Saving Spatial Data From R

• Once we’ve created new spatial objects in R we often want to save them so they can be used later or shared with others
• Let’s start where we left off when cropping data

library(sf)
library(terra)

harv_boundary <- read_sf("data/harv/harv_boundary.shp")
harv_dtm <- rast("data/harv/harv_dtmfull.tif")

bbox <- st_bbox(c(xmin = 731000, ymin = 4713000, xmax = 732000, ymax = 4714000), crs = st_crs(dtm_harv))
harv_dtm_small <- crop(harv_dtm, bbox)
harv_soils_small <- crop(harv_soils, bbox)

Writing raster data

• To save data we use write functions
• So to save the DTM that was cropped to Harvard Forest boundary we use writeRaster
• The first argument is the object we want to write and the second is the file name
• The format of the raster will be determined by the file extension
• To save as geotiff we use .tif

writeRaster(harv_dtm_small, "harv_dtm_small.tif")

• We can see that this worked by reading it back in

rast("harv_dtm_small.tif")

• We can see this is the cropped data because it’s dimensions are < 150 x 150

Writing sf vector data

• To save data sf vector data we use write_sf
• Again the arguments are the object to be written and the name of the file to write to
• With the extension indicating the file type

write_sf(harv_soils_small, "harv_soils_small.shp")

• If we look in the Files tab we can see this created a full set of the files that make up a single shape file

Saving maps

• We can save ggplot maps in the same way we save other ggplots

ggsave("harv_map.png")

Do Tasks 5-6 of Cropping NEON Data.