figure text and refs
authorGuus Schreiber <>
Sun, 16 Feb 2014 18:35:27 +0100
changeset 1915 a81d4f8e99ab
parent 1914 c1537d64872d
child 1916 60fb6507cb48
figure text and refs
RDFa example annotated
--- a/rdf-primer/index.html	Sun Feb 16 01:40:29 2014 +0100
+++ b/rdf-primer/index.html	Sun Feb 16 18:35:27 2014 +0100
@@ -283,10 +283,10 @@
     <strong>graph</strong>. Graphs consists 
     of nodes and arcs. The subjects and
     objects of the triples make up the nodes in the graph; the
-    predicates form the arcs. <a href="#fig-example-graph">Fig. 1</a>
+    predicates form the arcs. <a href="#fig1">Fig.&nbsp;1</a>
     shows the graph resulting from the sample triples.</p> 
-    <figure id="fig-example-graph">
+    <figure id="fig1">
       <img class="graph" src="example-graph.jpg"
                 alt="Informal graphs of the sample triples">
       <figcaption>Informal graph of the sample triples</figcaption>
@@ -418,10 +418,11 @@
       <p class="issue">Fine-tune diagram</p>
-    <figure id="fig-example-blank-node">
+    <figure id="fig2">
       <img class="graph" src="example-blank-node.jpg" 
-                alt="Blank node example">
-      <figcaption>Informal blank node example</figcaption>
+                alt="Blank node example: cypress tree">
+      <figcaption>Informal blank node example: the background of the Mona Lisa depicts
+        an unnamed resource that belongs to the class of cypress trees.</figcaption>
@@ -494,14 +495,14 @@
       in the intended way. Possible semantics of datasets are described in a separate note
       [[RDF11-DATASETS]]. </p> 
-    <figure id="fig-abstract-graph-multiple">
+    <figure id="fig3">
       <img class="graph" src="example-multiple-graphs.jpg" 
                 alt="Informal graph of the sample dataset">
       <figcaption>Informal graph of the sample dataset</figcaption>
       <p><a href="#subsection-trig">Sec. 5.2</a> provides an example
-    of concrete syntax for this example.</p>
+    of concrete syntax for the graph in <a href="#fig3">Fig.&nbsp;3</a>.</p>
@@ -764,14 +765,12 @@
 <p>The figure below shows the triples resulting from this example.</p>
-    <figure id="fig-abstract-graph-single">
+    <figure id="fig4">
       <img class="graph" src="example-graph-iris.jpg" 
                 alt="Graph of the sample triples">
       <figcaption>Graph of the Turtle example</figcaption>
-<p class="issue">TODO: fine-tune figure details, such as literal values</p>
 <p>In case of language-tagged strings the tag
 appears directly after the string, separated by a <code>@</code>
 symbol, e.g. <code>"La Joconde"@fr</code> (the French name of the Mona
@@ -866,7 +865,7 @@
     <p>The figure below shows the triples resulting from this example.</p>
-    <figure id="fig-abstract-graph-multiple-iris">
+    <figure id="fig5">
       <img class="graph" src="example-multiple-graphs-iris.jpg" 
                 alt="Triples resulting from the TriG example">
       <figcaption>Triples resulting from the TriG example</figcaption>
@@ -883,9 +882,9 @@
     application and/or usage needs. The examples given for each of
     these syntaxes correspond to the same graph (i.e., the same set of
     triples) as the Turtle example (in the case of a single graph, see <a
-    href="#fig-abstract-graph-single">Fig. 2</a>) or the TriG example
+    href="#fig4">Fig.&nbsp;4</a>) or the TriG example
     (in the case of multiple graphs, see <a
-    href="#fig-abstract-graph-multiple">Fig. 3</a>). </p>
+    href="#fig5">Fig.&nbsp;5</a>). </p>
@@ -1044,9 +1043,6 @@
     <h2>RDF Data</h2>
-<p class="issue">Check best place to reference as Linked Data entry
-    point</p>
     <p>RDF allows you to combine triples from any source into a graph
     and process it as legal RDF. A large amount of RDF data is
     available as part of the Linked 
@@ -1078,7 +1074,7 @@
     <p>A list of datasets available within the Linked Data cloud is maintained at
-    <a href=""></a>.</p>
+    <a href=""></a>.</p>
     <P>A number of vocabulary terms have become popular for
     recording links between RDF data sources. An example is the
@@ -1136,27 +1132,102 @@
 <section id="section-other-syntaxes" class="appendix">
-   <h2>Examples of RDF syntaxes</h2>
+<h2>Examples of RDF syntaxes</h2>
