Annotations are central to effective data communication, yet most visualization tools treat them as secondary constructs -- manually defined, difficult to reuse, and loosely coupled to the underlying visualization grammar. We propose a declarative extension to Wilkinson's Grammar of Graphics that reifies annotations as first-class design elements, enabling structured specification of annotation targets, types, and positioning strategies. To demonstrate the utility of our approach, we develop a prototype extension called Vega-Lite Annotation. Through comparison with eight existing tools, we show that our approach enhances expressiveness, reduces authoring effort, and enables portable, semantically integrated annotation workflows.
@article{arxiv.2507.04236,
title = {AnnoGram: An Annotative Grammar of Graphics Extension},
author = {Md Dilshadur Rahman and Md Rahat-uz- Zaman and Andrew McNutt and Paul Rosen},
journal= {arXiv preprint arXiv:2507.04236},
year = {2025}
}