## // Import boundaries from asset

## var aoi = ee.FeatureCollection('users/juliusadewopo/MzeTargetRegion_alt_dslv2');

## 
## // Set map center to the aoi for making sure we have the correct study area

## Map.centerObject(aoi, 11)

## 
## // Define period of analysis

## var start = '2018-07-01';

## var end = '2018-10-31';

## 
## var season = ee.Filter.date(start,end);

## print(season);


## // Import Sentinel-1 collection

## var sentinel1 =  ee.ImageCollection('COPERNICUS/S1_GRD');

## 
## 
## // Filter Sentinel-1 collection for study area, date ranges and polarization components

## var sCollection =  sentinel1

##                     //filter by aoi and time

##                     .filterBounds(aoi)

##                     .filter(season)

##                     // Filter to get images with VV and VH dual polarization

##                     .filter(ee.Filter.listContains('transmitterReceiverPolarisation', 'VV'))

##                     .filter(ee.Filter.listContains('transmitterReceiverPolarisation', 'VH'))

##                     // Filter to get images collected in interferometric wide swath mode.

##                     .filter(ee.Filter.eq('instrumentMode', 'IW'));

## 
## // Also filter based on the orbit: descending or ascending mode

## var desc = sCollection.filter(ee.Filter.eq('orbitProperties_pass', 'DESCENDING'));

## var asc = sCollection.filter(ee.Filter.eq('orbitProperties_pass', 'ASCENDING'));

## 

## // Inspect number of tiles returned after the search; we will use the one with more tiles

## print("descending tiles ",desc.size());

## print("ascending tiles ",asc.size());

## 
## // Also Inspect one file

## print(asc.first());


## // Create a composite from means at different polarizations and look angles.

## var composite = ee.Image.cat([

##   asc.select('VH').mean(),

##   asc.select('VV').mean(),

##   desc.select('VH').mean()

## ]).focal_median();

## 
## // Display as a composite of polarization and backscattering characteristics.

## Map.addLayer(composite, {min: [-25, -20, -25], max: [0, 10, 0]}, 'composite');


## 
## var collection = ee.ImageCollection(asc.select('VV').merge(desc.select('VV')))

## 
## // Mean

## var mean = collection.reduce(ee.Reducer.mean());

## 
## //alternate: var mean = collection.mean();

## 
## // Median

## var med = collection.reduce(ee.Reducer.median());

## 
## //alternate: var med = collection.median();

## 

## // Standard Deviation

## var sd = collection.reduce(ee.Reducer.stdDev());

## 
## // Percentile

## // Lower values---possibily wet

## var p10 = collection.reduce(ee.Reducer.percentile([10]));

## // Higher values---possibily dry/bright

## var p90 = collection.reduce(ee.Reducer.percentile([90]));

## 

## // compute difference of p90 and p10

## 
## var nd_diff = p90.subtract(p10).focal_mean();

## // Plot the difference layer to use with inspector

## Map.addLayer(nd_diff, {}, 'diff', false);

## 
## // Threshold difference value from the inspector from some known location

## var th = 7; // Selecting this value is tricky;

## 
## var crop_mask = nd_diff.gt(th);

## var crop = crop_mask.updateMask(crop_mask);

## 
## var cropViz = {palette:"yellow"};

## Map.addLayer(crop, cropViz, 'Potential crop areas');

## 
## //Focus on some speific plot

## var point = ee.Geometry.Point([37.340164603171615, -0.720778037819623]);

## Map.centerObject(point, 13)

## 

## 
## var CRS = 'EPSG:4326'; // Only if you want export in specific reference system

## 
## Export.image.toDrive({

##   image: crop,

##   description: 'exporting-crop-to-drive',

##   fileNamePrefix: 'rcmrd_crop',

##   folder: 'GEE_export', // Name of the Google Drive folder

##   scale: 10,

##   region: aoi ,

##   maxPixels: 1e13,

##   crs: CRS

## });

## 

## 
## // Export the image to an Earth Engine asset.

## 
## Export.image.toAsset({

##   image: crop,

##   description: 'exporting-crop-to-Assest',

##   assetId: 'users/anighosh/rcmrd/crop',

##   scale: 10,

##   region: aoi,

##   pyramidingPolicy: {

##     '.default': 'sample',

##   },

##   maxPixels: 1e13

## });

## 
## 

## // add slider to interactively select rice area

## 
## // try Otsu filter to find the threhold

## 
## // Include Sentinel-2 ndvi

## 
## // Show time series plots

##