working with SAR

Simple assignment to use SAR.

1. Importing the Data.

Step 1: Go to the Google Earth Engine.

Step 2: Import the Sentinel-1 image collection and call it SAR.

Step 3: Add a marker at Bangkok and call the marker roi.

s1assignment1.jpg

Step 4: add the code below to the script.

// filter on location
var mySAR = SAR.filterBounds(roi)

// print the image collection
print(mySAR)

Question 1: How many images are there in the image collection.

Question 2: How many bands are there in each image, what do they represent?

2. Displaying Data

Step 5: Use the previous script and add the code below.

// imageCollection to list
var mylist= mySAR.toList(500)

// get the angle of first image
var myAngle = ee.Image(mylist.get(1)).select("angle")

Map.addLayer(myAngle)

Step 6: use the inspector to check the angles.

inspector.jpg

Step 7: remove the lines of step 5 and add the code below. Fill in the range of angles at the ??.

// add vizualization parameters
var vizAngle = {min:??, max:??, palette:['FFFFFF,000000']};

// imageCollection to list
var mylist= mySAR.toList(500)

// get the angle of first image
var myAngle = ee.Image(mylist.get(1)).select("angle")

// add the layer
Map.addLayer(myAngle,vizAngle,"angle")

Step 8:Remove the code again and inspect the VV layer using the code below.

 // add vizualization parameters
var vizVV = {min:??, max:??, palette:['FFFFFF,000000']};

// imageCollection to list
var mylist= mySAR.toList(500)

// get the angle of first image
var myVV = ee.Image(mylist.get(1)).select("VV")

Map.addLayer(myVV,vizVV,"VV")

Step 9: Remove the code again and inspect the VV layer using the code below.

 // add vizualization parameters
var vizVV = {min:??, max:??, palette:['FFFFFF,000000']};

// imageCollection to list
var mylist= mySAR.toList(500)

// get the angle of first image
var myVV = ee.Image(mylist.get(1)).select("VV")

Map.addLayer(myVV,vizVV,"VV")

Step 9: Remove the code again and inspect the VV layer using the code below.

// Also add the VH layer.
var vizVH = {min:??, max:??, palette:['FFFFFF,000000']};

// imageCollection to list
var mylist= mySAR.toList(500)

// get the angle of first image
var myVH = ee.Image(mylist.get(1)).select("VH")

Map.addLayer(myVH,vizVH,"VH")

Step 10: Add another image to the map.

Hint: change the number in the get(number).

Step 11: Find this the image below in the image collection and display it.

S1A_IW_GRDH_1SSV_20160714T112841_20160714T112906_012144_012D19_1856

Question 3: What problems you encounter?

3. Identify water

Step 12: Use the code below to identify water. You need to fill in the thresholds by yourself.


var mySAR = SAR.filterBounds(roi)

print(mySAR)

// add vizualization parameters
var vizWater = {min:0, max:1, palette:['40a4df']};

// imageCollection to list
var mylist= mySAR.toList(500);

var myVV = ee.Image(mylist.get(1)).select("VV");

// fill out a value here:
var value = ??;

// water is less than this value
var water1 = myVV.lt(value);
var water1 = water1.updateMask(water1);

// Add to map
Map.addLayer(water1,vizWater,"water VV");

// get the angle of first image
var myVH = ee.Image(mylist.get(1)).select("VH")

var value = ??;

// water is less than this value
var water2 = myVH.lt(value);
var water2 = water2.updateMask(water2);

Map.addLayer(water2,vizWater,"water VH");

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