Professional Interests

Dr. Callahan is a recognized expert in data management, analysis and visualization of environmental modeling and monitoring data. In invited presentations, he has represented US science agencies (NOAA, EPA, USFS) at national and international meetings and conferences. Dr. Callahan’s current focus is bringing modern software practices and best available tools to the field of air quality. Over the last decade, he has developed standards and architected solutions that have become agency policy and are used operationally in the US Interagency Wildland Fire Air Quality Response Program.

Personal Statement

Over a four decade career in science, I have seen huge changes in the skillsets required to make scientific analysis reproducible and scientific results useful to the broader public. The “data deluge” is real and software skills are increasingly important when analyzing large amounts of data. At the same time, the need to communicate scientific findings to a broader public requires improved data presentation skills. I am a big believer in collaborative efforts in science and, to that end, have authored numerous open source software packages that assist with data management, data analysis, data visualization and the creation of interactive websites. My goal has always been to make data analysis and visualization easier so that scientists can spend more time on the important part — communicating their results with the public.

Open Source Software in R

Dr. Callahan has published and maintains numerous open source software packages used by scientists and data analysts working with environmental monitoring data. These are designed for use with the open source R statistical analysis language.

• beakr A Minimalist Web Framework for R
• MazamaRollUtils Fast rolling functions for R written in C++
• MazamaCoreUtils Utilities to help write production R code
• MazamaSpatialUtils Harmonized spatial datasets and spatial search functions
• MazamaSpatialPlots Thematic mapping for MazamaSpatialUtils
• MazamaLocationUtils Utilities for working with monitoring site known locations
• MazamaTimeSeries Core functionality for environmental time series data
• AirMonitor Utilities for working with air quality monitoring data
• AirMonitorPlots Plotting functions for the AirMonitor package
• AirSensor2 Utilities for working with data from low-cost air quality sensors
• RAWSmet— Utilities for working with Remote Automatic Weather Station (RAWS) data

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