Database Reference
In-Depth Information
rdf:type mm:Pub ;
7 mm:hasPlaceName “The Isis Tavern” ;
8 postcodes:hasAddress <
http://data.mereamail.gov.me/12345
>
9 foaf:based_near <
http://sws.geonames.org/7290621/
>
.
When the object of the triple is dereferenced, the third-party server provides all
the information about that remote resource. That resource in the other dataset will
be described by many other triples, which may in turn reference resources in even
farther-flung datasets. This is the way in which the whole Web of data is linked, and
by following these links (known as the “follow-your-nose” approach), a user can
browse or a spider can crawl through the Web of Linked Data.
8.4.6 e
ncoding
i
incoMing
l
inkS
If Merea Maps has identified links outgoing from its dataset, the inverse links may
well also be valid, and Merea Maps can include these in their dataset, even though
the subjects of the triples belong to the third-party dataset. This is particularly useful
if the third-party dataset is one of the hubs in the Linked Data Cloud of Figure 2.1, as
it is unlikely that the owners of the popular hub data will be able to create links out
to all possible datasets that are relevant to them. Building on the previous example
from Section 8.4.5, as well as encoding the outgoing links saying that the Isis Tavern
has address
postcodes:12345
and is based near
geonames:7290621
, we can
also add in that
postcodes:12345 isAddressOf
The Isis Tavern (line 6) and
geonames:7290621
is
based _ near
The Isis Tavern (line 7).
1 @prefix rdf: <
http://www.w3.org/1999/02/22-rdf-syntax-ns#
>.
2 @prefix foaf: <
http://xmlns.com/foaf/0.1/
>.
3 @prefix mm: <
http://mereamaps.gov.me/placesOfInterest/
>
.
4 @prefix postcodes: <
http://mereamail.gov.me/addresses/
>.
5
6 <
http://data.mereamail.gov.me/12345
> postcodes:isAddressOf
7 <
http://sws.geonames.org/7290621/
>
foaf:based_near
Note that although we have used
foaf:based _ near
to demonstrate how
external links can work, this example is a little contrived; it is not usual to state that
the town
geonames:7290621
is near the Isis Tavern pub. One would normally
only consider the pub to be near the town unless the pub was exceptionally famous.
8.5 LINK DESIGN PROCESS
As we have already mentioned, since search algorithms operate on the principle of
assigning popularity to a Web page (or Linked Data node) based on the number of incom-
ing links weighted by the linking pages' or nodes' own popularity, it is very important
to link one's datasets to the rest of the Linked Data Web to increase discoverability.
