265
1 INTRODUCTION
Amongtheobjectivessharedbycountrieswithinthe
European common market is the objective of
improving the performance of their multimodal
logistics chains. By 2030, 30% of goods (compared
with2005)transportedbyroadfreightover300kmin
Europe should shift to other transportation modes
such as seaborne; by 2050 thi
s percentage should
increasetomorethan50%,inordertoachieveamore
competitive, sustainable and resource‐efficient
transport system (European Commission, 2011).
Therefore, knowledge on aspects of inter‐port
competition(Wangetal.,2005),particularlybetween
comparableandadjacentportslocatedwithinasingle
gatewayregion(Notteboom,2009,2010)isessentialin
orderforbotheconomicandsustainabledevelopment
reasons.Firstly,forashippinglinertodemandaport
service and the port to supply tha
t service, the
provision of this service will ultimately be resource
demanding for the actors involved. Secondly, ports’
serviceavailabilityandshipsailingroutes and ports
called influence carriers’ operating costs, and ma
y
include both economic, environmental and societal
aspects,forships both atsea andin port.Therefore,
from the perspective of both the shipping liner
companies,portauthoritiesandgovernors,theactual
ship calls among the container ports in a gateway
region need to be ascert
ained. The rationale for this
studyisthatwhenconductingresearchoninter‐port
competition,porteconomictheoryatteststheconcepts
of complements and substitutes (see for example
Wangetal.,2005).
The research question in this study is to which
degree the container ports in the Norwegian Oslo
Fjord are competing with each other in a
ttracting
shippinglinersshipcalls?
Unit of analysis is container feeder ships actual
sailing routes and roundtrips between adjacent
containergatewayportswithintheOsloFjordregion.
Measuring Container Port Complementarity and
Substitutability with Automatic Identification System
(AIS) Data – Studying the Inter-port Relationships in
the Oslo Fjord Multi-port Gateway Region
H.Schøyen&K.Hjelmervik
UniversityCollegeofSoutheastNorway,Borre,Norway
H.Wang&O.L.Osen
NorwegianUniversityofScienceandTechnology,Ålesund,Norway
ABSTRACT:Thispaperconsidersthedegreeofcompetitionamongsmallandmedium‐sizedcontainerports
locatedinamulti‐portgatewayregion.Thelevelofportcompetitionisevaluatedbymeansofananalysisofthe
revealedpreferencesintheport‐callingpatternofcontainerfeedervesselsdeployedontheirva
riouslinks and
routes.Unitofanalysisisfeedervesselsailinglegsandportsstaysat/betweenadjacentcontainerports.Atthese
ports’ terminals, ships are moored and loading and unloading of containers are performed. The vessel
movementdataisprovidedbytheAutomaticIdentificationSystem(AIS).Astudyoftheprincipa
lcontainer
portsintheOsloFjordareaisperformed,measuringtheactualcontainerfeedertrafficduringtheyearof2015.
ItisdemonstratedtowhichextentportsintheOsloFjordregionareactingassubstitutes,andtowhichextent
theyarefunctioningmoreasacomplementtoeachother.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 11
Number 2
June 2017
DOI:10.12716/1001.11.02.08
266
To answer the research question the
complementarityandsubstitutabilityamongadjacent
OsloFjordcontainerportsismeasured.Thedegreeof
substitutabilityfromashippingoperatorʹsstandpoint
is assessed by means of an analysis of revealed
preferences in the Oslo Fjord container port‐calling
patternofshipsdeployedondifferent
traderoutes.
Thecontainershipidentificationandmotiondata
inthisstudyareprovidedbyAIS.AISisatelemetric
system that automatically transmits a ship’s
information to ports and ships in the vicinity. To
obtain reliable AIS results (Harati‐Mokhtari et al.,
2007) we use static and dynamic ship
information
from the AIS data. Static ship information include
staticdatasuchasshipIMOnumberandname,while
dynamic motion‐related information include
information such as GPS positions. AIS
interconnected sensors repeatedly and automatically
updatedynamicinformation.
Thisstudyis‐toourknowledge‐thefirsttostudy
the foreland dimension
of complementarity and
substitutability within a multiport gateway region
withshipmovementdatafromAIS.
Thepaperisorganizedasfollows:Thenextsection
isaliteraturereviewofthepreviousstudiesoninter‐
portcompetitionandthegaugingofcomplementarity
and substitutability among container ports in multi‐
portgateway
regions.Thesubsequentsectionsoutline
themethodologyusedinthe analysis,the dataused
andtheresultsobtained.Theconcludingremarksare
presentedinthefinalsection.
