# Chatbot-Based Natural Language Interfaces for Data Visualisation: A Scoping Review
## 4 Results
### Interaction Space  
The **Interaction space** refers to all the interactions that users can make throughout the different stages of the visualisation pipeline (see Figure 9). In the literature, the use of different interaction styles varies. Most V-NLIs (13/20, 65%) use both Basic (WIMP) and, naturally, Advanced (NL) interactions [15; 39; 40; 63; 69; 70; 84; 85; 86; 88; 90; 91; 92], while (7/20, 35%) of them use only Advanced (NL) interactions [64; 80; 81; 82; 89; 87]. Additionally, in Table 3, we provide information on how each V-NLI used the seven interaction methods proposed by [10]. V-NLIs used the interaction techniques outlined in Table 3 at various stages of the pipeline illustrated in Figure 1. While some V-NLI interactions are designed for only one stage, others included interactions at multiple stages. The most used interaction techniques are select and filter. V-NLIs such as [63; 80; 82; 84] use NL to interact with visualisations selecting (marking a data point) and filtering (showing something conditionally) data according to user queries. Boomerang [82] selects and filters data at the data transformation stage to create visualisations using NL. Data@hand [84] and TransVis [63] also use these techniques at the data transformation stage to update visualisations. Similarly, Refs. [87; 92] use NL to update visualisations using filtering at the data transformation stage, while Chat2 Vis [83] does this to generate visualisations. Others, such as [69; 88; 90; 91], use both direct manipulation and NL to filter visualisations at the visual mapping stage. Refs. [39; 40] use both basic and advanced interaction techniques at the visual mapping stage to filter visualisation and [39] uses advanced interaction while using the select method. Orko [15] and Databreeze [85] use both NL and direct manipulation to filter and select data on visualisations. Moreover, Gamebol [86] asks users if they want to see a visualisation related to their query, and before displaying the visualisation, the chatbots questions to users to filter the data to customise it before visualising and it gives users options with buttons. Similarly, Ava [81] uses NL to interact with data and not visualisations. It uses NL to perform complex data science tasks such as statistical analysis and generating visualisations from libraries. Finally, Ref. [64] uses advanced NLP-based interaction techniques when labelling selected data visualisation (maximum sale), and Ref. [70] uses both interaction styles. The next most used method is Encode [15; 40; 63; 64; 83; 85; 88; 89; 91; 92]. For example, Refs. [15; 40; 85; 88; 91] allow users to colour and size data points and add/remove attributes by using Basic (WIMP) and Advanced (NL) interactions at the visual mapping stage. On the other hand, Valetto [92] and TransVis [63] use NL commands to add or remove attributes at the data transformation stage. Similarly, Iris [89] uses NL to interact with data in Visual Mapping (i.e., users can select different attributes for axis), but not with View  
Figure 9: Interaction Space affects all the steps of the visualisation pipeline. Transformations. On the other hand, Talk2 Data [64] and Chat2 Vis [83] only interact at the Data Transformation stage, allowing NL queries to colour visualisations. The reconfigure method is supported by four V-NLIs [39; 85; 88; 92], which are used to change the visual perspective of the data in the visual mapping. For instance, Valetto [92] uses gestures (a basic interaction) to flip the axis in the visualisation mapping stage. InChorus [88] uses both basic and advanced interaction methods, such as re-ordering data in the step of data transformation, to reconfigure the visualisation. Similarly, in the same step, Databreeze [85] uses a combination of basic and advanced interactions to rearrange data points and Evizeon [39] uses advanced interactions for this task. Furthermore, the explore method, which is considered to be zooming and panning in the View Transformation stage, is used in four V-NLIs [15; 39; 63; 88], all with basic interactions.