Improving README grammar and adding composites and tristimulus for OLCI. Adding Landsat 5 and 7 content, to prepare for incoming composites.

Author: Monja Šebela

README.md

@@ -131,14 +131,16 @@ Dedicated to supplying data for [Copernicus services](http://www.esa.int/Our_Act
 
 Sentinel-3 is a low Earth-orbit moderate size satellite compatible with small launchers including VEGA and ROCKOT. The main objective of the mission is to measure sea surface topography, sea and land surface temperature, and ocean and land surface color with high accuracy and reliability to support ocean forecasting systems, environmental monitoring and climate monitoring. Ocean and Land Colour Instrument (OLCI) provides a set of 21 bands ranging from the visible to the near infrared light (400 nm < λ< 1 020 nm). The Sentinel-3 provides imagery in 300 m spatial resolution. Sentinel-3 OLCI instrument ensures continuity of the ENVISAT MERIS.
 
+ - [Simple RGB composites](sentinel-3/composites)
+
 #### Enhanced true color scripts
  - [Enhanced true color](sentinel-3/enhanced_true_color)
  - [Enhanced true color-2](sentinel-3/enhanced_true_color-2)
+ - [Tristimulus](Sentinel-3/tristimulus)
 
 #### Remote sensing indices
  - [OTCI](sentinel-3/otci) - Terrestrial chlorophyll index
 
-
 ## <a name="sentinel-5P"></a>Sentinel-5P
 
 Sentinel-5P provides atmospheric measurements, relating to air quality, climate forcing, ozone and UV radiation with high spatio-temporal resolution. Its data is used for monitoring of concentrations of carbon monoxide (CO), nitrogen dioxide (NO2) and ozone (O3) in air as well as for monitoring of UV aerosol index (AER_AI) and different geophysical parameters of clouds (CLOUD). EO Browser serves level 2 geophysical products. The TROPOspheric Monitoring Instrument (TROPOMI) on board of the satellite operates in the ultraviolet to shortwave infrared range with 7 different spectral bands: UV-1 (270-300nm), UV-2 (300-370nm), VIS (370-500nm), NIR-1 (685-710nm), NIR-2 (755-773nm), SWIR-1 (1590-1675nm) and SWIR-3 (2305-2385nm). Its spatial resolution is below 8km for wavelengths above 300nm and below 50km for wavelength below 300nm. It covers almost the whole globe (95 % coverage for latitudes in the interval [-7°, 7°]).
@@ -147,7 +149,8 @@ Sentinel-5P provides atmospheric measurements, relating to air quality, climate
  - [Nitrogen Dioxide tropospheric column](sentinel-5p/nitrogen_dioxide_tropospheric_column)
 
 
-## <a name="landsat-8"></a>Landsat-8
+
+## <a name="landsat-8"></a>Landsat 8
 The Landsat program is the longest running enterprise for acquisition of satellite imagery of Earth, running from 1972. The most recent, [Landsat 8](http://landsat.usgs.gov/landsat8.php){:target="_blank"}, was launched on February 11, 2013. Landsat-8 data has 11 spectral bands with spatial resolutions ranging from 15 to 60 meters. The names of the Landsat-8 bands at your disposal are *B01*, *B02*, *B03*, *B04*, *B05*, *B06*, *B07*, *B08*, *B09*, *B10* and *B11*.
 
 #### Remote sensing indices
@@ -157,6 +160,14 @@ The Landsat program is the longest running enterprise for acquisition of satelli
 #### Other available scripts
   - [Land surface temperature (LST) mapping](landsat-8/land_surface_temperature_mapping)
 
+## <a name="landsat-8"></a>Landsat 5 and 7
+
+Landsat 7 and the retired Landsat 5 orbit's are sun-synchronous, with near-polar orbits, flying at an altitude of 705 km (438 mi). Landsat 5 long outlived its original three-year design life. Developed by NASA and launched in 1984, Landsat 5 has orbited the planet over 150,000 times while transmitting over 2.5 million images of land surface conditions around the world. The Landsat 7 satellite still orbits the the Earth in a sun-synchronous, near-polar orbit, at an altitude of 705 km (438 mi). The satellites are multispectra, providing visible, near infrared, mid infrared and thermal bands. 
+
+For more on Landsat 5, including its available bands, read [here](https://www.usgs.gov/land-resources/nli/landsat/landsat-5?qt-science_support_page_related_con=0#qt-science_support_page_related_con){:target="_blank"} and for Landsat 7, read [here.](https://www.usgs.gov/land-resources/nli/landsat/landsat-7?qt-science_support_page_related_con=0#qt-science_support_page_related_con){:target="_blank"}. 
+
+
+
 
