For each pair of photos whose footprints intersect, computes the overlap area and the percentage of each photo's footprint that overlaps. Most useful on same-scale photos from the same flight.
Value
A tibble with columns photo_a, photo_b, overlap_km2,
pct_of_a, and pct_of_b. Only pairs with non-zero overlap are returned.
Details
Overlap percentages are estimates based on flat-terrain footprints from
fly_footprint(). See that function for details on terrain limitations.
Examples
centroids <- sf::st_read(system.file("testdata/photo_centroids.gpkg", package = "fly"))
#> Reading layer `photo_centroids' from data source
#> `/home/runner/work/_temp/Library/fly/testdata/photo_centroids.gpkg'
#> using driver `GPKG'
#> Simple feature collection with 20 features and 9 fields
#> Geometry type: POINT
#> Dimension: XY
#> Bounding box: xmin: -126.7631 ymin: 54.34512 xmax: -126.449 ymax: 54.47635
#> Geodetic CRS: WGS 84
aoi <- sf::st_read(system.file("testdata/aoi.gpkg", package = "fly"))
#> Reading layer `aoi' from data source
#> `/home/runner/work/_temp/Library/fly/testdata/aoi.gpkg' using driver `GPKG'
#> Simple feature collection with 1 feature and 0 fields
#> Geometry type: MULTIPOLYGON
#> Dimension: XY
#> Bounding box: xmin: -126.75 ymin: 54.34813 xmax: -126.45 ymax: 54.47
#> Geodetic CRS: WGS 84
photos_12k <- centroids[centroids$scale == "1:12000", ]
selected <- fly_select(photos_12k, aoi, mode = "all")
#> Spherical geometry (s2) switched off
#> although coordinates are longitude/latitude, st_union assumes that they are
#> planar
#> although coordinates are longitude/latitude, st_intersects assumes that they
#> are planar
#> Selected 10 of 10 photos intersecting the AOI
#> Spherical geometry (s2) switched on
fly_overlap(selected)
#> Spherical geometry (s2) switched off
#> Spherical geometry (s2) switched on
#> # A tibble: 7 × 5
#> photo_a photo_b overlap_km2 pct_of_a pct_of_b
#> <int> <int> <dbl> <dbl> <dbl>
#> 1 699370 699365 2.05 27.2 27.2
#> 2 699370 699373 0.134 1.8 1.8
#> 3 699426 699425 3.92 52.1 52.1
#> 4 699396 699393 0.246 3.3 3.3
#> 5 699396 699421 1.5 19.9 19.9
#> 6 699419 699421 1.46 19.4 19.4
#> 7 699425 699393 0.676 9 9