6 - Surface Realisation

Summary

In this chapter we look at the process of mapping an abstract text specification and its constituent phrase specifications into a surface text, made up of words, punctuation symbols, and mark-up annotations. This is known as surface realisation. Much of this discussion is centred around three software packages (kpml, surge, and realpro) which can often be used to carry out part of the mapping process.

Introduction

In the previous chapter, we saw how a text specification can be constructed from a document plan via the process of microplanning. The text specification provides a complete specification of the document to be generated but does not in itself constitute that document. It is a more abstract representation whose nature is suited to the kinds of manipulation required at earlier stages of the generation process. This representation needs to be mapped into a surface form, this being a sequence of words, punctuation symbols, and mark-up annotations which can be delivered to the document presentation system being used.

As described in Section 3.4, a text specification is a tree whose leaf nodes are phrase specifications and whose internal nodes show how phrases are grouped into document structures such as paragraphs and sections; internal nodes may also specify additional information about structures, such as section titles. Phrase specifications describe individual sentences; they may also describe sentence fragments in cases where these fragments are realised as orthographically separate elements (such as section titles or entries in an itemised list).