 ## <a name="modis"></a>MODIS
 The Moderate Resolution Imaging Spectroradiometer (MODIS) MCD43A4 version 6 on Sentinel Hub is hosted at Amazon Web Services (AWS). Dataset is updated daily and provides the 500 meter Nadir Bidirectional reflectance distribution function Adjusted Reflectance (NBAR) data of MODIS "land" bands 1-7: *B01*, *B02*, *B03*, *B04*, *B05*, *B06* and *B07*.

sentinel-2/arvi/README.md

@@ -12,7 +12,7 @@
  - [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..
+ARVI is most useful in regions of high atmospheric aerosol content. It uses blue light reflectance measurements to correct for the atmospheric scattering effects, that also influence reflectance of red light.
 
 General formula: 
 
@@ -27,3 +27,4 @@ The ARVI of Rome, Italy. Acquired on 08.10.2017, processed by Sentinel Hub.
 ![ARVI](fig/fig1.png)
 
 
+

sentinel-2/evi/README.md

@@ -13,9 +13,10 @@
 
 ## General description of the script
 
-In areas of dense canopy where the leaf area index (LAI) is high, the NDVI values can be improved by leveraging information in the blue wavelength. Information in this portion of the spectrum can help correct for soil background signals and atmospheric influences.
+In areas of dense canopy cover, where leaf area index (LAI) is high, the blue wavelengths can be used to improve the accuracy of NDVI, as it corrects for soil background signals and atmospheric influences.
+
+Values description: The range of values for EVI is -1 to 1, with healthy vegetation generally around 0.20 to 0.80.
 
-Values description: The range of values for the EVI is -1 to 1, where healthy vegetation generally falls between values of 0.20 to 0.80.
 
 ## Description of representative images
 

sentinel-2/msi/README.md

@@ -15,7 +15,7 @@
 
 The MSI is a reflectance measurement, sensitive to increases in leaf water content.
 
-With the increase of water content of leaves in vegetation canopies increases also the strength of absorption around 1599nm. Absorption at 819nm is used as a reference, since it’s nearly unaffected by changing water content. Applications of the MSI include canopy stress analysis, productivity prediction and modelling, fire hazard condition analysis, and studies of ecosystem physiology. This index is inverted relative to other water vegetation indices; higher values indicate greater water stress and less water content.
+As water content in vegetation canopy leaves increases, the absorbtion at wavelengths around 1599 nm also increases. Absorption at 819nm is used as a reference, since it’s nearly unaffected by changes in water content. Applications of the MSI include canopy stress analysis, productivity prediction and modelling, fire hazard analysis, and studies of ecosystem physiology. The index is inverted relative to the other water vegetation indices; higher values indicate greater water stress and less water content.
 
 Values description: The values of this index range from 0 to more than 3. The common range for green vegetation is 0.4 to 2.
 
@@ -25,4 +25,5 @@ Values description: The values of this index range from 0 to more than 3. The co
 
 The MSI of Rome, Italy. Acquired on 08.10.2017, processed by Sentinel Hub. 
 
-![MSI](fig/fig1.png)
+![MSI](fig/fig1.png)
+

sentinel-2/nbr/README.md

@@ -13,10 +13,11 @@
 
 ## General description of the script
 
-To detect burned areas, the NBR-RAW index is the most appropriate choice. It highlights burned areas in large fire zones greater than 500 acres. Create pre- and post-fire NBR images, subtract the post-fire image from the pre-fire image to create a differenced (or delta) NBR image that indicates burn severity.
+To detect burned areas, the NBR-RAW index is the most appropriate choice. Using bands 8 and 12 it highlights burnt areas in large fire zones greater than 500 acres. To observe burn severity, you may subtract the post-fire NBR image from the pre-fire NBR image.
 
