Make a neat header image

I made a pretty neat header image for this site using raster data from my Square Lake Master Plan Update project.

library(sf)
library(ggplot2)
library(dplyr)
library(Cairo)

Download regional park geography from Minnesota Geospatial Commons.

## base geometries -------------------------------------------------------------
temp <- tempfile()
download.file("ftp://ftp.gisdata.mn.gov/pub/gdrs/data/pub/us_mn_state_metc/plan_parks_regional/gpkg_plan_parks_regional.zip",
  destfile = temp
)

square_lake <- sf::read_sf(unzip(temp, "plan_parks_regional.gpkg")) %>%
  filter(STATUS == "Existing") %>%
  filter(PARKNAME == "Square Lake") %>%
  group_by(PARKNAME, AGENCY) %>%
  sf::st_union() %>%
  st_as_sf() %>%
  st_transform(4326)

fs::file_delete("plan_parks_regional.gpkg")

I refined contours.RDS in my previous project. The data come from MnTOPO, a web application for viewing, printing and downloading high-resolution elevation data for the State of Minnesota that was collected using LiDAR technology. I only needed data from a small area, so I drew a polygon over my study area using MnTOPO.

# load 3 meter contours over the Square Lake area

contour <- readRDS("contours.RDS") %>%
  st_transform(4326) %>%
  sf::st_crop(xmin = -92.7854633,
              ymin = 45.1497518,
              xmax = -92.8007197,
              ymax = 45.1568488)

Generate plot with {ggplot2}.

ggplot() +
  geom_sf(
      data = contour,
      color = "gray75",
      lwd = 0.2
    ) +
  theme_void()

Finally, save the plot as a PDF and open it in Adobe Illustrator for modifications.

Cairo::CairoPDF(file = "contours.pdf", 
                onefile = TRUE, width = 12, height = 10, bg = "transparent")
ggplot() +
  geom_sf(
      data = contour,
      color = "gray75",
      lwd = 0.2
    ) +
  theme_void()
dev.off()

I adjusted the background and finessed the positioning so it would display like I wanted it to on my home page. Here is the final product.