<slide>
<title>Let's imagine a simple index</title>

<table>
<tr><th>_City_</th><th>Longitude</th><th>Latitude</th></tr>
<tr><td>Aabenraa</td><td>55.04434</td><td>9.41741</td></tr>
<tr><td>Aachen</td><td>50.77664</td><td>6.08342</td></tr>
<tr><td>...</td><td>...</td><td>...</td></tr>
<tr><td>London</td><td>51.50853</td><td>-0.12574</td></tr>
<tr><td>Londonderry County Borough</td><td>54.99721</td><td>-7.30917</td></tr>
<tr><td>Londrina</td><td>-23.31028</td><td>-51.16278</td></tr>
<tr><td>...</td><td>...</td><td>...</td></tr>
<tr><td>Zwijndrecht</td><td>51.8175</td><td>4.63333</td></tr>
<tr><td>Zwolle</td><td>52.5125</td><td>6.09444</td></tr>
<tr><td>Żyrardów</td><td>52.0488</td><td>20.44599</td></tr>
<tr><td>Zyryanovsk</td><td>49.72654</td><td>84.27318</td></tr>
<tr><td>Żywiec</td><td>49.68529</td><td>19.19243</td></tr>
</table>
</slide>