 Values description: Darker pixels indicate burned areas.
 
+
 **NBR = (B08 - B12) / (B08 + B12)**
 
 ## Description of representative images

sentinel-2/ndii/README.md

@@ -11,14 +11,14 @@
  - [EO Browser](https://apps.sentinel-hub.com/eo-browser/?lat=42.5463&lng=11.5961&zoom=11&time=2019-12-10&preset=CUSTOM&datasource=Sentinel-2%20L1C&layers=B01,B02,B03&evalscript=ICAgICAgLy8KLy8gTm9ybWFsaXplZCBEaWZmZXJlbmNlIDgxOS8xNjAwIE5ESUkgKGFiYnJ2LiBORElJKQovLwovLyBHZW5lcmFsIGZvcm11bGE6ICg4MTlubS0xNjAwbm0pLyg4MTlubSsxNjAwbm0pCi8vCi8vIFVSTCBodHRwczovL3d3dy5pbmRleGRhdGFiYXNlLmRlL2RiL3NpLXNpbmdsZS5waHA%2Fc2Vuc29yX2lkPTk2JnJzaW5kZXhfaWQ9MjQyCi8vCgpsZXQgaW5kZXggPSAoQjA4IC0gQjExKSAvIChCMDggKyBCMTEpOwpyZXR1cm5baW5kZXhd){:target="_blank"}
 ## General description of the script
 
-This index uses a normalized difference formulation instead of a simple ratio. It is a reflectance measurement, sensitive to changes in water content of plant canopies. The index values increase with increasing water content. Applications include agricultural crop management, forest canopy monitoring, and stressed vegetation detection.
+This index uses a normalized difference formulation index of wavelengths 819/1600 nm, which corresponds to bands B08 and B11 for Sentinel-2. It is a reflectance measurement, sensitive to changes in water content of plant canopies. The index values increase with increasing water content. Applications of NDII include agricultural crop management, forest canopy monitoring, and stressed vegetation detection.
 
-Values description: The values of this index range from -1 to 1. The common range for green vegetation is between values of 0.02 to 0.6.
+Values description: The values of this index range from -1 to 1. The common range for green vegetation is between the values of 0.02 to 0.6.
 
 **NBR = (B08 - B11) / (B08 + B11)**
 
 ## Description of representative images
 
 NDII, Italy. Acquired on 08.10.2017, processed by Sentinel Hub. 
 
-![NDII](fig/fig1.png)
+![NDII](fig/fig1.png)

sentinel-2/ndvi/README.md

@@ -13,10 +13,13 @@
 
 ## General description
 
+The well known and widely used NDVI is a simple, but effective index for quantifying green vegetation. It normalizes green leaf scattering in Near Infra-red wavelengths with chlorophyll absorption in red wavelengths.
+
+The value range of the NDVI is -1 to 1. Negative values of NDVI (values approaching -1) correspond to water. Values close to zero (-0.1 to 0.1) generally correspond to barren areas of rock, sand, or snow. Low, positive values represent shrub and grassland (approximately 0.2 to 0.4), while high values indicate temperate and tropical rainforests (values approaching 1). It is a good proxy for live green vegetation; see [1] for details.
+
 The normalized difference vegetation index, abbreviated NDVI, is defined as   
 $$NDVI := \mathtt{Index}(B8,B4) = \frac{B8-B4}{B8+B4}.$$   
 
-It is a good proxy for live green vegetation; see [1] for details.
 
 ## Description of representative images
 

sentinel-2/ndwi/README.md

@@ -13,6 +13,8 @@
 
 ## General description of the script
 
+The NDWI is useful for water body mapping, as water bodies strongly absorb light in visible to infrared electromagnetic spectrum. NDWI uses green and near infrared bands to highlight water bodies. It is sensitive to built-up land and can result in over-estimation of water bodies.
+
 Normalized Difference Water Index (NDWI) may refer to one of at least two remote sensing-derived indexes related to liquid water:
 
 One is used to monitor changes in water content of leaves, using near-infrared (NIR) and short-wave infrared (SWIR) wavelengths, proposed by Gao in 1996.
@@ -23,6 +25,8 @@ Another is used to monitor changes related to water content in water bodies, usi
 
