The continuous updating of IOER Monitor geo base data is a time consuming process, as all changes in topography (including land use) have to by mapped by hand from orthophotos. Basic updating of mapping sheets (the primary data unit) occurs in a three-year cycle (in some states a five-year cycle). The size of trapezoid maps sections (approx. 4, 25 or 100 km²) depends on the state, the type of map and the latitude. The topicality of topographic information will vary according to the map.
Furthermore, there is a distinction between base and peak topicality of the geo base data. The ATKIS Basis-DLM is regularly updated by official surveying agencies, thereby ensuring the base topicality of the individual maps. Changes to particularly important topographic features (primarily in the area of transport) are reflected in geo base data as part of peak updating at 3, 6 or 12 monthly intervals.
Unlike statistical data, it is generally impossible to give a general statement of topicality for ATKIS data (in the form of a specific date) on administrative units that are spread over several individual maps. Thus a spatially-weighted (base) topicality is calculated for every spatial unit in terms of a specific month, displayed beside every indicator value and illustrated in an accompanying map. The base topicality of an indicator value for a municipality can differ from that of the superordinate district or the national level.
The time frame in the interactive map selection within the IOER Monitor reflects the date at which data is made available, generally January of the following year. The actual topicality usually one or two years earlier (comparable with the figures in the Statistical Calendar).