1. Old Dominion University Summer Research Progress: Week 1 – Hydrology, the Fourier Transform, and Spectrograms George Fava Department of Electrical and Computer Engineering Temple University URL:

2. Old Dominion University: Slide 1 Indian Creek Modeling Hydrology is the study of the movement and distribution of water throughout the Earth (http://en.wikipedia.org/wiki/Hydrology) Dr. Boufadel’s data, chair of the Civil Engineering department Raw data was non-uniformly spaced Interpolation of data using the Nearest Neighbor approach 3-D Mesh plots were generated to visual the contours of the data

3. Old Dominion University: Slide 2 Testing of MATLAB’s Interpolation Methods Linear Cubic Nearest Neighbor

4. Old Dominion University: Slide 3 Extraction of Data from the Mesh Plot Zero and Ninety degree lines were drawn through the origin of the 3-D Nearest Neighbor Mesh plot

5. Old Dominion University: Slide 4 Extraction of Data from the Mesh Plot Z-axis or “Height” data was extracted from these lines and was used as inputs for the Fourier Transform (Zero degree data from left to right) (Ninety degree data from bottom to top)

6. Old Dominion University: Slide 5 Extraction of Data from the Mesh Plot “Fast” Fourier Transform of the Z-axis data using Magnitude plots of the data are shown to visual the frequency content

7. Old Dominion University: Slide 6 Line Data Summary

8. Old Dominion University: Slide 7 Audio Spectrogram Spectrograms measure the spectral density of a signal It works by using a short- time Fourier Transform over small chunks, or windows, of data The spectrogram shows: time on the x-axis the frequency value on the y-axis the intensity or density of the frequencies using color for the third dimension