This activity guides you through a simulated pixel-based unsupervised classification of remotely sensed image data to create a land cover map. Our goal is for you to gain a hands-on appreciation of automated image classification technique. Begin by viewing and printing the Image Classification Activity PDF file [1].
1. Plot the reflectance values.
The two grids on the top of the second page of the PDF file represent reflectance values in the visible red and near infrared wavelength bands measured by a remote sensing instrument for a parcel of land. Using the graph (like the one below) on the first page of the PDF file you printed, plot the reflectance values for each pixel and write the number of each pixel (1 to 36) next to its location in the graph. Pixel 1 has been plotted for you (Visible Red band = 22, Near Infrared band = 6).
2. Identify four land cover classes.
Looking at the completed plot from step one, identify and circle four clusters (classes) of pixels. Label these four classes A, B, C, and D.
3. Complete the land cover map grid.
Using the clusters you identified in the previous step, fill in the land cover map grid with the letter that represents the land use class in which each pixel belongs. The result is a classified image.
4. Complete a legend that explains the association.
Using the spectral response data provided on the second page of the PDF file, associate each of the four classes with a land use class.
You have now completed the unsupervised classification activity in which you used remotely sensed image data to create a land cover map.
Links
[1] https://www.e-education.psu.edu/natureofgeoinfo/sites/www.e-education.psu.edu.natureofgeoinfo/files/file/ICA.pdf
[2] https://www.e-education.psu.edu/natureofgeoinfo/sites/www.e-education.psu.edu.natureofgeoinfo/files/image/classification_01a.gif
[3] https://www.e-education.psu.edu/natureofgeoinfo/sites/www.e-education.psu.edu.natureofgeoinfo/files/image/classification_02a.gif
[4] https://www.e-education.psu.edu/natureofgeoinfo/sites/www.e-education.psu.edu.natureofgeoinfo/files/image/classification_03a.gif
[5] https://www.e-education.psu.edu/natureofgeoinfo/sites/www.e-education.psu.edu.natureofgeoinfo/files/image/classification_04a.gif
[6] http://gis.e-education.psu.edu