3.2 NDVI and Density Slice

We used ENvironment for Visualizing Images (ENVI) software to analyze satellite imagery. We used the red and near infrared bands to create an infrared image of our study area. The infrared image helped us pull out fragments with denser levels of tree cover that could not be visible in the natural color image. 

 

 

 

Northwestern Ecuador: Infrared image

Classification of vegetation was performed on the Sampling Area by the application of a density slice of the Normalized Difference Vegetation Index (NDVI). The NDVI helped us determine a series of intervals that would highlight the differences in vegetation composition. We used the NDVI values of fragments previously identified to divide the output ranges into values that would show old growth and secondary forest. The density slice included indices of non-vegetated area; these indices also included cloud cover areas that resulted in negative values. For the purpose of our study, those areas were removed in order to leave only areas with positive values. Positive values, indicative of vegetation growth, were divided into Old Growth Forest and secondary forest. 

NDVI Northwestern Ecuador

ENVI Density Slice of Sampling Area