Posts in Data Analysis
GOES-R Satellite Latitude and Longitude Grid Projection Algorithm

Calculating latitude and longitude from a GOES-R L1b data file. The GOES-R L1b radiance files contain radiance data and geometry scan information in radians. This information is not enough to plot geographic radiance data right from the file, however, after some geometric manipulation harnessing satellite position and ellipsoid parameters, we can derive latitude and longitude values from the one-dimensional scan angles and plot our data in projected formats familiar to many geographic information tools.

Read More
Audio Processing in Python Part III: Guitar String Theory and Frequency Analysis

In this continuation of the audio processing in Python series, I will be discussing the live frequency spectrum and its application to tuning a guitar. I will introduce the idea of nodes and antinodes of a stringed instrument and the physical phenomena known as harmonics. This will give us a better idea of how to tune the guitar string-by-string and also discern the notes of a given chord - all calculated using the FFT function in Python.

Read More
Audio Processing in Python Part II: Exploring Windowing, Sound Pressure Levels, and A-Weighting Using an iPhone X

Raspberry Pi 3B+ acoustic analysis using Python. Audio recording and signal processing with Python, beginning with a discussion of windowing and sampling, which will outline the limitations of the Fourier space representation of a signal. Discussion of the frequency spectrum, and weighting phenomenon in relation to the human auditory system will also be explored. Lastly, the significance of microphone pressure units and conversion to the decibel will be briefly introduced and explained.

Read More
Audio Processing in Python Part I: Sampling, Nyquist, and the Fast Fourier Transform

Fourier Series has been widespread in applications of engineering ranging from heat transfer, vibration analysis, fluid mechanics, noise control, and much more. After evolutions in computation and algorithm development, the use of the Fast Fourier Transform (FFT) has also become ubiquitous in applications in acoustic analysis and even turbulence research. In this tutorial, I describe the basic process for emulating a sampled signal and then processing that signal using the FFT algorithm in Python. This will allow the user to get started with analysis of acoustic-like signals and understand the fundamentals of the Fast Fourier Transform.

Read More
Heat Transfer of the Raspberry Pi Using Arduino, An Infrared Thermometer, and Type-K Thermocouple
Geospatial Analysis Using QGIS and Open-Source Data

Geographic information systems (GIS) are powerful tools used by climatologists, health organizations, defense agencies, real-estate companies, and nearly all professions that rely on location-based data. Geographic data is often very cumbersome to analyze traditionally, which is why visualization tools are essential. Depending on the size and complexity of the data, several robust GIS softwares exist on the market from open-source (free) to paid subscriptions. Each software has its strengths and weaknesses, so depending on the application one software may be more effective than another. A few of the leading softwares are: GE Smallworld, Google Earth Pro, AutoCAD Map 3D, and Maptitude. QGIS is an open-source competitor to ArcGIS, which is arguably the industry leader in the GIS market, so for financial and ease-of-application reasons, QGIS is employed here. I will also cover four scales of geographic analysis: one at the city level (NYC), one at the state level (Washington State), one at the country level (U.S.A.), and one at the world level. The goal is to demonstrate the power and breadth of geographic information systems at any scale.

Read More