Data set represents the HELCOM 20x20 km Baltic Sea grid. The grid is based on the European Environment agency (EEA) grid system, and its compatible with other grid sizes. Each grid cell have an unique identifier, that is based on the EEA coding system, where the identifier consists of the cell size and cell coordinates. The grid covers the HELCOM marine area and uses the LAEA projection. HELCOM is making the grid available to offer a standardized and equal area grid system for the Baltic Sea that can be used in different assessments and that is alligned with different grid sizes, such as the "HELCOM 1x1km Baltic Sea grid" or any other EEA based grid system in Europe. The grid is available in two versions: 1. The basic version (HELCOM 20x20km Baltic Sea grid) with full grid cells. This is the version that is visualized in MADS and avaliable for download below as the first link and also as the download link in MADS 2. The second version (HELCOM 20x20km Baltic Sea grid without land areas) where all land areas are removed within the grid cells. This version is not visualized in MADS, but is available for download below. Further details on the 2 different grids can be found in the lineage section below. Attribute information: Unique_ID: Unique ID of the grid cell, based on the EEA coding system Area_km2: Area of the grid cell (for the second version the area is without land areas)

Data set represents the HELCOM 10x10 km Baltic Sea grid. The grid is based on the European Environment agency (EEA) grid system, and its compatible with other grid sizes. Each grid cell have an unique identifier, that is based on the EEA coding system, where the identifier consists of the cell size and cell coordinates. The grid covers the HELCOM marine area and uses the LAEA projection. HELCOM is making the grid available to offer a standardized and equal area grid system for the Baltic Sea that can be used in different assessments and that is alligned with different grid sizes, such as the "HELCOM 1x1km Baltic Sea grid" or any other EEA based grid system in Europe. The grid is available in two versions: 1. The basic version (HELCOM 10x10km Baltic Sea grid) with full grid cells. This is the version that is visualized in MADS and avaliable for download below as the first link and also as the download link in MADS 2. The second version (HELCOM 10x10km Baltic Sea grid without land areas) where all land areas are removed within the grid cells. This version is not visualized in MADS, but is available for download below. Further details on the 2 different grids can be found in the lineage section below. Attribute information: Unique_ID: Unique ID of the grid cell, based on the EEA coding system Area_km2: Area of the grid cell (for the second version the area is without land areas)

Data set represents the HELCOM 1x1 km Baltic Sea grid, that was originally created for the HOLAS II project (State of the Baltic Sea report 2018) and used in the Baltic Sea Impact Index and Shipping density maps produced for HELCOM Maritime Assessment. The grid is based on the European Environment agency (EEA) grid system, and its compatible with all other grid sizes. The grid covers the whole Baltic Sea water area: A grid cell is included in the data set if some part of the 1x1 km cell touches water according to the EEA coastline data set. Same method is applied to cut the grid to match the HELCOM marine area. Attribute information: HELCOM_subbasin_ID: HELCOM subbasin ID where the cell is located HELCOM_subbasin_name: HELCOM subbasin name where the cell is located