Adding S3 OTCI index

Author: MonjaSebela

README.md

@@ -120,6 +120,9 @@ Sentinel-3 is a low Earth-orbit moderate size satellite compatible with small la
 #### Enhanced true color scripts
  - [Enhanced true color](sentinel-3/enhanced_true_color)
  - [Enhanced true color-2](sentinel-3/enhanced_true_color-2)
+ 
+#### Remote sensing indices
+ - [OTCI](sentinel-3/otci) - Terrestrial chlorophyll index
 
 
 ## <a name="sentinel-5P"></a>Sentinel-5P

sentinel-3/otci/README.md

@@ -0,0 +1,28 @@
+# OTCI - OLCI terrestrial chlorophyll index 
+<a href="#" id='togglescript'>Show</a> script or [download](script.js){:target="_blank"} it.
+<div id='script_view' style="display:none">
+{% highlight javascript %}
+      {% include_relative script.js %}
+{% endhighlight %}
+</div>
+
+## Evaluate and visualize
+ - [EO Browser](https://apps.sentinel-hub.com/eo-browser/?lat=44.868&lng=11.415&zoom=7&time=2019-06-30&preset=2_OTCI&datasource=Sentinel-3%20OLCI){:target="_blank"}   
+
+## Description
+OTCI, the Terrestrial Chlorophyll Index, can be used to assess chlorophyll content over land to monitor vegetation condition and health. 
+It is produced globally at 300m spatial resolution from OLCI data on the Sentinel 3 mission. 
+The theoretical basis document on OTCI is available [here.](https://sentinel.esa.int/documents/247904/349589/OLCI_L2_ATBD_OLCI_Terrestrial_Chlorophyll_Index.pdf){:target="_blank"}. 
+
+Blue colors display extremely low OTCI values. They usually signify water, sand or snow. 
+Extremely high values, displayed with white, usually suggest the absence of chlorophyll as well. They generally represent either bare ground, rock or clouds. 
+The chlorophyll values in between range from red (low chlorophyll values) to dark green (high chlorophyll values) and can be used to determine vegetation health. 
+
+## Description of representative images
+
+OTCI in Europe, acquired on 30.6.2019. 
+![OTCI in Europe](fig/fig1.jpg)
+
+## Contributors:
+Monja Sebela 
+

sentinel-3/otci/fig/fig1.jpg

@@ -0,0 +1,15 @@
+// Sentinel-3 OTCI - OLCI terrestrial chlorophyll index
+var OTCI = (B12 - B11) / (B11 - B10);
+return colorBlend   
+    (OTCI,	            
+        [ 0, 1, 1.8, 2.5, 4, 4.5, 5], 
+        [     
+            [0, 0, 0.5],
+            [0, 0.3, 0.8],
+            [1, 0.2, 0.2],
+            [1, 0.9, 0],
+            [0, 0.8, 0.1],
+            [0, 0.6,0.2],
+            [1, 1, 1],
+      ]);
+