In this lab you will learn how to conduct unsupervised classification in Erdas Imagine and mosaic two images.
For this lab, you will extract thematic land-cover
information from a TM image (germtm.img) using an
unsupervised classification method and mosaic two air photos (air-photo-1.img
and air-photo-2.img). The image files can be found in I:\Students\Instructors\Geoffrey_Duh\GEOG4581\Lab5.
The lab data files are also in the C:\Program Files\IMAGINE 8.7\examples folder
on the lab computers. Copy these files to your working folder before you begin.
Unsupervised Classification
Read pages 203-217 of the Erdas Field Guide paying particular attention to pages
213-217. Open the Tour Guide and skim Chapter 5.
Complete the tutorial exercise in Chapter 5 and make sure you define each of the 10 classes using the classification scheme shown in the table below. Some classes will have the same class name. Produce a map composition of the classified map that includes a legend with the 10 class names. Put your name on it with a text box and print it. Write one paragraph describing how the map was created including a brief description of the ISODATA process and what the different menu choices mean within the Erdas ISODATA menu.
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Land-cover classification |
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Water |
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Crop/Pasture |
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Impervious/Bare soil |
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Residential |
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Others |
Continue to complete the tutorial exercise in Chapter 7. Use the following instructions to supplement the instructions in the Tour Guide.
1. Before you run the subset utility, open the germtm.img file in a viewer. Use the inquire box to specify an area that just covers the larger lake sitting in the middle of the image. Click “From Inquire Box” button in the subset dialog window. Then, click OK to run the subset utility. This will let you subset only a small section of the input image.
2. Use Windows explore to locate the germtm.tfw. Double-click the file and select either Notepad.exe or Word.exe to open and view the world file. Insert the picture of the subset image and a copy of the world file in your report.
Image Mosaicking
Complete the “Mosaic Using Airphoto Images” tutorial exercise in Chapter 14 (pages 289 to 303). Produce a map showing the original individual images and the mosaicked image.