Alessio Di Lorenzo is a marine biologist and has an MSc in Geographical Information Systems (GIS) and Remote Sensing. Since 2006, he has been dealing with the analysis and development of GIS applications dedicated to the study and spread of environmental and epidemiological data. He is experienced in the use of the main proprietary and open source GIS software and programming languages.

Dara O'Beirne is a certified GIS Professional (GISP) with over eight years of GIS and Python experience. Dara earned both his Bachelors and Masters of Arts degrees in geography from San Francisco State University. Dara is currently a GIS Analyst working at Arini Geographics in Santa Clara, CA. Before joining Arini Geographics, Dara was a GIS Analyst and technical lead at Towill Inc., a GIS and Land Surveying company in Northern California. At Towill, Dara played a central role in developing and implementing procedures related to the collection and analysis of LiDAR data for environmental and engineering applications. Prior to Towill, Dara gained his professional GIS experience working for the Golden Gate National Recreation Area managed by the National Park Service, one of the largest urban park systems in the world, which includes National treasures, such as Alcatraz, Muir Woods, and the Marin Headlands. His Master's Thesis examined the errors associated with measuring tree heights in an urban environment with both traditional field methods and airborne LiDAR data.

Marjorie Roswell is a web developer and map maker from Baltimore, MD. She purchased her first GIS in 1991, and built an application to assist citizen callers to the Baltimore Office of Recycling. Recent projects include interactive maps of legislative scores, political endorsements, committees, election data, and advocacy interests.

Her site http://committeemaps.org/ details Congressional committee membership, while the site http://farmbillprimer.org/ is devoted to mapping and charting federal food and farm policy.

Marjorie is the author of Drupal 5 Views Recipes, Packt Publishing. She was the technical reviewer of jQuery UI 1.10, The User Interface Library for jQuery, Packt Publishing.

Mark Pazolli is an engineer and data scientist who uses ArcGIS and Python to help his employers decipher the mountains of data they keep on the assets of the Western Australian electrical network. He has qualifications in Electrical Engineering, Computer Science, and Applied Mathematics. He appreciates excellent design and enjoys building interesting things.