Adding cloudless mosaic README file and ARVI img

Author: Monja Šebela

README.md

@@ -62,7 +62,7 @@ Dedicated to supplying data for [Copernicus services](http://www.esa.int/Our_Act
  - [MSI](sentinel-2/msi) - moisture index
  - [NDMI](sentinel-2/ndmi) - normalized difference moisture index
  - [NDWI](sentinel-2/ndwi) - normalized difference water index
- - [NDMI_stress](sentinel-2/ndmi_special) - normalized difference moisture index for crop moisture stress
+ - [NDMI STRESS](sentinel-2/ndmi_special) - normalized difference moisture index for crop moisture stress
  - [NBR](sentinel-2/nbr) - normalized burn ratio  
  - [NDII](sentinel-2/ndii) - normalized difference 819/1600 NDII
  - [NDCI](sentinel-2/ndci) - normalized difference chlorophyll index
@@ -83,6 +83,7 @@ Dedicated to supplying data for [Copernicus services](http://www.esa.int/Our_Act
 #### Cloud detection algorithms
  - [Cohen-Braaten-Yang cloud detection](sentinel-2/cby_cloud_detection/)
  - [Hollstein Clouds, Cirrus, Snow, Shadow, Water and Clear Sky Pixels detection](sentinel-2/hollstein)
+ - [Cloudless Mosaic](sentinel-2/cloudless_mosaic)
 
 #### Snow and glaciers algorithms
  - [Snow classifier](sentinel-2/snow_classifier/)

sentinel-2/arvi/README.md

@@ -1,4 +1,4 @@
-# ARVI
+# Atmospherically Resistant Vegetation Index (ARVI)
 
 <a href="#" id='togglescript'>Show</a> script or [download](script.js){:target="_blank"} it.
 <div id='script_view' style="display:none">
@@ -8,11 +8,22 @@
 </div>
 
 ## Evaluate and visualize
- - [Sentinel Playground](https://apps.sentinel-hub.com/sentinel-playground/?source=S2&lat=43.514198796857976&lng=16.601028442382812&zoom=11&evalscripturl=https://raw.githubusercontent.com/sentinel-hub/custom-scripts/master/sentinel-2/arvi/script.js){:target="_blank"}    
- - [EO Browser](http://apps.sentinel-hub.com/eo-browser/#lat=41.9&lng=12.5&zoom=10&datasource=Sentinel-2%20L1C&time=2017-10-08&preset=CUSTOM&layers=B01,B02,B03&evalscripturl=https://raw.githubusercontent.com/sentinel-hub/customScripts/master/sentinel-2/arvi/script.js){:target="_blank"}   
-
+ - [Sentinel Playground](https://apps.sentinel-hub.com/sentinel-playground/?source=S2&lat=42.190118425644556&lng=11.9970703125&zoom=11&preset=CUSTOM&layers=B01,B02,B03&maxcc=6&gain=1.0&gamma=1.0&time=2018-05-01%7C2018-11-07&atmFilter=&showDates=false&evalscript=Ly8KLy8gQXRtb3NwaGVyaWNhbGx5IFJlc2lzdGFudCBWZWdldGF0aW9uIEluZGV4ICAgKGFiYnJ2LiBBUlZJKQovLwovLyBHZW5lcmFsIGZvcm11bGE6IChOSVIgLSBSRUQgLSB5ICogKFJFRCAtIEJMVUUpKS8gKE5JUiArIFJFRCAtIHkqKFJFRC1CTFVFKSkKLy8KLy8gVVJMIGh0dHBzOi8vd3d3LmluZGV4ZGF0YWJhc2UuZGUvZGIvc2ktc2luZ2xlLnBocD9zZW5zb3JfaWQ9OTYmcnNpbmRleF9pZD00Ci8vCgovLyBJbml0aWFsaXplIHBhcmFtZXRlcnMKbGV0IHkgPSAwLjEwNjsKbGV0IGluZGV4ID0gKEIwOSAtIEIwNCAtIHkgKiAoQjA0IC0gQjAyKSkgLyAoQjA5ICsgQjA0IC0geSAqIChCMDQgLSBCMDIpKTsKCnJldHVybltpbmRleF07){:target="_blank"} 
+ - [EO Browser](https://apps.sentinel-hub.com/eo-browser/?lat=42.3641&lng=12.1880&zoom=10&time=2017-10-08&preset=CUSTOM&datasource=Sentinel-2%20L1C&layers=B01,B02,B03&evalscript=Ly8KLy8gQXRtb3NwaGVyaWNhbGx5IFJlc2lzdGFudCBWZWdldGF0aW9uIEluZGV4ICAgKGFiYnJ2LiBBUlZJKQovLwovLyBHZW5lcmFsIGZvcm11bGE6IChOSVIgLSBSRUQgLSB5ICogKFJFRCAtIEJMVUUpKS8gKE5JUiArIFJFRCAtIHkqKFJFRC1CTFVFKSkKLy8KLy8gVVJMIGh0dHBzOi8vd3d3LmluZGV4ZGF0YWJhc2UuZGUvZGIvc2ktc2luZ2xlLnBocD9zZW5zb3JfaWQ9OTYmcnNpbmRleF9pZD00Ci8vCgovLyBJbml0aWFsaXplIHBhcmFtZXRlcnMKbGV0IHkgPSAwLjEwNjsKbGV0IGluZGV4ID0gKEIwOSAtIEIwNCAtIHkgKiAoQjA0IC0gQjAyKSkgLyAoQjA5ICsgQjA0IC0geSAqIChCMDQgLSBCMDIpKTsKCnJldHVybltpbmRleF07){:target="_blank"}
 ## General description of the script
 
