Tutorial 3: Mapping Deforestation in South Andaman Island Using Vyom
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Tutorial by

**Sourabh Motiani¹**, **Utpal Singh²**, **Satyam Pratap Singh²** 

¹ Department of Earth Sciences, Indian Institute of Technology Roorkee

² School of Geosciences, University of Sydney 
 

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This tutorial demonstrates how to **map deforestation** in the **South Andaman region** using **Kalpa**. We will use the **vyom plugin** to calculate the **Normalized Difference Vegetation Index (NDVI)** from satellite data.

Workflow
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Step 1: Create a Bounding Box
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Start by creating a bounding box of the region.

1. Navigate to **Tools → Vector → Bounding Box**.  

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2. Set the X and Y range for the South Andaman region.

Step 2: Download Satellite Data and Calculate NDVI Using Vyom
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1. Navigate to **Plugins → Vyom → Satellite Indices**.

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2. Select the satellite and enter the time period for which data is required. 

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3. Select the resolution and maximum percentage of cloud cover for the data to be downloaded.  
4. Click **Next**.

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5. Choose from the available dates within the selected time period and select the **NDVI index**.  
6. Click **Calculate**.

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7. Visualize and save the NDVI raster for the year 2025.  

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8. Repeat the process to calculate the NDVI for the year 2018.

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9. Visualize and save the NDVI raster for the year 2018.  

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            :alt: NDVI Visualization 2018
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Step 3: Change Detection
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Compare the two NDVI layers to identify regions of vegetation loss.  

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        :align: center