The manuscript seeks to improve the pupils understanding of data handling by improving all aspects of visualization in their thinking and be able to employ these strategies to all subjects across the curriculum. This is done through a qualitative examination of the role of visualization through an understanding of the thought processes that occur during visualization when Grade 9 pupils engage in data handling and spatial tasks. Knowledge of the role of visualization enables the educator to encourage the use of visualization during their teaching of data handling. This manuscript answers some questions about visualization for the teacher, for the pupil, for the curriculum developer, and for the mathematics community as a whole. By ignoring visualization curricula not only fail to engage a powerful part of students minds in service of their mathematical thinking, but also fail to develop students? skills at visual exploration and argument. The problem-centred approach provides a suitable environment in which teachers are able to improve visualization during facilitation of learning.