When it comes to the concept of "map onto," there are a number of synonyms that can be used to convey a similar meaning. For instance, one could use the term "overlay" to suggest a process of putting one set of data or information over another. In a similar vein, one might also use the word "superimpose" to suggest a process of combining two or more pieces of information or data. Another possible synonym might be "fit," which could be used to suggest the process of aligning one set of information or data with another. Ultimately, the choice of synonym will depend on the specific context and the nuances of the information or data involved.