A GIS Systems Developer designs, codes, tests, and debugs Geographic Information System (GIS) applications. They utilize various programming languages and GIS software to create applications that allow users to interact with geospatial data. They often work with databases, integrate with other systems, and ensure the functionality and reliability of GIS applications. They may also design and implement data models, create maps, and use algorithms to analyze geospatial data. Additionally, they often work with users to understand their needs, troubleshoot issues, and provide technical support. They continuously stay updated with advancements in GIS technologies.