How to perform Image Classification and Landcover Change in GIS?

Introduction

This tutorial guides you through the process of performing image classification and analyzing land cover change using GIS. By following these steps, you'll gain practical skills in handling Landsat satellite imagery, utilizing tools in ArcMap, and interpreting changes in land cover effectively.

Step 1: Understanding the Purpose and Data Characteristics

• Familiarize yourself with the objective of the lab, which focuses on analyzing land cover changes using Landsat 8 imagery.
• Review the characteristics of the data you'll be working with, including spatial resolution and spectral bands of Landsat 8.

Step 2: Download and Unzip Landsat 8 Imagery Data

• Access the Landsat 8 satellite imagery data by visiting USGS GloVis and selecting Path: 39, Row: 31.
• After downloading, unzip the files using a file extraction tool to access the imagery components.

Step 3: Load Composite Bands into ArcMap

• Open ArcMap and create a new project.
• Add the composite bands of the Landsat imagery to your map by navigating to File > Add Data and selecting the unzipped files.
• Explore the bands visually to understand their characteristics and how they relate to land cover.

Step 4: Visual Examination of Land Cover Change

• Utilize the swipe tool in ArcMap to compare different time periods visually.
• Adjust the transparency of layers to observe changes in land cover between the selected dates.

Step 5: Clip the Images with Area of Interest (AOI)

• Download the AOI shapefile from here.
• Add the AOI layer to your ArcMap project.
• Use the Clip tool in ArcMap to limit the imagery analysis to your specific area of interest.

Step 6: Introduction to Image Classification

• Understand the concept of image classification, which involves categorizing pixels into meaningful classes based on their spectral signatures.
• Familiarize yourself with the difference between supervised and unsupervised classification techniques.

Step 7: Perform Unsupervised Classification in ArcMap

• Open the Image Classification tools in ArcMap.
• Choose the unsupervised classification method, such as ISODATA or K-means.
• Run the classification and evaluate the results to identify distinct land cover classes.

Step 8: Measure Areas of Water Bodies and Land

• Use the Calculate Geometry tool to measure areas of different land cover types, such as water bodies.
• Ensure accurate measurements by verifying the projection and coordinate system of your data.

Step 9: Create Land Cover Change Maps

• Generate maps that visualize the land cover changes over time.
• Use the classified imagery to create thematic maps that highlight changes in specific land cover types.

Conclusion

In this tutorial, you learned how to perform image classification and analyze land cover changes using Landsat 8 imagery in ArcMap. By following these steps, you can effectively visualize and measure changes in land cover, making it easier to understand environmental impacts and trends. Consider exploring additional resources, such as the "Introduction to Remote Sensing in GIS" video, to deepen your understanding of GIS applications.