Generate Line Overlay
Calculates and returns an overlay of contour lines for the current height map.
generate_line_overlay( geometry, extent, heightmap = NULL, width = NA, height = NA, color = "black", linewidth = 1, lty = 1, data_column_width = NULL, offset = c(0, 0) )
geometry |
An 'sf' object with LINESTRING geometry. |
extent |
A 'raster::Extent' object with the bounding box for the height map used to generate the original map. |
heightmap |
Default 'NULL'. The original height map. Pass this in to extract the dimensions of the resulting overlay automatically. |
width |
Default 'NA'. Width of the resulting overlay. Default the same dimensions as height map. |
height |
Default 'NA'. Width of the resulting overlay. Default the same dimensions as height map. |
color |
Default 'black'. Color of the lines. |
linewidth |
Default '1'. Line width. |
lty |
Default '1'. Line type. '1' is solid, '2' is dashed, '3' is dotted,'4' is dot-dash, '5' is long dash, and '6' is dash-long-dash. |
data_column_width |
Default 'NULL'. The numeric column to map the width to. The maximum width will be the value specified in 'linewidth'. |
offset |
Default 'c(0,0)'. Horizontal and vertical offset to apply to the line, in units of 'geometry'. |
Semi-transparent overlay with contours.
#Add the included `sf` object with roads to the montereybay dataset
#Only run these examples if the `magick` package is installed.
if ("magick" %in% rownames(utils::installed.packages())) {
water_palette = colorRampPalette(c("darkblue", "dodgerblue", "lightblue"))(200)
bathy_hs = height_shade(montereybay, texture = water_palette)
montereybay %>%
height_shade() %>%
add_overlay(generate_altitude_overlay(bathy_hs, montereybay, 0, 0)) %>%
add_overlay(generate_line_overlay(monterey_roads_sf,
attr(montereybay,"extent"), heightmap = montereybay)) %>%
add_shadow(ray_shade(montereybay,zscale=50),0.3) %>%
plot_map()
#Change the line width, color, and transparency
montereybay %>%
height_shade() %>%
add_overlay(generate_altitude_overlay(bathy_hs, montereybay, 0, 0)) %>%
add_overlay(generate_line_overlay(monterey_roads_sf, linewidth=3, color="white",
attr(montereybay,"extent"), heightmap = montereybay),
alphalayer=0.8) %>%
add_shadow(ray_shade(montereybay,zscale=50),0.3) %>%
plot_map()
#Manually specify the width and height to improve visual quality of the lines
montereybay %>%
height_shade() %>%
add_overlay(generate_altitude_overlay(bathy_hs, montereybay, 0, 0)) %>%
add_shadow(ray_shade(montereybay,zscale=50),0.3) %>%
add_overlay(generate_line_overlay(monterey_roads_sf, linewidth=3, color="white",
attr(montereybay,"extent"), width = 1080, height = 1080),
alphalayer=0.8) %>%
plot_map()
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