diff --git a/R/raster_to_clean_polygon.R b/R/raster_to_clean_polygon.R new file mode 100644 index 0000000..a3bd517 --- /dev/null +++ b/R/raster_to_clean_polygon.R @@ -0,0 +1,93 @@ +# SCRIPT TO POLYGONIZE, CLEAN, and SMOOTH RASTER OUTPUT (in tiles) +# To do: add functionnality to stitch tiles using "summarize" +# To do: compare smoothing results + +# *****REQUIRES DEV VERSION OF STARS**** devtools::install_github("r-spatial/stars") + +library(smoothr) +library(dplyr) +library(stars) +library(sf) + +#### RASTER TO POLYGON FUNCTION #### + +# READ CLASSIFIED RASTER + r <- stars::read_stars('data/out/3CategoryPrediction/20190926-103025_map_recl.tif', proxy = F) + d <- st_dimensions(r) + int <- 1000 + x_seq <- seq(d$x$from,d$x$to+int,int) + +# CLEANING FUNCTION (PER TILE) + ras_to_clean_pol <- function(seq_along = 1, + out_folder = "data/clean/", + out_format = "kml", + wetland_class_number = c(2), + min_area_drop_m2 = 625 * 4, + max_area_fill_m2 = 625 * 4, + raw_out = F, + clean_out = F, + smooth_out = T, + smooth_method = "chaikin", + return = T + ){ + + write.csv("", paste0(out_folder,seq_along,"_start.txt")) + # CLIP MY TILE + my_tile <- r[1,x_seq[seq_along]:x_seq[seq_along+1],] %>% st_as_stars() + # print("ok subset") + + # POLYGONIZE (AND DISSOLVE/MERGE BY CLASS) + p <- sf::st_as_sf(my_tile, + as_points = F, + merge = T) + # print("ok poly") + + # RENAME FIELDS + names(p) <- c("class","geometry") + + # SELECT WETLANDS OF INTEREST + p <- p %>% + filter(class %in% wetland_class_number) + + # CALCULATE AREA (m2) (based on trim 25x25 data, so 625 m2 is one pixel) + p <- p %>% + mutate(area = st_area(.)) + # print("ok area") + + if(raw_out == T){ + write_sf(p, paste0(out_folder,seq_along,"_raw.",out_format)) + # print("ok raw") + } + + # FILTER AREA (i.e. DROP CRUMBS) + p <- p %>% + filter(area > units::as_units(min_area_drop_m2, "m2")) + # print("ok crumbs") + + # FILL HOLES + p <- p %>% + fill_holes(threshold = units::as_units(max_area_fill_m2, "m2")) + # print("ok holes") + + # WRITE CLEAN + if(clean_out == T){ + write_sf(p, paste0(out_folder,seq_along,"_clean.",out_format)) + # print("ok clean") + } + + # SMOOTH POLYGONS + if(smooth_out == T){ + p_sm <- smooth(p, method = smooth_method) + write_sf(p_sm, paste0(out_folder,seq_along,"_smooth.",out_format)) + # print("ok smooth") + } + + if(return == "clean"){ + return(p) + } + if(return == "smooth"){ + return(p_sm) + } + } + +pol <- do.call(rbind, lapply(1:length(x_seq), ras_to_clean_pol))