Retrieve image metadata

Usage

find_photos(x, year = NULL, color = c("P", "C", "IR", "IRC"), oblique = FALSE)

Arguments

x: Object of class sf or sfc
year: integer; multiple years can be set with vector c(1980, 1990) or range 1980:2990. If NULL all years available are returned
color: character; One or many of "P" (classic photo), "C" (color, rgb image), "IR" (infra-red) or "IRC" (infra-red color). All by default.
oblique: logical; FALSE for vertical aerial photos (camera pointing straight down), TRUE for oblique photos. Use NA or NULL to retrieve both type.

Value

sf with photo extent and metadata

Details

By default, get_image_metadata retrieve photo extent. Centroid of photo are contained in the dataset as the form of x_3857, y_3857. To leverage them you can replace actual geometry with this one. See @examples.

Examples

if (FALSE) { # \dontrun{
library(sf)
x <- read_sf(system.file("extdata/penmarch.shp", package = "happign"))
images_metadata <- find_photos(x, year = 1969)

# Access centroids
centroid <- st_as_sf(
  st_drop_geometry(images_metadata),
  coords = c("x_3857", "y_3857"),
  crs = st_crs(3857)
)
centroid <- st_transform(centroid, 4326)

plot(
  st_geometry(images_metadata[1,]),
  col = "grey80", border = "grey60",
  main = "Photo footprint and centroid"
 )
plot(st_geometry(centroid[1,]), col = "blue", pch = 20, add = TRUE)
plot(st_geometry(x), col = "red", add = TRUE)
} # }