The task to inform about the prices in the property market requires the application of an efficient valuation information system. It is necessary to keep a schedule of purchase prices and to analyse these collected data in a qualified manner. To create land valuation databases for an information system and to enable interoperability with existing IT-solutions and data files, the definitions of objects and data models are harmonized. Building actual databases calls for an inventory of the existing data sources of increase of value real estates in redevelopment zones according to the German planning law. For three decades, collocation has become a standard method for determining the compensatory levy in declared redevelopment zones. The topic of this contribution is to enhance the use of collocation by introducing the expectation-maximization-algorithm. The results of the algorithms are improved and able to give a higher explanation to the compensatory levy in declared renewal zones. This task is executed by using digital methods and the presentation of the results proceeds to modern information technologies. Additionally, this contribution informs about values of real estate in redevelopment zoning in decisions and verdicts of administrative courts.