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Please see Appendix 1 for the details of the algorithm implemented in this tool.
Before Before running the tool, it is assumed that the following three layers are already uploaded into AccessMod and that all of them have the same projection system, extent and resolution than the DEM :
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- The population distribution grid (“total population“) is first masked with the landcover merge grid in order to extract the population outside of the barriers, which gives a “partial population” grid, whose sum of pixels values gives the “partial population”.
- The ratio between total and partial population is computed.
- The “partial population” grid is multiplied by this ratio. This process produces a “corrected population“ grid that has no population in barrier pixels, but whose sum of population is equal to the sum of population of the original population distribution grid.
These These three steps are done for each administrative unit found in the input administrative boundaries shapefile. It is therefore recommended to use administrative level 3 or 4 (rather than 1 or 2) so that the population on barriers will be redistributed close to the barriers within a small administrative unit.
The The panel for this tool and its functionalities is as follow:
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(2) “Select merged land cover layer (raster)”, select the raster format layer containing the merged land cover resulting from the use of the first tool (see Section 5.5.2) - named "land cover merged"
(3) Under “Select zone name (text)", select the field from the zone boundaries layer
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