Lab 8 - Spectral Signature Analysis & Resource Monitoring

GOAL AND BACKGROUND

The goal of this lab is to explore spectral signature analysis. This includes learning to graph and interpret reflectance information along learning simple band ratio analysis techniques.


METHODS

First, examples of various surfaces were found within the study area, Chippewa and Eau Claire Counties. This included standing water, moving water, forested areas, riparian vegetation. crops, urban grass, dry soil, moist soil, rock, asphalt highways, airport runways, and a concrete surface. The reflectance bands of each of these areas was then graphed and interpreted.

Next, band ratio analysis was explored. First, NDVI was used, which creates a ratio of NIR and the red band. This shows areas of healthy vegetation. After this was performed, ferrous minerals were analyzed using a ratio of MIR and NIR.


RESULTS

Shown below is the plotted bands of various surfaces. The IR bands (4-6) are the most effective at differentiating between the channels, as there is the most variation.Vegetation tends to have a high reflectance in these bands because IR is damaging to plants. However, water tends to readily absorb IR, which can be used in determining the water content in surfaces, such as soil. This is shown by dry soil having a lower IR absorbance than moist soil.

Shown below are maps of the study area after band ratios were used to determine areas of dense, healthy vegetation and ferrous minerals, respectively.

SOURCES

Satellite image is from Earth Resources Observation and Science Center, United States Geological Survey.