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Exercise 2: Quantifying the deforested area (cont'd) 
1. Based on what you saw in the colour composites, which colour represents which class in the land cover map you just created? 2. Explain how and in which bands their spectral characteristics can differ. Select Report/Class statistics to see a window that displays the percentage of area that each class occupies in the image. This will help us determine how much forest disappears every ten years. Save this land cover map as Rondonia_1989_landcover. You can close the original images. Now do the same for the years 1999 and 2009, so that you end up with three land cover maps. Notice that each time, you also get a Report/Statistics window that displays the percentage of area that each class occupies in the image. Create a table to collect the distribution of the two classes both in Frequency (percentage) and in number of pixels for the years in question.
3. Describe the changes between 1989 and 2009 based on the classified images.
4. When comparing the classified image with the false colour images, describe the accuracy of the classification. Where do errors occur? 5. With the knowledge that there are 989 x 1007 pixels in the image, with a size of 150 x 150 meters, calculate the area of forested and deforested land for each year. Put these results in a graph to see how much the forested area has decreased from 1989 until 2009. 6. Calculate the total rate of change from 1989 to 1999, and 1999 to 2009. Last update: 16 April 2013
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