Lab 8: Spectral Signature Analysis

Background and Goals

The goal of this lab is to introduce students to the process of analyzing and collected various spectral signatures from satellite images. This includes digitizing areas of different materials in order to collect their unique spectral signature and graphing and analyzing the results. Along with creating NDVI images and analyzing ferrous mineral distribution.

Methods

To begin the lab, I brought in an image Western Wisconsin. Once the image was into the viewer I digitized AOI’s (Areas of Interest) across many different land surface features. These features included agricultural fields both planted and un-planted, different types of forest, rocks, and urban development. Once the AOI’s were created I brought them into the Signature Editor (Figure 1)where further analysis could be done. From the Signature Editor I then proceeded to graph the different materials and analysis their signatures across different bands. I then compared the different materials spectral signatures against each other both amongst similar features and amongst features that are different (Figure 2).

Figure 1. Signature Analysis Table

Figure 2. Graph showing the different spectral signatures

After analyzing the different spectral signatures that different features reflect, the next task that I was given was to perform resource monitoring in the form of vegetation health monitoring by creating a NDVI (Normalized Difference Vegetation Index) image and Ferrous Mineral content image of Eau Claire-Chippewa Falls area.  To this I brought in an image of the area and used the NDVI tool to create the new NDVI Image and the Indices Tool to create an image that showed the abundance of Ferrous Minerals. The new images where in black and white so I imported the images into ArcMap and classified the data and created the maps below.

Figure 3. Map displaying the NDVI for the Eau Claire-Chippewa Falls Area

Figure 4. Map displaying the distribution of Ferrous Minerals in the Eau Claire-Chippewa Falls Area

Sources

Earth Resources Observation and Science Center, United States Geological Survey