 **NDWI = (B03 - B08) / (B03 + B08)**
 
+Values description: Index values greater than 0.5 usually correspond to water bodies. Vegetation usually corresponds to much smaller values and built-up areas to values between zero and 0.2.
+
 ## Description of representative images
 
 NDWI (for water content in leaves) of Rome. Acquired on 8.10.2017.

sentinel-2/sipi1/README.md

@@ -13,12 +13,12 @@
 
 ## General description of the script
 
-The SIPI index maximizes sensitivity to the ratio of bulk carotenoids to chlorophyll while minimizing the impact of the variable canopy structure. It is very useful in areas with high variability in the canopy structure, or leaf area index..
+The SIPI index maximizes sensitivity to the bulk carotenoids to chlorophyll ratio, while minimizing the impact of the variable canopy structure. It is very useful in areas with high variability in the canopy structure, or leaf area index..
 
-Values description: The range of a SIPI is from 0 to 2, where healthy green vegetation is from 0.8 to 1.8.
+Values description: SIPI values range from 0 to 2, where healthy green vegetation ranges from 0.8 to 1.8.
 
 ## Description of representative images
 
 SIPI of Rome. Acquired on 8.10.2017.
 
-![NDVI of Rome](fig/fig1.png)
+![NDVI of Rome](fig/fig1.png)

sentinel-3/composites/README.md

@@ -0,0 +1,43 @@
+# Simple RGB Composites (Sentinel-3)
+
+## True Color
+
+### RGB (8, 6, 4)
+
+True color composite uses visible light bands red (B04), green (B03) and blue (B02) in the corresponding red, green and blue color channels, resulting in a natural colored result, that is a good representation of the Earth as humans would see it naturally.
+
+Custom script: ** return [B08, B06, B04];
+
+![True color sample](fig/fig1.png)
+
+ - [Reference](https://sentinel.esa.int/web/sentinel/user-guides/sentinel-3-olci/overview/heritage)
+ 
+
+## False Color 1
+
+### RGB (17,6,3)
+
+Custom script: ** return [B17, B06, B03];
+
+![False color sample](fig/fig2.png)
+
+## False Color 2
+
+### RGB (17,5,2)
+
+Custom script: ** return [B17, B05, B02];
+
+![False Color 2 sample](fig/fig3.png)
+
+
+
+
+
+
+
+
+
+
+
+
+

sentinel-3/composites/fig/fig1.jpg

@@ -0,0 +1,25 @@
+# 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=19.768&lng=93.233&zoom=9&time=2020-01-27&preset=3_TRISTIMULUS&datasource=Sentinel-3%20OLCI){:target="_blank"}   
+
+## Description
+
+The colours from natural waters differ markedly over the globe, depending on the water composition and illumination conditions. The space-borne “ocean colour” instruments are operational instruments designed to retrieve important water-quality indicators, based on the measurement of water leaving radiance in a limited number (5 to 10) of narrow (≈10 nm) bands. 
+
+The derivation of the true colour of natural waters is based on the calculation of the Tristimulus values that are the three primaries (X, Y, Z) that specify a colour stimulus of the human eye. On how tristimulus is calculated, read [here.](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4634488/){:target="_blank"}
+
+## Description of representative images
+
+Tristimulus water colors at west coast of Myanmat. Acquired on 27.1.2020, processed by Sentinel Hub. 
+
+![Tristimulus of Myanmar](fig/fig1.png)]
+
+
+

sentinel-3/composites/fig/fig1.png

@@ -0,0 +1,8 @@
+// Sentinel-3 OLCI - Tristimulus
+
+var red = Math.log(1.0 + 0.01 * B01 + 0.09 * B02+ 0.35 * B03 + 0.04 * B04 + 0.01 * B05 + 0.59 * B06 + 0.85 * B07 + 0.12 * B08 + 0.07 * B09 + 0.04 * B10);
+var green= Math.log(1.0 + 0.26 * B03 + 0.21 *B04 + 0.50 * B05 + B06 + 0.38 * B07 + 0.04 * B08 + 0.03 * B09 + 0.02 * B10);
+var blue= Math.log(1.0 + 0.07 * B01 + 0.28 * B02 + 1.77 * B03 + 0.47 * B04 + 0.16 * B05);
+
+return [red,green,blue];
+