Neb Map Service 
1 
:MODnet 
BATHYMETRY "9 meseack 
AR CONTR- 
Seiectlon Leyer 
Data Layer (Points) 
Dana layer Tracks) 
Data Layer (Pobygons 
Data Layer (Polis) 
Data Layer (Tracks) 
Das layer (Pohgons: 
Aue marbie 
Hekam Subbasim 
MSFÜ rEgIOn FERIO. 
KES Ecoreglans. 
Dapar Region 
Towstlines - EMO 
AMasarı death with la. 
BAAR def - EMD.. 
Mean depth multic, 
Rdn bone Cakur - E- 
EMKOOREL BatyftHE 
BEBCO batfıymalıy 
Gele 
DoanSaathiag 
— 
Bm 
— 
HE 
ul 
0 
Oo 
1060 
100 
100 
L 
1 
‚Dal 
Sig. 2: Example of survey coverage. Individual polygons or polylines indicate a specific survey which is associated to standart 
netadata (see text), including a reference to the data originator and/or the data distributor 
arder to overcome this diversity, an effective and 
ıdapted data management system has been de 
signed in accordance with international standards 
and common practice. The full EMODnet Bathym 
etry processing chain, including metadata gen- 
aration and data sampling, is illustrated in Fig,.3. It 
’eads from the top, where post-processed source 
Jata (Le. data that have undergone a full hydro- 
graphic workflow) are described (metadata pro 
duction) and sampled using dedicated software, 
MVetadata are made available for cataloguing (CDI 
and CPRD as introduced earlier). Sampled data are 
made available for validation/quality check and 
zompilation in a regional DTM, prior to the integra- 
ion in the complete DTM and display on the web 
oortal. 
The EMODnet Bathymetry consortium benefits 
GLOBAL WORFLOW 
input of ° “ataset in FMODNFT bathymetry DTM 
MOD net 
> 
. 
MM. adaca 
Creation 
> 
Data 
Creation 
= 
. Data 
/ Conversio: 
Legend 
Dreatiot: 
® Action 
Idantifar 
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ar yaliriatle. 
Dat 
dba? 
Transfe: 
"alien 
a 
Validated metadaf 
2VA1 Slam 
/alidated information 
Un mr 
[Data Transfer > 
wir er VL 
. CDI Data Discovery and 
Access service 
Bathymetry Viewer and 
Web service 
“Mvmetryv port 
fr Sextant CPRD Catalogue A 
service 
ARE 
Cig. 3: Overall post-processed data and associated metadata workflow. including roles an” 
actions of the partners of the project 
from a wide panel of expertise and resources from 
the semi-distributed network of 49 directly con 
tributing organisations. By semi-distributed net- 
work, one understands two main ideas. First, data 
sources are always being held by the originating 
organisation, which can freely decide how they 
can put into effect their national or organisational 
data policy relative to the distribution to end Us- 
ers. Only metadata and the associated viewing/ 
downloading services are being commonly cen- 
tralised. For data participating in the DTM, source 
data are being sampled at the common DTM grid 
"esolution (associated with a commonly agreed 
cell geometry, see below). Second, roles of the 
contributors are distributed amongst data provid- 
ers, regional basin coordinators and DTM/Porta 
ntegrator. While the data providers have direct ac 
cess to the source data, they also have a detailed 
«nowledge of the conditions in which they have 
been acquired and processed. Their role is to pro- 
cess data (hydrographic workflow), prepare the 
mnetadata and down sample the post-processed 
source data. This information is then used by one 
or more of the twelve basin coordinators in order 
to aggregate the data and compose a DTM over 
their area of responsibility (BSH is responsible for 
the North Sea). Through this process, a feedback 
o0p enables a first level of quality analysis. All the 
basin coordinators provide their compilation to 
the DTM/Portal integrator who makes sure they 
all fit together coherently and all convey associ 
ated data attributes (soundings density, main con- 
tributor, minimum and maximum water depth, 
standard deviation per grid cell) and lineage to the 
nNetadata. Through this second check, the quality 
assurance of the DTM product is further ensured. 
Key to all this methodology is standardisatior 
and harmonisation of the methods and tools. 
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