What is a primary use of a locator in GIS?

A locator in GIS is primarily used for geocoding, which involves converting addresses or other location descriptions into geographic coordinates such as latitude and longitude. This process enables the mapping and analysis of various data points based on their spatial context. By transforming textual location information into a format that can be utilized within the GIS framework, geocoding allows users to visualize and analyze data geographically.

Other processes noted in the options, like data analysis, mapping, and raster analysis, do play critical roles within GIS, but they do not specifically focus on the primary function of a locator. Data analysis generally refers to examining data for patterns and insights, mapping deals with the visual representation of data, and raster analysis pertains to operations on raster data formats. None of these encompass the specific purpose of a locator, making geocoding the most accurate and relevant choice.