 The ARVI is most useful in regions of high atmospheric aerosol content. It works by using reflectance measurements in the blue wavelengths to correct for atmospheric scattering effects that register in the red reflectance spectrum..
 
+General formula: 
+
+**(NIR - RED - y * (RED - BLUE))/ (NIR + RED - y*(RED-BLUE))**
+
 Values description: The range for an ARVI is -1 to 1 where green vegetation generally falls between values of 0.20 to 0.80.
+
+## Description of representative images
+
+The ARVI of Rome, Italy. Acquired on 08.10.2017, processed by Sentinel Hub. 
+
+![ARVI](fig/fig1.png)
+
+

sentinel-2/arvi/fig/fig1.png

@@ -8,28 +8,6 @@
 
 // Initialize parameters
 let y = 0.106;
-
 let index = (B09 - B04 - y * (B04 - B02)) / (B09 + B04 - y * (B04 - B02));
-let min = -2.4;
-let max = 0.92;
-let zero = 0.0;
-
-// colorBlend will return a color when the index is between min and max and white when it is less than min.
-// To see black when it is more than max, uncomment the last line of colorBlend.
-// The min/max values were computed automatically and may be poorly specified, feel free to change them to tweak the displayed range.
-// This index crosses zero, so a diverging color map is used. To tweak the value of the break in the color map, change the variable 'zero'.
-
-let underflow_color = [1, 1, 1];
-let low_color = [208/255, 88/255, 126/255];
-let high_color = [241/255, 234/255, 200/255];
-let zero_color = [0, 147/255, 146/255];
-let overflow_color = [0, 0, 0];
 
-return colorBlend(index, [min, min, zero, max],
-[
-	underflow_color,
-	low_color,
-	zero_color, // divergent step at zero
-	high_color,
-	//overflow_color // uncomment to see overflows
-]);
+return[index];

sentinel-2/arvi/script.js

@@ -0,0 +1,25 @@
+# Cloudless mosaic
+
+<a href="#" id='togglescript'>Show</a> script1 or [download](L2A-first_quartille.js){:target="_blank"} it.
+<div id='script_view' style="display:none">
+{% highlight javascript %}
+      {% include_relative L2A-first_quartille.js %}
+{% endhighlight %}
+<a href="#" id='togglescript'>Show</a> script2 or [download](L2A-first_quartile_4bands_V2.js){:target="_blank"} it.
+<div id='script_view' style="display:none">
+{% highlight javascript %}
+      {% include_relative L2A-first_quartile_4bands_V2.js %}
+{% endhighlight %}
+</div>
+
+## General description of the script
+
+The Cloudless mosaic script works on Sentinel-2 L2A data and requires scene classification (SCL) band. 
+It takes one year of data, which is quite compute and time intensive, which is why it is recommended to run it on small area (e.g. 256x256 px).
+An example of the results is New Zealand's cloudless mosaic, available here: https://data.linz.govt.nz/layer/93652-nz-10m-satellite-imagery-2017/
+
+For the output value for each pixel it uses the first quartile value of valid values, each band separately. If there are none it uses invalid values instead. 
+When using SCL its very important to use nearest neighbor resampling with a resolution of about 20m/px or more. 
+
+The script is available in custom script Version-1 and Version-2.
+