What defines a Relational Database in GIS?

A relational database in GIS is defined as a collection of ordered sets of attribute data linked by a unique identifier. This structure allows for the organization and management of spatial and attribute data in a way that facilitates complex queries and analyses. Each set of data, often referred to as a table, can be related to other tables through common fields or unique identifiers, which enables the integration of various data types and the establishment of relationships between them.

In this context, having a unique identifier is crucial because it ensures that each record can be distinctly accessed and associated with related records in other tables. This relational aspect supports efficient data retrieval, manipulation, and relationships which are fundamental to GIS applications.

Other concepts mentioned in the options do not accurately capture the essence of a relational database. Real-time survey data reflects temporal data acquisition rather than the structured organization of data. The display of data in 3D pertains to visualization techniques, which is separate from the database structure itself. Lastly, the conversion of data into raster format relates to data processing rather than how that data is organized in a database. Thus, the essence of a relational database focuses on ordered sets of data and their interrelationships.