1. A computer implemented method comprising: receiving a first mapping specification mapping data elements of a first data structure of a first data representation to data elements of a second data structure of a second data representation, the first data structure having a first one or more data elements and a first one or more data element relationships defining a first shape and the second data structure having a second one or more data elements and a second one or more data element relationships defining a second shape, where the first shape and the second shape are not equivalent; receiving a first instance of said first data structure having first instances of said first one or more data elements of said first data structure; and populating data element instances of a first instance of said second data structure with values of said correspondingly mapped data element instances of said first instance of said first data structure in accordance with said first mapping specification.