 <p>In <a href="#section-graph-syntax">Sec. 5</a> the
 different concrete syntaxes of RDF are briefly described. Examples are
 given only of the Turtle and TriG syntax. This appendix lists
 corresponding examples for the other syntaxes listed. The
-single-graph examples encode the same graph as the <a
-   href="#turtle-example">Turtle 
-example</a>; the mutiple-graphs examples encode the same graph as the <a href="#trig-example">Trig
-example</a>. </p>
+single-graph examples encode the same graph as in
+<a href="#fig4">Fig.&nbsp;4</a>;
+the mutiple-graphs examples encode the same graph as in
+<a href="#fig5">Fig.&nbsp;5</a>. </p>
-      <p class="issue">
-    We should consider annotating the examples in this
-    appendix, thus providing a mini-primer for each syntax. </p>
+<section id="subsection-rdfa"> 
-      <section id="subsection-rdfa">
-      <h3>RDFa</h3>
+<p>RDFa [[RDFA-PRIMER]] is an RDF syntax for encoding RDF
+triples in an HTML document. The HTML example below encodes the
+RDF graph depicted in <a href="#fig4">Fig.&nbsp;4</a>:</p>
+<pre class="example" id="rdfa-example">
+01    &lt;div about="" typeof=""&gt;
+02      &lt;p&gt;
+03        Bob knows &lt;a rel="" href=""&gt;Alice&lt;/a&gt;
+04        and was born on the
+05        &lt;span property="" datatype=""&gt;1990-07-04&lt;/span&gt;.
+06      &lt;/p&gt;
+07      &lt;p&gt;
+08        Bob is interested in &lt;a rel="" href=""&gt;the Mona Lisa&lt;/a&gt;.
+09      &lt;/p&gt;
+10    &lt;/div&gt;
+11    &lt;div about=""&gt;
+12      &lt;p&gt;
+13        The &lt;span property=""&gt;Mona Lisa&lt;/span&gt;
+14        was painted by
+15        &lt;a rel="" href=""&gt;Leonardo da Vinci&lt;/a&gt;
+16        and is the subject of the video
+17        &lt;a rev="" href=""&gt;'La Joconde à Washington'&lt;/a&gt;.
+18      &lt;/p&gt;
+19    &lt;/div&gt;
+      </pre>
-      <p>Single-graph example:</p>
+<p>RDFa introduces a number special attributes that enable the
+specification of triples within HTML. For example, the <code>div</code> elements 
+in lines 1 and 11 have an <code>about</code> 
+attribute, specifying the IRI about which RDF statements can be made within this
+block. In line 3 we see a <code>rel</code> ("relation") attribute that an RDFa
+-aware processor should interpret as an RDF property IRI. The
+<code>href</code> attribute value is the object of the triple. Th
+result is the triple: <p>
+<p class="example">
+&lt;; &lt;; &lt;; .
+<p>The <code>rel</code> is used in cases where the object is an
+IRI. Two more examples are found in lines 8 and 15. If the object of
+the triple is a literal, then RDFa uses the
+<code>property</code> attribute to specify the RDF property IRI. Lines
+5 and 13 contain examples of such triples. A <code>datatype</code>
+attribute is used to indicate the datatype of the literal (line 5). If
+no datatype or language tag is specified the literal is assumed to
+have the datatype <code>xsd:string</code> (line 13). </p>
+<p>Two more RDFa attributes appear in the example. The
+<code>typeof</code> attribute in line 1 is similar to the Turtle
+shorthand <code>a</code>: it signals the RDF class to which the IRI
+belongs. The <code>rev</code> ("reverse") attribute in line 17 signals
+that the triple specified should be interpreted in the reverse
+order: the "about" IRI is the object of the triple; the "href"
+attribute specifies the subject. </p>
+<p>The RDFa Primer provides detailed information about RDFa [[RDFA-PRIMER]]. Below shows the HTML rendered from the example:</p>
+<div about="" typeof="">
+    <p>
+      Bob knows <a rel="" href="">Alice</a>
+      and was born on the
+      <span property="" datatype="">1990-07-04</span>.
+    </p>
+    <p>
+      Bob is interested in <a rel="" href="">the Mona Lisa</a>.
+    </p>
+  </div>
+  <div about="">
+    <p>
+      The <span property="">Mona Lisa</span>
+      was painted by
+      <a rel="" href="">Leonardo da Vinci</a>
+      and is the subject of the video
+      <a rev="" href="">'La Joconde à Washington'</a>.
+    </p>
+  </div>
+<!--      <p>Single-graph example:</p>
       <pre class="example" id="rdfa-example">
 01    &lt;div prefix="
 02      rdf:
@@ -1179,6 +1250,8 @@
 19      &lt;/div&gt;
 20    &lt;/div&gt;