. The lack of funds and need for fast and precise 
navigational information resulted in a way, that many 
Slovenia is a member of the International Hydrograpic ~~ hydrographic offices integrated old coast line with newly 
Organization (IHO) since 15. April 2002. This brings certain acquired soundings. This of course reflected in a difference of 
rights and also some responsibilities for Slovenia as a young position of old survey of a coastline and new depths. There is 
maritime country. Although we have only some 45 km of a also the effect of transformations of co-ordinates between old 
coastline, we have to assure safe navigation through our waters. coordinate systems, in which nautical charts used to be and new 
That means hydrographic activities, production and updating of system (nowadays based on ellipsoid of WGS84). There were 
nautical charts and publications, and also survey of a coastline. occasions where new depths "landed" on a coast. 
Slovenia started it's hydrographic activity soon after In order to avoid such a situation, the best way is to survey (or 
independence. First hydrographic survey was finished in 1998 re-survey) a coastline. This is also practical since in years a 
with a co-operation with Navoceano, USA, in 1999, 2000 and coastline changed. The erosion, accumulation by rivers, 
2003 three surveys were done by Slovenia, in 2002 a joint construction of new ports and marinas created a new coastline. 
survey in co-operation of Slovenia, Croatia and Italy was done 
in area of the Bay of Piran. With this we acquired required data 2.2 Definition of a coastline 
for production of our own nautical chats. In 2001 and 2002 we 
surveyed also complete coastline from the border with Italy to 
the border with Croatia. 
There are many definitions of a coastline. The Hydrographic 
dictionary uses the following definition (IHO, 1994): "Coastline 
is the line, where shore and water meet." 
Terminology of coast and shore is rather confused and terms 
shoreline and coastline are generally used as synonymous. 
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