Mention bias of Mercator map projection, thanks @alicetragedy

Signed-off-by: Jan-Christoph Borchardt <hey@jancborchardt.net>

README.md

@@ -12,6 +12,10 @@
 - **📱 Devices:** Lost your phone? Check the map!
 - **〰 Tracks:** Load GPS tracks or past trips. Recording with [PhoneTrack](https://f-droid.org/en/packages/net.eneiluj.nextcloud.phonetrack/) or [OwnTracks](https://owntracks.org) is planned.
 
+Future plans:
+- **📆 Events on the map:** Know where you need to go next!
+- **🗺 Different projections:** The [Mercator projection](https://en.wikipedia.org/wiki/Mercator_projection) is very biased, as you can see from [The True Size of Africa](http://kai.sub.blue/en/africa.html). Another view like the [Gall-Peters projection](https://en.wikipedia.org/wiki/Gall%E2%80%93Peters_projection) would be a possibility.
+
 
 ## 🏗 Development setup
 

templates/settings/index.php

@@ -10,5 +10,9 @@
         <label for="track-me"><?php p($l->t('Track my position')); ?></label>
         <input type="checkbox" id="display-slider" class="checkbox">
         <label for="display-slider"><?php p($l->t('Display time filter slider')); ?></label>
+        <p>
+            <?php p($l->t('Keep in mind that map projections always distort sizes of countries. The standard Mercator projection is particularly biased. Read more at:')); ?><br>
+            <a href="http://kai.sub.blue/en/africa.html" target="_blank"><?php p($l->t('The True Size of Africa')); ?> ↗</a>
+        </p>
     </div>
 </div>