Open data portals are web services that serve as a central access point for all government-published open data and can exist at local, regional, national, and international levels. They are an important element of most open data initiatives that have enabled a large amount of government data to be widely available. However, data quantity and quality are not the only aspects that should be considered when publishing data. To improve the reusability of data and to achieve greater impact and benefits from open data, it is important to consider user-oriented aspects of the portal management, discovery, and use of data (e.g., organizing the portal in a user-centric way, providing accurate metadata, using a standardized and open data format, etc.). In this paper, we adopted the metrics proposed by the European Commission to assess compliance of the Croatian Open Data Portal with 10 user-oriented principles that open data portals should implement in terms of sustainability and added value. While the results show the government’s efforts in publishing data, some aspects such as better collaboration with data providers and other data portals, offering different visualization tools, etc. need to be improved to achieve active use and impact.

Geovisualizations based on open data are increasingly used as public-facing interfaces for communicating geospatial information, yet their evaluation often remains limited to isolated design, usability, or technical aspects. This study addresses that gap by developing and applying an integrative evaluation framework that combines four analytical dimensions: cartographic representation, interaction and engagement affordances, openness, and accessibility, while treating contextual characteristics as conditioning factors. The framework is operationalized through a mixed-methods content analysis of 26 publicly available geovisualizations based on open data. The results show that most cases are produced by public-sector actors, focus on environmental and transport themes, and rely on conventional cartographic techniques combined with medium levels of interactivity that support structured exploration rather than deeper analytical reasoning. Although many geovisualizations cite data sources and provide some form of data access, licensing remains inconsistent, particularly for the visualization artefacts themselves, limiting reuse potential. Accessibility is implemented even less consistently across geovisualizations, with recurring shortcomings in color contrast, keyboard navigation, screen-reader compatibility, and multilingual support. Overall, the findings suggest that the broader societal potential of geovisualizations based on open data may not be determined by individual features, but by balanced cross-dimensional configurations. Strengthening the integration of openness and accessibility alongside interaction and design may enhance the potential of geovisualizations to support reuse, inclusiveness, and public engagement.

The content of the data lake comes (is filled) from different sources, and different users (experts in various fields) of the same data can download and analyse the same data for their (different) needs and analysis. Big Data about the human environment and the effect of natural and human-caused disasters (in this case: heat islands, earthquakes and lava flows, and landmine contamination) on that environment have been available to many people for years and are the subject of discussions, but there are still numerous research challenges in the form of structuring and storing data and analysis results. This implies certain requirements for efficient integration, access and querying of the various data in the data repository for the described purpose. Data lakes and data warehouses are offered as solutions to this problem. Well-designed data lakes can be a basic building block for different solutions in the analysis of the effects of disasters on the environment, and high-quality data warehouses for modelling future potential disasters in the same area. This paper presents certain personal observations and certain proposals for the creation of efficient data lakes and data warehouses (based on many years of work on problems in areas: humanitarian demining, heat islands and volcanic activity) for the needs of decision-making in crisis based on examples from practice. The goal is to influence the development of a unique framework for the creation and maintenance of a data lake, in terms of its better utilization so that it does not become a data swamp.