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This function sets up a depth stratified survey grid. A simple gradient in depth is simulated using spline with a shallow portion, shelf and deep portion. Adding covariance to the depth simulation is an option.
spline
make_grid( x_range = c(-140, 140), y_range = c(-140, 140), res = c(3.5, 3.5), shelf_depth = 200, shelf_width = 100, depth_range = c(0, 1000), n_div = 1, strat_breaks = seq(0, 1000, by = 40), strat_splits = 2, method = "spline" )
Range (min x, max x) in x dimension in km
Range (min y, max y) in y dimension in km
Resolution, in km, of the grid cells
Approximate depth of the shelf in m
Approximate width of the shelf in km
Range (min depth, max depth) in depth in m
Number of divisions to include
Define strata given these depth breaks
Number of times to horizontally split strat (i.e. easy way to increase the number of strata)
Use a "spline", "loess" or "bezier" to generate a smooth gradient or simply use "linear" interpolation?
Returns RasterBrick of the same structure as survey_grid
survey_grid
# NOT RUN { r <- make_grid(res = c(10, 10)) raster::plot(r) p <- raster::rasterToPolygons(r$strat, dissolve = TRUE) sp::plot(p) # }
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