# AetherGeo: A Spectral Analysis Interface for Geologic Mapping
## 4 Related Software Tools
### Preprocessing  
This category currently has two different functions. The first enables the user to generate a layer composed of a normalized version of the input data. This normalization is conducted through a process that sets the lowest value to 0 and scales the other bands  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Function Group** & **Function** & **Description** & **Input** \\ \hline \multirow{4}{*}{Icon Bar} & \multirow{4}{*}{2D Plot} & Select points from the image based on & \multirow{4}{*}{Image} \\  & & the associated information & \\  & & User Guide & & \\  & & User Guide & & \\  & License & & & \\ \hline \multirow{4}{*}{Preprocessing} & Normalize data & [0, 1] pixel-wise normalization & \multirow{4}{*}{Image} \\  & & Attribute Wavelengths & Add wavelength metadata to the & \\  & & & image & \\ \hline \multirow{4}{*}{Dimensionality Reduction} & Principal Component Analysis [53] & \multirow{4}{*}{Reduce the amount of data while} & \multirow{4}{*}{Image} \\  & & Independent Component & & \\  & Analysis [54] & maintaining the most significant or & & Mask (optional) \\ \cline{1-1}  & & Non-Negative Matrix & independent features. & Number of components to be kept \\ \cline{1-1}  & & Factorization [55] & & \\ \hline \multirow{4}{*}{Endmember Extraction} & Pixel Purity Index & Identify the most extreme pixels in a & \multirow{4}{*}{Image} \\  & & given image & & \\ \cline{1-1}  & & & & \\ \cline{1-1}  & & Generate Point Cloud & & \\ \cline{1-1}  & & & endmembers & \\ \hline \multirow{4}{*}{Spectral Unmixing} & \multirow{4}{*}{Spectral Angle Mapper [56]} & Attributes a value to each pixel based & \multirow{4}{*}{Image} \\  & & on the angular distance between the & & \\ \cline{1-1}  & & pixel spectra and the given input & & \\ \cline{1-1}  & & spectra & & \\ \hline \multirow{4}{*}{Clustering} & \multirow{4}{*}{K-Means [57]} & Performs clustering based on distance & \multirow{4}{*}{Image} \\  & & from the cluster centroid & & \\ \cline{1-1}  & & & & \\ \cline{1-1}  & & & & \\ \cline{1-1}  & & & & \\ \cline{1-1}  & & & & \\ \cline{1-1}  & & & & \\ \hline \multirow{4}{*}{Spectral Libraries} & \multirow{4}{*}{Import Library} & Enables the user to import spectral & \multirow{4}{*}{File path} \\  & & libraries & & \\ \cline{1-1}  & & & & \\ \cline{1-1}  & & Visualization tool for spectral libraries, & \\ \cline{1-1}  & & & their components, and respective & \\ \cline{1-1}  & & & analysis & \\ \hline Others & Band Ratios & Perform calculations based on pixel & \multirow{4}{*}{Image} \\  & & values for input bands & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Software’s main functions.  
proportionally so that the highest possible value is 1, thus normalizing the vector of band values associated with each pixel [59]. This process is important for minimizing the effects of light intensity changes across the scene and maximizing the focus on the structure of the spectrum itself.  
The second function enables the user to attribute the wavelength metadata to an image if that given image lacks previous wavelength metadata and the number of bands associated with it is the same as the number of bands for the selected sensor. This attribution is important for later stages to generate proper spectral libraries with correct wavelength data.