in recent years, topological and geometric data analysis (tgda) has emerged as a new and promising field for processing, analyzing and understanding complex data. indeed, geometry and topology form natural platforms for data analysis, with geometry describing the ``shape'' behind data; and topology characterizing / summarizing both the domain where data are sampled from, as well as functions and maps associated to them. \\ \\ in this talk, i will show how topological (and geometric ideas) can be used to analyze graph data, which occurs ubiquitously across science and engineering. graphs could be geometric in nature, such as road networks in gis, or relational and abstract. i will particularly focus on the reconstruction of hidden geometric graphs from noisy data, as well as graph matching and classification. i will discuss the motivating applications, algorithm development, and theoretical guarantees for these methods. through these topics, i aim to illustrate the important role that topological and geometric ideas can play in data analysis.