2 LITERATUREREVIEW
There is a vastliterature considering the application
of AIS data to measure ship and port economic
performanceorsafetyof
operations,seeforexample
Nausetal.,2007;NiNietal.,2011;Chenetal.,2016.
Toachieveinsightintothedegreeofportcompetition
in general, and specifically neighbouring ports’
competition, the theory of complementarity and
substitutability among adjacent gateway ports, as
presentedbyNotteboom(2009)willbe
described.The
level of substitutability from a shipping lineʹs
perspectivecanbemeasuredbymeansofananalysis
of ship operators’ revealed preferences in the port
bundling and port‐calling pattern of ships deployed
on different trade routes. Notteboom (2009, p.745)
asserts:
ˈTwoloadcentresareperfectsubstitutes
foraport
user if that user is willing to substitute one load
centreforanotherataconstantrateˈ
ˈTwoloadcentresareperfectcomplementsifthey
are always “consumed” together in fixed
proportionsbyaportuserˈ
Moreover, ˈA high degree of substitutability
between individual load
centres is associated with
fierce competition. In contrast, a high level of
complementarity would create an environment in
whichmutualcoordinationprevails–atleastforthe
container market segment consideredˈ (Notteboom,
2009,p.745).
Next,asweinthispaperinvestigateadjacentports
–or ports in proximity‐ what that means
in our
context needs to be clarified. This is not
straightforward, as there are several dimensions of
proximity; one example of dimensions of port
proximity is geographical proximity (Hall & Jacobs,
2009), which is the spatial distance between actors
andtheiractivities.Anotherexampleofdimensionsof
portproximityis
functionalproximity.Ourtwomain
proximity dimensions, i.e. criteria, when sampling
ports in this study, are: (1) geographical proximity;
the ports are within the same geographical area;
which is the Oslo Fjord region, and (2) service
proximity; that ports provide the service of loading
and unloading containers ship‐to‐shore, performed
witheitherports’quaycranesortheshipsowncranes
(lift‐on lift‐off, i.e. Lo‐Lo). The Oslo Fjord region,
which can be characterised as a multi‐port gateway
region (Notteboom (2010), includes seven container
gateway ports within the Norwegian port trunk‐
network,seeFigure1.AccordingtoBerg
andSchøyen
(2014), these ports are either being owned by
municipalities:Eitherasaninter‐municipalcompany
or as municipal businesses, and therefore ports
compete on conditions similar to any private
enterprise.
Figure1. The principal container ports in the Oslo Fjord
region.CompiledfromBerg&Schøyen(2014).
Figure1showstheportsinthemulti‐portgateway
of the Oslo Fjord region. Drammen and Oslo are in
thenorthernendofthewesternandeasternfjordarm
respectively.MossandBorgarelocatedontheeastern
side of the Oslo Fjord. Kristiansand, Grenland, and
Larvikareonthe
westernside.
Foreland denotes the geographical area a port
serves through networking with other feeder ports
(Bichou,2013),the foreland consideredinthis paper
are the principal container ports in the Oslo Fjord
region, as depicted in Figure 1, the feeder network
betweenthem, and withforeignports,which are
on
EuropeanmainlandandtheUK,seeSection5.
267
3 METHOD
In this section, we first descript the method to
ascertainships’portcalls,thatistodetectwhereand
whenashipismooredtoacontainerquay.Thereafter
we describe the method applied to define and
measure port‐calling patterns of ships linked to the
sampledports.

3.1 ShipmovementandportcalldatafromAIS
TheuniqueshipidentificationidentityknownasIMO
numbersof the ships and ships’movement dataare
basedonAutomaticIdentificationSystem(AIS) data
which were delivered by the Norwegian Costal
Administration,andareusedtomeasureshipsailings
betweenthese
portsandevaluatesomeimplicationon
inter‐portcompetition.
TheAISdata(geographicpositions inlatitude(lat)
andlongitude(long),andtime)wassortedintimeper
shipfollowingHjelmerviketal.(2017).TheUniversal
TransverseMercator (UTM)positionsinzone33were
calculatedfromthe positionsfollowingthe formulas
originally
derivedbyKrüger(1912).Thespeedofship
mattimestepnisestimatedby

22
11
,, ,,
1
nn nn
xm xm ym ym
n
m
nn
mm
UTM UTM UTM UTM
SMG
TT


(1)
where
,,
,
nn
x
mym
UTM UTM is the UTM position of
ship m at time
n
m
T
.“A ship is defined as being
berthedinportattime
n
m
T ifthespeedoftheshipis
equal to zero and its position is inside one of the
geographical boxes associated with the container
terminals’ berth(s). The time span the ship lies
berthed at the terminal is the time from it arrived
untilitlefttheport”Hjelmerviketal.
