View source: R/addRasterLegend.R
addRasterLegend | R Documentation |
Adds a legend to an existing raster plot, with some additional manual controls.
addRasterLegend( r, direction, side, location = "right", nTicks = 2, adj = NULL, shortFrac = 0.02, longFrac = 0.3, axisOffset = 0, border = TRUE, ramp = "terrain", isInteger = "auto", ncolors = 64, breaks = NULL, minmax = NULL, locs = NULL, cex.axis = 0.8, labelDist = 0.7, minDigits = 2, ... )
r |
the |
direction |
direction of color ramp. If omitted, then direction is automatically
inferred, otherwise can be specified as |
side |
side for tick marks, see |
location |
either a location name (see |
nTicks |
number of tick marks, besides min and max. |
adj |
if location is top, left, bottom or right, use this argument to adjust the location of the legend, defined in percent of the figure width. See Details for additional information. |
shortFrac |
Percent of the plot width range that will be used as the short dimention of the legend. Only applies to preset location options. |
longFrac |
Percent of the plot width range that will be used as the long dimention of the legend. Only applies to preset location options. |
axisOffset |
distance from color bar for labels, as a percent of the plot width. |
border |
logical, should the color legend have a black border |
ramp |
either a vector of color names that will be interpolated, or a color ramp
function that takes an integer (see for example |
isInteger |
If |
ncolors |
grain size of color ramp |
breaks |
If a custom set of color breaks were used in plotting the raster, pass those color breaks here. This overrides the minmax option. |
minmax |
min and max values from which the color ramp will be derived. If left
as |
locs |
locations of tick marks, if |
cex.axis |
size of axis labels |
labelDist |
distance from axis to axis labels (passed to |
minDigits |
minimum number of significant digits for labels |
... |
additional parameters to be passed to |
A number of predefined locations exist in this function to make it easy to
add a legend to a raster plot.
Preset locations
are: topleft
, topright
, bottomleft
,
bottomright
, left
, right
, top
and bottom
.
If more fine-tuned control is desired, then a numeric vector of length 4 can be
supplied to location
, specifying the min x, max x, min y and max y
values for the legend.
Additionally, the adj
argument can be used to more intuitively adjust
where the legend is placed. adj
is defined as a percentage of the
figure width or height, left to right, or bottom to top, respectively. For
example, if the legend is at the bottom, adj = 0.8
will place the
legend 80% of the distance from the top of the figure, horizontally centered.
See examples.
Invisibly returns a list with the following components.
coords 2-column matrix of xy coordinates for each color bin in the legend.
width Coordinates for the short dimension of the legend.
pal the color ramp
tickLocs the tick mark locations in plotting units
Pascal Title
library(raster) r <- raster(system.file("external/test.grd", package="raster")) plot(r, legend = FALSE) addRasterLegend(r, location = 'right') addRasterLegend(r, location = 'top') #fine-tune placement plot(r, legend = FALSE) addRasterLegend(r, location=c(181000, 181100, 330500, 331500), side = 4)
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