Geographic information systems, or GIS, is a tool used to capture and organize spatial data. GIS analysts use these tools to analyze data and present their findings. These findings are used to produce maps and make decisions about land use. Among the top geospatial careers, GIS analysts also do fieldwork, making observations and collecting data, or verifying their findings. In addition to these duties, GIS analysts use technical equipment to anticipate geographic changes and capture those changes in charts and graphs.