R: Generate Line Overlay

generate_line_overlay {rayshader} | R Documentation

## Generate Line Overlay

### Description

Calculates and returns an overlay of contour lines for the current height map.

### Usage

    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)
    )

### Arguments

`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'.

### Value

Semi-transparent overlay with contours.

### Examples

    #Add the included `sf` object with roads to the montereybay dataset

    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()

[Package rayshader version 0.24.5 Index]