The GTN-P database is an object-related database open for a diverse range of data. Because of the complexity of the PAGE21 project, data provided in the GTN-P management system are extremely diverse, ranging from active-layer thickness measurements once per year to flux measurement every second and everthing else in between. The data can be assigned to two broad categories: Quantitative data which is all data that can be measured numerically. Quantitative data comprise all in situ measurements, i.e. permafrost temperatures and active layer thickness (mechanical probing, frost/thaw tubes, soil temperature profiles). Qualitative data (knowledge products) are observations not based on measurements, such as observations on soils, vegetation, relief, etc.