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HOLAS II Aggregated pressure layers weighting workspace

Project Summary

345 days ago

Welcome to the workspace on commenting and discussing the weighting factors for aggregated pressure layers used in the Baltic Sea Impact (BSII), Baltic Sea Pressure Index (BSPI) and Potential cumulative impacts on benthic habitats.


The further development of the BSII process also involves exploring a method for weighting of aggregated pressure layers. Currently, the BSII calculation is based on aggregated pressure layers and ecosystem components and the sensitivity scores linking these datasets. All these layers have the same values (scale 0-1) in the beginning. This means that all the aggregated pressure layers have equal impact, e.g. hunting of seals is considered to have the same impact than physical loss. 

For the updated version of BSII the aggregated pressure layers would be preferred to be ranked relative to each other in order to get more realistic and harmonized intensity distribution of pressures. In addition to relative comparison, the ranking should reflect the spatial extent of layers; if extent is overestimated the weighting factor should be smaller. This in practice means that each dataset will be given a weighting factor to scale the pressure down if it is overestimated. The weighting is similar to what was done when aggregating human activities datasets to the pressure layer on physical disturbance (supplementary report on cumulative impacts table 2.)

The process will include following steps.

-          The secretariat will draft the initial weighting factors for the aggregated pressure layers based on literature and observations from the end result of the BSII

-          A table with weighting factors and reasoning for the conclusions will be produced

-          A separate workspace will be established for comments and discussion and an online workshop will be held to make a decision of the final weighting factors

Initial weighting factors produced by the Secretariat

HELCOM Secretariat have produced the initial weighting factors and they can be found in the excel file under documents in this workspace. In the excel file on the left is the name of the layer and the link to corresponding map in the HELCOM map and data service. In the map and data service the metadata of each layer can be accessed by clicking the icon right of the layer name. Suggestion for a weighting value and reasoning can be found on the next colum​ns. Reasoning reflects mostly the spatial extent of the layers and the quality and confidence of the underlying datasets. Four last columns are providing statistical information of each layer. Column D is describing the extent of the layer by indicating the amount of BSII grid cells (1x1km) that are occupied with a value greater than 0. Column E indicates the percentage of occupied cells in the whole dataset. Column F is indicating the mean pressure value of individual dataset (only values greater than 0 included). Finally column G is indicating the sum value of all pressure values summed together.

How to comment the initial weighting values

Commenting and sharing suggestions on the values are done by uploading an excel file to the workspace. The original excel file including the initial values can be downloaded from the workspace located on the right side of the page. Please provide comments and suggestions to the excel file and submit it to the workspace. Please add your initials to the end of the document to separate it from the original and other submissions. Each expert will provide an individual excel file.

I kindly ask you to submit comments before 30 November 2017. The Secretariat will compile a summary of suggestion for the online workshop held 7 December 2017. ​

​In case of any questions please do not hesitate to contact Thank you. 

Outcome of the BSII APL weighting workshop.pdf
13/12/2017 15:19Juuso Haapaniemi
Weighting factor compiled.xlsx
04/12/2017 10:42Juuso Haapaniemi
Weighting factor MS.xlsx
15/11/2017 14:36Matti Sahla
Weighting factor.xlsx
03/11/2017 12:54Juuso Haapaniemi
Weighting factor_CFN.xlsx
01/12/2017 16:08Christina Fevejle Nielsen
Weighting factor_GER.xlsx
30/11/2017 21:34Juliane Wendt
Weighting factor_SK.xlsx
16/11/2017 12:58Samuli Korpinen