(2017).
3.2 Measurementofportbundlesforroundtripstoa
gatewayregion
Inter‐port competition can be defined as the
competition between (or among) different ports
(Wang et al., 2005); within the context of the study
reportedinthispaperthediscussionislimitedsolely
tocontainerports.
Theportsincluded
inaroundtripare theportsa
ship visit before leaving the multi‐port gateway
region.Ashipisassumedtoleavethegatewayregion
ifthereisatimespanofmorethan48hoursbetween
twosubsequentberthings.
Reshuffling the order of the port calls or port
swapping
arecommonwaysofhandlingshipdelays
in multi‐port gateway regions, for the Oslo Fjord
regionseeHordnes(2016).Therefore,thesequenceor
logisticalpatterns (Bichou,2013)the portsare called
withinoneroundtriparenottakenintoconsideration.
Single‐port roundtrips arewhen only one port is
called in
the gateway region for one and the same
roundtrip. Multi‐port roundtrips are when two or
more ports are called in the gateway region forone
andthesameroundtrip.
Figure 2 illustrates a multi‐port gateway region
(Notteboom, 2010) with ship roundtrips to foreign
portsoutsidetheregion.
Figure2. Schematic illustration of a multi‐port gateway
region with five ports, and a roundtrip that includes two
ports in the multiport gateway region and two foreign
ports.
4 DATA
The paper studies container Lo‐Lo ship traffic
between the Oslo Fjord ports during year 2015. The
geographical location of these ports’ container
terminals and their nautical approaches were
identifiedfrom digitalcoastal maps providedonline
by the Norwegian Coastal Administration. Seven
container ports are identified and considered,
consisting
ofeleventerminals.Eachofthoseterminals
are eq uipped with container handling cranes and
yard stacking vehicles to load and discharge
ungearedcontainerships(SchøyenandOdeck,2017).
Data on the individual Oslo Fjord port’s annual
containertraffic,measuredinTwentyfeetEquivalent
Unit(TEU),fortheyearof2015,
werecollectedfrom
Statistics Norway. The dataset contains AIS static
data, including IMO number and AIS dynamic data
such as time and ship position coordinates (lat and
long). More than 2.4 million AIS observations from
2347 ships of different types are collected from 1
January 2015 to 31 December 2015.
Using the
geographical position of the container terminal(s)
situatedineachport,combinedwiththeAISdata,97
different container ships were identified as berthing
attheaforementionedsevencontainerports.Table1
depicts the sampled ports’ ship calls and container
traffic.
NotethatmissingAISsignalsandpossibleerrors
when identifying container ship calls and container
trafficflow,mightintroducenoiseinthedataset.The
results should therefore be received with some
caution.
268
Table1. Ship traffic and container flow over the principal
containerportsintheOsloFjordarea.CompiledfromAIS
andStatisticsNorway.
_______________________________________________
Numberofunique Containertraffic
containershipsperport,TEUs
Source:AISSource:
Year2015 <5calls5callsStatisticsNorway
_______________________________________________
Oslo58195466
Drammen41359464
Moss51963107
Borg5845879
Larvik121161807
Grenland14734557
Kristiansand 191151460
_______________________________________________
Total511740
_______________________________________________
Table1showsthatthedefinitivelargeloadcentre
amongtheOsloFjordportsistheportofOslo,witha
container traffic equal to 195466 TEU, whichequals
nearly 38% of the combined Oslo Fjord ports’
containertraffic.
5 RESULTSANDDISCUSSION
Figure 3shows examples of typical container
feeder
pendulum services, illustrating some foreign
container ports, which to the Oslo Fjord ones are
connected.
Figure3. Examples of typical container feeder pendulum
services. Compiled from Schøyen & Bråthen (2015). The
continuouslinesrepresentatypicalfeederservicebetween
the Oslo Fjord ports and ports in Germany, Sweden and
Denmark. The dashed lines represents an example of an
intra‐EuropeanservicebetweenOsloFjordportsand
ports
intheUK,theNetherlands,andDenmark.
