Non-functional extract of fasterraster usage

bias_shapes.R

bias_matrix <- as.matrix(bias_raster)  # Bias measure
num_matrix <- as.matrix(number_raster) # Number of samples measure
# Boolean matrix for signficant bias
bias_mat2 <- ifelse((bias_matrix > bias_funs$upper(num_matrix)) | bias_matrix < bias_funs$lower(num_matrix), 1, NA) 

 # Convert bias boolean to shapes. This is a list of shapes, each shape being an NX2 matrix of points. 
  bias_shapes <- fasteraster::raster2vector(bias_mat2) %>% 
  # Remove shapes that are actually just points or lines (<= 3 defining points)
  {Filter(function(x) nrow(x) > 3, .) } %>%  
  # Convert matrix coords to lat/long for each shape
    lapply(function(x) cbind(360*x[,2]/ncol(bias_matrix) - 180, -180*x[,1]/nrow(bias_matrix) + 90)) 

# Convert the list of shapes into a Spatial object
z <- seq_along(bias_shapes)
bias_p <- SpatialPolygons(lapply(z, function(z) Polygons(list(Polygon(bias_shapes[[z]])), z)), proj4string = CRS(proj4string(bias_raster)))