GIS Day is an annual event celebrating the technology of geographic information systems (GIS) that was initiated by spatial analytics world-leader Esri, and which first took place in 1999. Esri president and co-founder Jack Dangermond credits Ralph Nader with being the person who inspired the creation of GIS Day. He considered the event a good initiative for people to learn about geography and the many uses of GIS. He wanted GIS Day to be a grassroots effort and open to everyone to participate. GIS Day is an annual event celebrating the technology of geographic information systems (GIS) that was initiated by spatial analytics world-leader Esri, and which first took place in 1999. Esri president and co-founder Jack Dangermond credits Ralph Nader with being the person who inspired the creation of GIS Day. He considered the event a good initiative for people to learn about geography and the many uses of GIS. He wanted GIS Day to be a grassroots effort and open to everyone to participate.