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My question is about how to save a ggplot2 graph in respect with the aspect ratio. If I make a simple graphic and set the dimension of the plot with ggsave(), the plot will occupy the entire area of the saved file.

library(ggplot2) library(sf) #> Linking to GEOS 3.7.1, GDAL 2.4.2, PROJ 5.2.0 #> WARNING: different compile-time and runtime versions for GEOS found: #> Linked against: 3.7.1-CAPI-1.11.1 27a5e771 compiled against: 3.7.0-CAPI-1.11.0 #> It is probably a good idea to reinstall sf, and maybe rgeos and rgdal too df <- data.frame( longitude = -47, latitude = 45 ) p <- ggplot(df, aes(x = longitude, y = latitude)) + geom_point() + theme( plot.background = element_rect(fill = "black") ) tf <- tempfile(fileext = ".png") ggsave(tf, p, width = 4, height = 4) p

In the following example, I transform the data into an sf object and plot it using geom_sf() This cause the plot to have a certain aspect ratio to match the chosen projection.

df <- st_as_sf(df, coords = c("longitude", "latitude"), crs = 4326) p <- ggplot(df) + geom_sf() + theme( plot.background = element_rect(fill = "black") ) tf <- tempfile(fileext = ".png")

However, setting the dimensions to 4 x 4 will cause paddings (white borders) to appear on the side of the plot. Hence, these white borders will be present when the graph is pasted into a PowerPoint presentation (for example).

ggsave(tf, p, width = 4, height = 4) p

You can open tf and see the white padding around the black area. My question is about, how can I find the correct aspect ratio of the plot so I can provide appropriate dimensions to ggsave().

# Which dimensions to use to respect the aspect ratio of the map? # ggsave(tf, p, width = xxx, height = yyy)

Created on 2019-11-28 by the reprex package (v0.3.0)

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Since I'm working in png, instead I used a hint about package magick (apologies but I've lost the link). In passing, this also adds a logo in the top left.

library(tidyverse) library(magick) # filename, based on subtitle in my case, but you could use title gg_file <- paste0("graphs/", last_plot()$labels$subtitle,".png") # save with known width and unknown height # without an annoying message about the size used suppressMessages(ggsave(gg_file, plot = last_plot(), width = 20, units = "cm")) # remove whitespace in this png # and add a little back to make room for a logo # and to stop it looking too squashed # you did also want a logo? mine is about 100 pixels square m_png <- image_border(image_trim(image_read(gg_file)), "white", "30x30") m_logo <- image_composite(m_png, logo %>% image_scale("120")) image_write(m_logo, gg_file)
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Here is my solution to remove borders around ggplot2 graphs: https://www.pmassicotte.com/post/removing-borders-around-ggplot2-graphs/

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Unfortunately, this link is not working for me - looks like the url changed. New link (assuming this is the same post you shared originally): pmassicotte.com/posts/…

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