# Multi-Purpose Ontology-Based Visualization of Spatio-Temporal Data: A Case Study on Silk Heritage
## 5 Results and Discussion  
As previously commented, STMaps is a multipurpose visualization tool. However, in order to show some results of the use of our tool in a real scenario, in this section, we provide different examples where we use the STMaps tool to explore data from SILKNOW's knowledge graph, such as the relationships between a set of objects or their temporal evolution. Figure 8: Icons (and their meanings) shown in STMaps for the objects in SILKNOW. Figure 7: Line-based representation of the relationship between the properties of the objects in SILKNOW. As explained above, in order to evidence the relationships among objects, we have implemented two visual strategies: lines and rings. Although with the line-based representation we can visualize the relationship between objects, the importance of the ring-based representation lies in their simplicity and power. With just a glance, we can clearly see if one of the objects has a distinct set of properties with respect to the rest shown on the map. Thus, this allows us to quickly identify singular objects that would otherwise be much more difficult to locate. An example is depicted in Figure 9, where the reader can see the difference in the simplicity and clarity of the two representations. These objects are obtained after a query asking for those objects related to \"espolin\", which might refer to a weaving technique or a type of fabric. This query returns a total of 1900 results in the current version of ADASilk, which can be depicted in STMaps (Figure 9a). Whereas with the line-based representation the map is quickly filled with lines (notice that in Figure 9b we only show the relationship of one of the four properties for just a single object with the rest), the ring-based representation is much clearer (Figure 9c) and provides similar information. However, with the ring-based representation, one needs to zoom in the object, whereas with the line-based representation, greater areas can be depicted. Therefore, both representations are complementary, and either of them can be used depending on the case of study. On the other hand, the rings also make it easy to visualize objects with incomplete data, as they appear as unrelated to the rest of objects. An example is shown in Figure 10. For the objects depicted in Figure 10a, there are some of them that are not related to any of the objects of the query, for some of their properties, and thus, some ring sections appear in light color. By clicking on one of the objects (Figure 10b), it can be seen that the properties  
Figure 9: Examples of relationship visualization, where: (**a**) results of a query for objects related to the term “espolin”; (**b**) visualizing the objects that have the same value for the “category” property than a single object, selected by the user, with the line-based representation; (**c**) visualizing how many objects are related for each object of a query, for the four properties (“technique”, “material”, “time” and “category”), for a small set of objects, using the ring-based representation; (**d**) inspecting the percentages in detail, for one of the objects (the same used in (**b**)). \"technique\" and \"material\" are unrelated (0%) to the rest of objects, and by inspecting the details of the object (Figure 10c), it can be seen that these properties are empty, and thus, this information is incomplete. To show the relevance of dealing with a correct representation of objects with multiple location and/or time spans, we show in Table 2 the total number of records that are currently included in ADASilk that have location (production place) and/or time (production time) information. For these records, we show how many of them have multiple locations and/or time spans, and the percentage that they represent.