Web of Things (WoT) uses current Web protocols and languages as an integration platform of physical devices on the Internet. Previsions estimate that by 2020, 20 to 50 billion such devices will be connected - producing, collecting, and transmitting data over the Internet. The amount of data associated with such a gigantic number of available devices represents a real challenge in data visualization. This paper proposes a Data Visualization model for WoT, based on Fog Computing concepts, more specifically the Fog of Things paradigm. The aim of our proposal is to enable the creation of different data visualizations that take into account the hierarchical levels in an architecture involving Fog and Cloud. In order to demonstrate our proposal, a prototype of the Web of Things application was developed, which is used to perform usability evaluation through the USE questionnaire technique.