DGN/DWG

From the dataset abstract

The Helsinki plan maps are a collection of the city of Helsinki’s valid and overturned detailed plans. The detailed plans and changes to the detailed plans create the conditions for construction. The detailed plan regulates what purposes an area can be used for and how much can be built. The plan maps show the approved detailed plans and changes to the detailed plans. The maps show, for example, the boundaries of the detailed plans, the different detailed plan areas and their identifiers.

The City of Helsinki moved to computer-assisted (CAD) production of detailed plans in the late 1980s. However, even in the 1990s, some of the detailed plans were drawn by hand, so the entire data is not available in vector form. The storage format of the detailed plan maps is MicroStation DGN (2D). The dataset is also available in DWG format.

The Helsinki Map Service includes downloadable, legally valid vector-format detailed plans that have been prepared in this millennium. Many of the plans from the 1990s are also available in vector form. Detailed plans older than this are not available in vector form.

The files can also be retrieved based on the detailed plan number at https://ptp.hel.fi/dataForms/Asemakaavakartat/Default.aspx

Source: Helsingin asemakaavakartat