Therolesoffeedersinsupplychains–relativeto
the Oslo Fjord context – is explained in Schøyen &
Bråthen (2015). Short sea container shipping in
Europecanbedividedintotwomarketsegments.The
first segment serves pure intra‐European
transportation and is often referred to as short sea
shipping.Thesecondsegment,feederservice,isan
extensionoftheoceanlinermarket.Afeederservice
connectsatleasttwoportsinorderforthecontainers
toberedistributedtoorfromanocean‐serviceinone
of these ports (UNECE, 2001). In this niche, feeders
represent a link
in global hub‐and‐spoke
containerizednetworks.Forfeederservices,flexibility
inroutingandschedulingbetweenportsandbetween
terminalswithinaportareaisimperative.
Totally707roundtripswithtotally1482portcalls
were identified. An initial analysis gives that on
average2.1portswerecalledperroundtrip.
Next, ships
are frequently – and on the same
roundtrip(timelessthan48hours)‐mooredtomore
thanoneberthduringoneportcall;thatmeansthey
are hauled from one terminal to another within the
portarea,orbetweendifferentquaysatoneterminal
withinthe port area. For port
of Drammen, wefind
threeweeklyandregularcontainershipcalls,a closer
investigation shows that Drammen has only one
containershipberth,thereforesometimesshipsgoto
anchoragejustoutsidetheportafterithasunloaded
containers and then returns to the berth for loading
afterthe other shiphas
finishedits operation. If the
anchorage operation andstay has a duration of less
than 48 hours, that will be counted as one port call
withinoneroundtrip.
Figure4.IllustrationofroundtripsthatincludesOsloFjord
container ports. The lines connect ports that a ship visits
duringaroundtrip.
To go in more details about the differences
between port bundling per roundtrip among the
sevenports,Figure4isdeveloped.Thecoloredlines
in Figure 4 show the most common ship roundtrip
patterns between Oslo Fjord container ports. As
pointedoutinSection3,the sequencethattheports
are
called within one roundtrip are not taken into
consideration. The widest lines between ports in
Figure 4 are the most common ship roundtrip, i.e.
portbundle,whicharetheredlinesthatareforming
thetriangleGrenland‐Oslo‐Moss.
Figure4’slabelsonthecircle’srimshowthatthere
were
154 different container ship roundtrips on
269
Drammenand343onOslo.Foreachindividualport,
thecircle’s rimhasacertainarclength,whichdenotes
the combined number of roundtrip to that port. For
the partof on port’s arclength which have no lines
attached, this denotes roundtrips with calls to only
that port and
no other Oslo Fjord port on that
roundtrip;i.e.asingleportroundtrip.
Figure 5 depicts number of container ship
berthingsatthetwoneighbouringportslocatednear
the most dense population areas in the capital of
Norway:OsloandDrammen.
Figure5. Number of berthings at three of the Oslo Fjord
containerquays.
During 2015, the number of berths at Oslo,
Ormsund, was reduced until the container quay
closed down on 1 January 2016. As illustrated in
Figure 5, the other container terminal in Oslo:
Sjursøya, did not increase accordingly. Drammen,
however, experienced an increase, which indicates
that Drammen and Oslo ports arecompetitors.
Oslo
and Drammen ports are located in the end of two
different fjord arms, but have a largely overlapping
foreland and hinterland. Figures 4 and 5 show that
shipoperatorsseldomdecidetocallonbothOsloand
Drammenatthesameroundtrip.Therefore, thesetwo
ports will typically be
perceived as substitutes.
Substitutes are characterized by fierce competition
(Notteboom, 2009), and Figure 4 informs – as an
example, that the ports of Oslo and Drammen were
competitorsinrespectofcontainerbusiness.
Table 2 depicts –per individual port‐ number of
single port calls versus number of multi‐port calls.
Figure
3andTable2showthatformanyroundtrips
tothe OsloFjord region, only oneport iscalled, i.e.
single‐port roundtrip. The column to the right in
Table2showsthatDrammenandKristiansandwere
the port with the highest single‐call ratio, with 42%
and50%respectively,
i.e.they were theports which
faced the highest substitutability and foreland
competition‐measuredinrespectofattractivenessof
shippingcompanies.
Table2.Ratioofnumberofsingle‐portcallsversusnumber
of multi‐port calls for roundtrips on Oslo Fjord container
ports.
_______________________________________________
Portcalls Single‐port Multi‐port
withina callscalls
roundtrip
[No.] [No.][No.]
