The paper adopts a citation-based analysis to survey the big data relevant literature from 2001 to 2016 to identify the major research themes over the past decade. Databases of Web of Science (WOS) and Scopus are used to retrieve the relevant articles. The edge-betweenness clustering technique is applied to the citation network that is built from the retrieved data. The major research groups in the big data field are identified via the clustering. A word clouding is used to extract the major research themes of each group by calculating the frequencies of words used in the titles of articles. Eleven major and minor research themes are identified: ``cloud computing{''}, ``data mining{''}, ``MapReduce{''}, ``privacy{''}, ``social media{''}, ``healthcare{''}, ``ethics and legal{''}, ``surveillance{''}, ``geography{''}, ``business intelligence{''}, and ``bioinformatics{''}. The approaches presented in this paper can also be applied to any scientific or technological field.