Physical loss (HOLAS 2)

Physical loss pressure layer combines all human activities that cause physical loss of seabed. The pressure is given as area lost in each cell (km2). For the polygon datasets the area was assumed to be the lost area. For line and point datasets spatial extents were calculated with buffers (below in brackets). If no buffer extent is indicated, the data was reported as polygon. The human activities used for the physical loss pressure: - Bridges (2 m) - Cables (operational; 1,5 m) - Coastal defence and flood protection (area of polygon, 50 m for lines) - Dredging (capital dredging, Area of polygon or a 25/50 m buffer for <5000 m3 / >5000m3 points) - Extraction of sand and gravel - Finfish mariculture (150 m) - Harbours (polygon with 200 m buffer) - Land claim (area of polygon, 30m buffer for lines) - Marinas and leisure harbours (200 m) - Oil platforms (25 m) - Oil terminals and refineries (200 m) - Pipelines (operational; 15 m) - Shellfish mariculture (area of polygon, 150 m points) - Watercourse modification (50 m) - Wind turbines (operational; 30m point location of turbine) The datasets were first processed separately covering the whole Baltic Sea and then merged into one uniform data layer and minimizing the effect of overlapping areas. Polygon areas were clipped with coastline to remove buffered areas that reached to land.物理损失压力图层整合了所有会造成海底物理毁损的人类活动，该压力以每个网格单元的损失面积计量，单位为平方千米（km²）。 对于多边形数据集，其面积直接认定为损失面积。对于线状与点状数据集，其空间范围通过缓冲区（详见下文括号标注）计算得出。若未标注缓冲区范围，则该数据以多边形形式上报。 用于构建该物理损失压力图层的人类活动包括： - 桥梁（2 m） - 电缆（运营中；1.5 m） - 海防与防洪设施（多边形取其面积，线状要素采用50 m缓冲区） - 疏浚工程（基建疏浚：多边形面积为损失面积；点状数据按疏浚量区分，小于5000 m³时采用25 m缓冲区，大于5000 m³时采用50 m缓冲区） - 砂石开采 - 海水鱼类养殖（150 m缓冲区） - 港口（带200 m缓冲区的多边形范围） - 围海造地（多边形取其面积，线状要素采用30 m缓冲区） - 游艇码头与休闲港口（200 m缓冲区） - 石油平台（25 m缓冲区） - 油库与炼油厂（200 m缓冲区） - 管道（运营中；15 m缓冲区） - 贝类养殖（多边形取其面积，点状要素采用150 m缓冲区） - 河道改造（50 m缓冲区） - 风力发电机组（运营状态；以风机点位为中心的30 m缓冲区） 所有数据集首先针对整个波罗的海海域分别进行处理，随后合并为统一的数据图层，并尽可能降低重叠区域的影响。多边形面积通过海岸线裁剪，以剔除延伸至陆地区域的缓冲区范围。