The paper describes a tool designed within the first stage of the European project INVISIP in order to explore geographical metadata in the site planning process. A visual data mining approach is applied to a database of geographical metadata to help the user find an optimal subset of the existing geographical datasets for his particular planning task. It allows the user to perform both confirmative and explorative analysis. The approach is implemented in the Visual Data Mining tool, which integrates different types of visualisations with various interaction functionalities. It includes the interactive communication with the user and the brushing and linking process between different visualisations. The paper also presents an example of an application on a test metadatabase which was created for this purpose.