The Human Footprint (HF) of the Northern Appalachian/Acadian ecoregion measures the extent and relative intensity of human influence on terrestrial ecosystems at a resolution of 90 m using best available data sets on human settlement (population density, dwelling density, urban areas), access (roads, rail lines), landscape transformation (landuse/landcover, dams, mines, watersheds), and electrical power infrastructure (utility corridors).
Each 90m grid cell is attributed with a Human Footprint score between 0 and 100, where 0 represents minimum human influence and 100 represents maximum human influence at that location. The Human Footprint scores (0-100) may be interpreted as the percent influence.
The Human Footprint is calculated by assigning Human Influence (HI) scores of 0 to 10 to geographic data layers that map features of human activity. Where 0 is no human influence (no conversion from natural state) and 10 is maximum human influence (complete conversion e.g. urban areas, road surfaces). HI scores from assigned to data layers are combined together to calculate the Human Influence Index (HII), that measures total direct human impact.
The Human Footprint is a relative measure of human impact - relative to the ecological context. The Human Footprint is calculated by normalizing the Human Influence Index (HII) within ecological subunits within the study area using the equation HFi = [(HIIi - HIImin_j) * 100] / (HIImax_j - HIImin_j) where i represents the cell and j represents the ecologic subunit of which the cell is a member.