These results suggest that the use of colour and orientation as visual variables in combination can improve the selectivity of map symbols and user performance during the exploration of geographic data in some scenarios. Choriented maps and choriented mobile visualizations also performed well regarding efficiency overall and performed worse only than graduated symbol maps. Choriented maps and choriented mobile visualizations resulted in comparable, sometimes better effectiveness and confidence scores than choropleth and graduated symbol maps. The maps were evaluated in a graphical perception study featuring the comparison of SDG (Sustainable Development Goal) data for several European countries. To mitigate this issue, this work introduces two new visualization types: choriented maps (maps that use colour and orientation as variables to encode geographic information) and choriented mobile (an optimization of choriented maps for mobile devices). However, as the number of classes grows, distinguishing between adjacent classes increasingly becomes challenging. The prototype and insights gathered from the user study are relevant to making cartographic products more accessible to a broader population, and open geographic data more usable in the context of an open government.Д¬horopleth maps and graduated symbol maps are often used to visualize quantitative geographic data. Results from the user study suggest that despite facing a few challenges in accurately identifying StevensвЂ™ data types, participants managed to successfully create web maps and correctly answer spatial questions. It was implemented as a web prototype in AngularJS and evaluated with 19 participants. The approach relies on the mapping between StevensвЂ™ data types and BertinвЂ™s visual variables, to suggest (meaningful) thematic map visualizations for a given input geographic dataset. This article introduces a semi-automatic approach for the creation of thematic web maps by and for users with no prior training in cartography. As a result, they pose several challenges to non-experts wanting to adapt them to new scenarios. Current thematic web maps are created by programmers and/or cartographers, and thus are not designed to be easily reused with new geographic datasets. Thematic web maps are key to understanding these open geographic datasets.

Open data portals have been emerging all over the world as mines of open geographic datasets. Open government promises increased transparency by providing its citizens datasets about city processes.

Kra webmap