add chapter 4

public/index.html

@@ -113,7 +113,12 @@ ul.task-list{list-style: none;}
 </li>
         <li class="sidebar-item">
   <div class="sidebar-item-container"> 
-  <a href="./05-mapping_with_r.html" class="sidebar-item-text sidebar-link"><span class="chapter-number">4</span>&nbsp; <span class="chapter-title">Mapping With R</span></a>
+  <a href="./04-raster_data.html" class="sidebar-item-text sidebar-link"><span class="chapter-number">4</span>&nbsp; <span class="chapter-title">Work with Raster Data</span></a>
+  </div>
+</li>
+        <li class="sidebar-item">
+  <div class="sidebar-item-container"> 
+  <a href="./05-mapping_with_r.html" class="sidebar-item-text sidebar-link"><span class="chapter-number">5</span>&nbsp; <span class="chapter-title">Mapping With R</span></a>
   </div>
 </li>
         <li class="sidebar-item">

references.bib

@@ -331,3 +331,43 @@ Library},
 	date = {2020},
 	url = {https://CRAN.R-project.org/package=cartogram}
 }
+
+@misc{MmadelinSIGR,
+  author = {Malika Madelin},
+  title = {Analyse d’images raster (et télédétection)},
+  howpublished = {\url{https://mmadelin.github.io/sigr2021/SIGR2021_raster_MM.html}},
+  year = {2021},
+  note = {Accessed: {2021–01-03}}
+}
+
+@misc{JNowosadSIGR,
+  author = {Jakub Nowosad},
+  title = {Image processing and all things raster},
+  howpublished = {\url{https://nowosad.github.io/SIGR2021/workshop2/workshop2.html}},
+  year = {2021},
+  note = {Accessed: {2021–01-03}}
+}
+
+@misc{RasterCheatSheet,
+  author = {Etienne B. Racine},
+  title = {The Visual Raster Cheat Sheet},
+  howpublished = {\url{https://rpubs.com/etiennebr/visualraster}},
+  year = {2016},
+  note = {Accessed: {2021–01-03}}
+}
+
+@misc{XingongLi2009,
+  author = {Xingong Li},
+  title = {Map algebra and beyond : 1. Map algebra for scalar fields},
+  howpublished = {\url{https://slideplayer.com/slide/5822638/}},
+  year = {2009},
+  note = {Accessed: {2021–01-03}}
+}
+
+@misc{JMennis2015,
+  author = {Jeremy Mennis},
+  title = {Fundamentals of GIS : raster operations},
+  howpublished = {\url{https://cupdf.com/document/gus-0262-fundamentals-of-gis-lecture-presentation-7-raster-operations-jeremy.html}},
+  year = {2015},
+  note = {Accessed: {2021–01-03}}
+}
\ No newline at end of file