As a crucial part of the digital economy, the shift towards data intelligence is driving the forefront of smart city development. In smart city projects, diverse unstructured data like images, videos, and audio plays a vital role in applications like smart transportation, security, and environmental monitoring. With the rapid growth of data in smart cities, efficiently and accurately labeling this unstructured data poses a significant challenge. In this context, the demand for efficient, high-quality, and professional data annotation services becomes essential. Stardust AI, through its top-tier platform Rosetta, has gained extensive experience in annotating smart city data, contributing robustly to the data-driven progress of smart cities.