# Usefulness of OSM and BDOT10k Data for Developing Tactile Maps of Historic Parks
## 3 Results  
### Evaluation of OSM and BDOT10k Data Usefulness for Three Levels of Map Detail  
At the first and most general level, a total of 31 characteristic park objects and features were listed, forming the basis for the development of tactile maps. As many as 27 of them represented geometric objects. The assessment excluded the features that could not be presented by geometry, such as terraces or the main axis (Table 1). An example of BDOT10k and OSM data for Wilanow Park is presented in Figure 3.  
For six BDOT10k objects and seven OSM objects, separate layers were created. They, respectively, represented 22% and almost 26% of all objects (Table 1). Over 53% of OSM objects and 61% of the BDOT10k objects had descriptive attributes that made it possible to identify the target object types or/and their qualitative features. Names were only available for four objects in BDOT10k and six objects in OSM (Figure 4a). Figure 3: Databases for Wilanow Park: (**a**) BDOT10k; (**b**) OSM. Figure 2: Location of garden parks in 5 styles: Renaissance, Baroque, Romantic/Sentimental, Landscape/English, and Oriental/Japanese. In the category of geometry existence, the BDOT10k database was considered better- with 70% of objects with geometric data (Figure 4b). The best assessment of BDOT10k and OSM data suitability for the development of tactile maps was obtained in the fifth category--geometry correctness, with 70% of BDOT10k data and more than 72% of OSM consistent with the geometry needed for tactile maps. The assessment of BDOT10k and OSM data for the development of tactile maps showed that, although OSM obtained better results than BDOT10k in three of five database categories, the scores in individual categories were similar (Table 3). The total DUI (Data Usefulness Index) value of the BDOT10k data was 0.49, while the DUI value for OSM was 0.48. The second level of detail of tactile maps was characterised by an increase in the number of objects determining the style of the park. For all park styles, the number of objects on the maps was 39. The largest increases were noted in the vegetation class and garden architecture and equipment (Table 2). For four categories, the data assessment of BDOT10k and OSM decreased. Only for seven BDOT10k objects and eight OSM objects was the existence of a separate layer observed, mainly concerning buildings and paths. For 59% of BDOT10k objects and almost 50% of OSM objects, the existence of descriptive attributes useful for the development of tactile maps was observed. Similar to the first level of detail, the number of OSM objects with names was higher than in the case of BDOT10k, with 16% for the former and more than 10% for the latter (Figure 5). Figure 4: Usefulness of BDOT10k and OSM data—the first level of map detail: (**a**) sum of points; (**b**) percentage of points. Figure 5: Usefulness of BDOT10k and OSM data—the second level of map detail: (**a**) sum of points; (**b**) percentage of points. For the second level of detail, a significant decline was observed in the category of geometry existence. For OSM, it was over 47%, while for BDOT10k, it was over 48%. This is due to the appearance of new objects, which are characteristic of a park but not present in the databases, such as antique elements or plant containers (urn, pot, crate, bucket, jardiniere). At this level of detail, BDOT10k was considered to be better in three of the five categories. The total DUI of BDOT10k and OSM was lower than for the first level of map detail: 0.40 for BDOT10k and 0.39 for OSM. The third level of detail concerned 13 objects necessary for the development of tactile maps (Table 3). The number of water bodies and garden architecture objects and equipment decreased significantly. Only for one object was there a separate layer in the OSM and BDOT10k databases. The descriptive attributes in both cases constituted 46% and 30%, respectively. The assessment in the category of geometry existence decreased. Only for 26% of BDOT10k objects and 19% of OSM objects did suitable geometry exist (Figure 6b).