# Edge-Water-Test This function checks if an edge would cross a water or mountain surface. ```r edgeNotValid(grid,point.a, point.b, landwatermask, upperbound) ``` ## Arguments - `grid`: A grid to which the edge should be added if it hits no water or mountain surfaces. - `point.a`: A point in a grid given by its row and column. - `point.b`: A point in a grid given by its row and column. - `landwatermask`: A grid containing the land-water-information of the observed area. If a grid cell containes no land, the value of the cell in the landwatermask is -1, otherwise it is 0. Additional, height-informations could be added for land surfaces. In this case, take care of the 'upperbound' value. - `upperbound`: This value determines the height (based on values in 'landwatermask') which is considered to be a barrier for species distribution. ## Details This function checks if an edge would cross a water or mountain surface. ## Returns A boolean value which determines if the edge would cross a water or mountain surface. ## Author(s) Maximilian Lange, Sven Lautenbach ## Examples ```r ##load data data(dataset.all.species) data(dataset.landwater) ##initialize variables distance <- 5 ##create grid parameters dimension <- getDimension(dataset.all.species) origin <- getOrigin(dataset.all.species) ##create landwatermask landwatermask.nocoast <- createLandwatermask(dataset.landwater, dimension, origin) ##extract datasets of one species out of database dataset.one.species <- extract.species(dataset.all.species, 3) ##create grid grid <- matrix(0,dimension[1],dimension[2]) ##add points grid <- data.into.Grid(dataset.one.species, dimension, origin) ##points to list points <- which(grid > 0) points.xy <- list() for (i in 1:length(points)){ points.xy[[i]] <- c(ifelse((points[i] %% dimension[1]) == 0, dimension[1], points[i] %% dimension[1]), ceiling(points[i]/dimension[1])) } ##Edge-Water-Test check <- edgeNotValid(grid, points.xy[[1]],points.xy[[2]], landwatermask.nocoast, 1000) print(check) ```

edgeNotValid function