draw_subcatchments_OCN: Draw subcatchment map from an Optimal Channel Network
In OCNet: Optimal Channel Networks

draw_subcatchments_OCN

R Documentation

Draw subcatchment map from an Optimal Channel Network

Description

Function that draws a map of subcatchments generated by the aggregation process on the OCN. If theme is NULL, colormap is such that neighbouring subcatchments have distinguished colors. If theme is specified, colors reflect the values of theme across subcatchments, in analogy with draw_thematic_OCN.

Usage

draw_subcatchments_OCN(OCN, theme = NULL, drawRiver = TRUE,
 colPalette = NULL, colLevels = NULL, riverColor = NULL, addLegend = NULL, 
 min_lwd = 0.5, max_lwd = 5, add = FALSE, args_imagePlot = list(), ...)

Arguments

`OCN`	A `river` object as produced by `aggregate_OCN`.
`theme`	Vector (of length `OCN$SC$Nnodes` expressing the spatial field of interest.
`drawRiver`	Logical. If `TRUE`, draw the OCN on top of the subcatchment map.
`colPalette`	Color palette used. `colPalette` accepts both functions creating color palettes and vectors of colors. In the latter case, `length(colPalette)` must be greater than the number of color levels. If `theme = NULL`, default is `c("#009900", "#FFFF00", "#FF9900", "#FF0000", "#FF00FF", "#9900CC", "#555555", "#BBBBBB")`. Only the first `n` colors are used, where `n` is the number of different colors needed (calculated via a greedy coloring algorithm). `colPalette` accepts both functions creating color palettes and vectors of colors (see examples); in the latter case, the length of the vector cannot be lower than `n` (`n` cannot be predicted a priori, but generally 6 colors should suffice). If `theme != NULL`, default is `colorRampPalette(c("yellow","red","black"))`.
`colLevels`	Number of colors in the palette (only effective if `theme` is not null). `colLevels` must be a vector of the form `c(minval, maxval)` or `c(minval, maxval, N_levels)`. The vector of breakpoints used to attribute `theme` values to a given color is then defined as `seq(minval, maxval, N_levels)`. Default is `minval = min(theme[!(is.nan(theme))])`, `maxval = max(theme[!(is.nan(theme))])`, `N_levels = 1000`.
`riverColor`	Color used to display the OCN (only effective if `drawRiver = TRUE`).
`addLegend`	Logical. State if a legend should be displayed (only active if `theme` is not null.
`min_lwd`, `max_lwd`	Minimum and maximum values of line width used to display the OCN (actual line width is proportional to the square root of drainage area).
`add`	Logical. If `TRUE`, add to an already existing plot. Taken as `FALSE` (with a warning if a different value is supplied) if no graphics device is open.
`args_imagePlot`	Only effective if `addLegend = TRUE`. List of arguments passed to `imagePlot` for drawing a continuous legend. For example, argument `smallplot` can be used to specify the plot coordinates for the legend.
`...`	Further arguments to be passed to `image`. Default plot options are as in `draw_thematic_OCN`.

Value

No output is returned.

Examples

# 1a) aggregate a 20x20 OCN , use thrA = 5 pixels
# and draw subcatchments with default color palette
OCN <- aggregate_OCN(landscape_OCN(OCN_20), thrA = 5)
draw_subcatchments_OCN(OCN, drawRiver = TRUE)

# 1b) same as above, but define color palette with a function
draw_subcatchments_OCN(OCN, drawRiver = TRUE, colPalette = rainbow)

# 1c) same as above, but define color palette with a vector of colors
draw_subcatchments_OCN(OCN, drawRiver = TRUE, colPalette = hcl.colors(6, "Dark 3"))

# 2) Display theme at subcatchment level
draw_subcatchments_OCN(OCN, theme = OCN$AG$A)

OCNet documentation built on Sept. 12, 2025, 10:19 a.m.