Species and habitats - Maja brachidactyla - Presence probability (2006-2012)

Abundances were recoded in term of presence-absence. Geostatistical interpolation : the spatial variation of biological data were analysed using GENSTAT (GENSTAT 7 Committee, 2004), which is a GENeral STATistics package including the main geostatistical tools. It computes experimentala variograms, fits these with various authorised mathematical models and uses them to calculate kriged estimates on a fine regular grid (of latitudes and longitudes). The grid of points was imported into ArcMap and interpolated with the Spatial Analyst extension in order to create a continuous raster of 1 km² resolution. The resulting maps illustrate the spatial distributions and the variations over time for biological data studied in CHARM's area. For legends of maps, approximates of the 5th and the 95th quantiles were used for the minimales and maximales values respectively.生物丰度以有无（presence-absence）形式进行重编码。地质统计插值分析环节：本研究采用GENSTAT统计软件（GENSTAT 7委员会，2004）分析生物数据的空间变异，该软件是一款集成了主流地质统计工具的通用统计分析包。其可计算实验变异函数，采用多种合规数学模型对变异函数进行拟合，并基于精细的经纬度规则网格计算克里金（kriging）插值估计值。随后将该点网格导入ArcMap软件，借助空间分析（Spatial Analyst）扩展模块完成插值处理，最终生成分辨率为1平方千米的连续栅格数据。所得地图清晰展示了CHARM研究区域内目标生物数据的空间分布格局及其随时间的动态变化。在地图图例制作中，分别以第5百分位数和第95百分位数的近似值作为栅格数据的最小与最大取值基准。