_______________________________________________
Oslo342 83 (24%) 259 (76%)
Drammen 154 64 (42%) 90 (58%)
Moss258 71 (28%) 187 (72%)
Borg153 22 (14%) 131 (86%)
Larvik223 3 (1%) 220 (99%)
Grenland 138 1 (1%) 137 (99%)
Kristiansand 214 106(50%) 108 (50%)
_______________________________________________
Totalno. 1482 350 (24%) 1132 (76%)
ofportcalls
_______________________________________________
Totalno. 707 350 (50%) 357 (50%)
ofregionalcalls
_______________________________________________
Table3showsthemostcommonportbundlesfor
roundtrips on the Oslo Fjord container ports. The
mostcommonportbundleisthat‐foroneroundtrip‐
either three ports or one port is called. Notably,
roundtripswithtwoportcallsintheOsloFjord, are
relativelyrare.
Table3. The seven most common port bundles for
roundtripsontheOsloFjordcontainerports.
_______________________________________________
PortbundlePortsperRoundtripsLine
roundtripcoloursin
[No.] [No.] Figure4
_______________________________________________
Grenland‐Oslo‐Moss 364Red
Kristiansand‐Larvik‐Oslo 346Blue
Larvik‐Drammen‐Moss 346Green
Larvik‐Oslo‐Borg341Yellow
Larvik‐Drammen‐Moss‐ 428Purple
Borg
Kristiansand‐Grenland‐ 525Light blue
Larvik‐Oslo‐Borg
Oslo‐Moss220Orange
_______________________________________________
Table3showsthatOsloisincludedinfiveofthe
seven most common bundles. Among these five
bundles, three (Grenland‐Oslo‐Moss, Larvik‐Oslo‐
Borg and Kristiansand‐Grenland‐Larvik‐Oslo‐Borg)
areshipscallingportsonbothwestersideandeastern
side of the Oslo fjord (confer Figure 1) and
two are
calling only ports on one side of the fjord (west:
Kristiansand‐Larvik‐Oslo and east: Oslo‐Moss). For
thetwobundleswhereOsloarenotincluded(Larvik‐
Drammen‐Moss and Larvik‐Drammen‐Moss‐Borg),
the ships are calling ports both at the western side
andeasternsideof
theOsloFjord.
6 CONCLUSION
Theresearchquestionofthisstudyistowhichdegree
arethe containerports inthe NorwegianOslo Fjord
competing with each other in attracting shipping
liners ship calls? The container ship calls to seven
neighbouring ports in the Oslo Fjord were studied
with AIS data,
in an effort to investigate degree of
substitutabilityandcomplementaritybetweenthem.
Thetheoreticalcontributionofthispaperisthata
framework for applying AIS data is developed and
270
presentedtoanalyserevealedpreferenceofshipping
liners when performing roundtrips on ports in the
OsloFjordmulti‐portregion.
Half of the feeder ship roundtrips between Oslo
Fjord ports and foreign ports call one single port in
theOsloFjord;fortheotherhalftheycallmulti‐ports
in
theOsloFjord.Notably, formulti‐portcalls,three
port calls are more common than two port calls:
Feederservicesfrequentlyconnectportslocatedatthe
western and eastern side of the Oslo Fjord. It is
demonstratedtowhichextentsomeoftheportsinthe
Oslo Fjord region are
acting as substitutes, and to
which extent some ports functions more as a
complementtothelargestloadcentre:Oslo.
The results presented should be relevant and
useful for shipping companies, port and container
terminal managers and policy makers both on port
foreland development, for example nautical access,
hinterland connections, for
example road planning,
and for researchers within the field of ship routing
andporteconomics.Themethodandresultsprovided
are probably less valuable for each individual port
manager and container terminal operator, as their
shiptrafficareknownforthemintheirowncollected
statistics.
However, the results should
be received with
somecaution,asthereboundtobenoiseinthedata
andthepresentedresults,duetomissingAISsignals
and possible errors when identifying container ship
calls and container traffic flows. Regarding the
former, the AIS data can be considered as fairly
ʺcleanʺ, as they
originated from automatically
generated GPS‐signals and not from human input
intotheAIS‐system, whichfrequentlycontain errors
inthegivencontext.Thus,onefutureareaofpotentia l
studiesistomakeacloserinvestigationonwhatisa
containership–inrespectofshipdesignandfreight
capability
‐andwhatarethecontainertrafficflows(in
TEUs) and commodities transported between the
portsconsidered.Anotherpossiblefutureextensionin
the container port competition and cooperation
contextis to apply differentapproaches to the same
dataset,thustriangulatingthefindingsandexploring
thevalidityoftheapproaches.
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