From the dataset abstract
Old detailed plans of Helsinki. The detailed plan maps for years 1820, 1838 and 1878 can be downloaded as TIFF-files. The guidemaps for all years can be found through WMS API....
Additional Information
| Field | Value |
|---|---|
| Format | TIFF |
| Size | 775.0 MB |
| Published | 16.03.2017 |
| Updated | 26.03.2020 |
| Position coordinates | ETRS-GK25 |