The capital of the information society is digitised data. Data exchange and continuous use of data are difficult due to the wide range of available data formats (DBF, DXF, ASCII ... see hereunder) and application software, and thus the most valuable of all assets - your data - is left unused or needs additional investment in cost intensive reorganisation and restructuring. IMMI's powerful ArcGIS filter offers a real solution to the problem. The bi-directional filter allows import and export of project data between both worlds: GIS - the most powerful platform to manage geo-referenced data - and IMMI - The Noise Mapping Software. And, best of all, it is easy to use ... and there you go to reuse the topographic and geometric base data of your noise projects for other applications like air pollution modelling, land-use planning, city planning ... or you import data prepared for these applications and use them in your noise mapping project. Reusing existing data lead to economies of scale as the costs related to manual digitising, database programming, data management and maintenance are split over several budgets. The solution: using a filter to import and export data rather than just a plain 'take-it-or-leave-it' interface is the key advantage of the solution offered by IMMI. The filter can be tailored to suit your needs and you will end up importing just the data you need for your project thereby reducing file sizes in IMMI - and smaller files demand less storage room, less processing power and are much quicker and more easy to handle. And the filter does it all: from the simplest geometry to a complex city with hundreds of thousands of buildings, everything can be imported. With the filter the user creates the link between ArcGIS themes and IMMI element types. Both geometric objects (contained in the actual .SHP shape file) and their corresponding attributes (contained in the .DBF database file) are imported and the connection between both is handled by IMMI (using the ArcGIS .SHX index file to recognise the links).