Lab 7: Advanced Classification and Accuracy Assessment (Due by 4pm Mar 16)

Total points: 15

Introduction

In this lab you will learn how to conduct supervised classification of satellite imagery. You will learn several different methods of creating and evaluating signatures as well as how to measure the accuracy of your classification.  

Instructions

Read pages 261 to 280 on the Field Guide before you start this lab. For this lab, you will use supervised classification to extract thematic land-cover information from the same TM image (germtm.img) you used in Lab 6. The image file can be found in I:\Students\Instructors\Geoffrey_Duh\GEOG4581\Lab7. Copy the file to your working folder before you begin. Complete the supervised classification part of the tutorial exercise (pages 479 to 510) and produce a map composition of the classified map and its legend. Put your name on the map with a text box. Then do an accuracy assessment (pages 521 to 532, begins from “Use Thresholding” and ends right before “Using the Grouping Tool”) and generate your classification accuracy report. Please generate 25 random points, instead of 10, for this exercise. Answer the following questions.

1. Explain each of the different ways you defined signatures.
2. What do you look for on the histograms of signatures when evaluating those signatures? Attach screenshots of the signature histograms you generated for illustration.
3. What is signature separability? Describe the separability of your signatures using the Transformed Divergence (TD) index.
4. What do the univariate signature editor statistics tell you?
5. Explain the decision rules (classifiers) that you used to produce the supervised classification.
6. Explain the accuracy assessment report.  Make sure you explain what the different numbers of the error matrix and overall accuracy values mean.
7. Attach your classified map and classification accuracy report here.