What is authentication in GIS applications?

Authentication is verifying the identity of a user requesting access to a GIS platform or geo service. Usually via username and password, SSO, or federated login (for example government ID).

Without reliable authentication the system does not know who performs actions: viewing maps, editing data, or exporting. In GeoApps and enterprise GIS, Active Directory or SAML integration is common.

Authentication determines who you are, not what you may do. That belongs to authorization. Both are needed for secure access to sensitive geodata.