colorize  R Documentation 
colorize
assigns color table to raster image.
colorize(obj, value = NULL, breakvalue = NULL, name = NULL, pal = NULL, inv = NA, stretch = c("default", "linear", "equal", "mean", "positive", "negative", "diff", "category", "julian", "date", "time", "slope", "conc", "sd", "significance", "bathy", "grayscale", "greyscale", ".onetoone"), minvalue = NA, maxvalue = NA, byvalue = NA, ltail = NA, rtail = NA, tail = NA, ncolor = NA, nbreak = NA, interval = 0L, ramp = TRUE, byte = FALSE, lazyload = FALSE, reset = FALSE, origin = "19700101" ,format = "", alpha = "", colortable = NULL, verbose = FALSE, ...) palettize(...) ## wrapper for nonspatial vectors
obj 

value 
Numeric. Values to be assigned to categories. 
breakvalue 
Numeric. Values to be assigned to intervals. 
name 
Character. Names of categories. 
pal 
Function or character. If function then value should corresponded to function, which creates a vector of colors. If character then values should correponded to R color names or hexadecimal string of the form "#RRGGBB" or "#RRGGBBAA". 
inv 
Logical. Invert sequence of colors. 
stretch 
Character. Either kind of value transformation ( 
minvalue 
Numeric. Lower range limit. 
maxvalue 
Numeric. Upper range limit. 
byvalue 
Numeric. Increment of the sequence from 
ltail 
Numeric. Partition of omitted values at left tail. 
rtail 
Numeric. Partition of omitted values at right tail. 
tail 
Numeric. Partition of omitted values at both tail. If length of 
ncolor 
Numeric or interer. Number of desired colors (or categories) 
nbreak 
Numeric or interer. Number of desired separators between colors. 
interval 
Integer. How to underwrite categories? Use direct 
ramp 
Logical. Is color ramp required? 
byte 
Logical. Forcing to produce color table for storage in byte format (not more than 255 colors). Default is 
lazyload 
Logical. If 
reset 
Logical. If 
origin 
Character. Origin for 
format 
Character. Format date/time objects for arguments 
alpha 
Character or numeric. The characteristics of transparency. If character, then hexadecimal values between "00" and "FF" are allowed, and then coerced to numeric value between 0 and 255. If numeric, and 
colortable 
Object of class 
verbose 
Logical. Some output in console. Primarily for debug purposes. 
... 
For For 
palettize
is a wrapper ursa_colortable(colorize(...))
to return color table for onedimensional numeric or character vector.
colortable
is designed to prepare pretty thematic maps.
Color rampimg (ramp=TRUE
) is not quick in computatons and has no effective labelling. It is intoduced to visualize nonthematic maps, and it is assumed that labeling can be omitted for such maps.
The labelling implementation is based on some improvements of pretty
function. The notation of intervals is mixed by brackets and comparative symbols, for example: "<=1.5","(1.5,2.5]","(2.5,3.5]",">3.5"
Reserved values for interval
:
0L
or FALSE
 no interlavs. Values are interpreted as category, even if they are in nonnominal scale
1L
or TRUE
 each category corresponds to interval. The low limit of lowest category is Inf
. The high limit of highest category is +Inf
2L
 different implementation of interval=1
. In some cases may relult more pretty labeling.
If breaks
is numerical vector and colors
has zero length, then it is assumed interal scaling, and interval=1L
is assigned to unspecified interval
Finite values of extreme intervals are neccessary sometimes, however this option is not implemented currently
Keywords for stretch
to create predefined color tables:
"positive"
 lower limit is 0. Palette is "Oranges"
"negative"
 higher limit is 0. Palette is "Purples"
"grayscale", "greyscale"
 palette is "Greys". Usually used for raw satellite images.
"mean"
 designed for common thematic maps and for averaged map across set of maps. Palette is "Spectral"
"sd"
 designed for spatial mapping of standard deviation across set of maps. Palette is "YlGnBu"
"diff"
 diverge palette "RdBu". Absolute values of lower and upper limits are equal, zero is in the middle of palette. Designed for anomaly maps.
"slope"
 is similar to diff
but without extreme colors, which are reserved for contouring of statistically significant areas.
"significance"
 desiged to illustrate statistically significant areas of slope.
The realisation is colortable(obj, value=c(0.999, 0.99, 0.95, 0.9, 0.5, +0.5, +0.9, +0.95, +0.99, +0.999), interval=1L, palname="RdBu")
"category"
 Values are interpreted in nominal scale. Palette is based on random colors from "Pairs" palette.
"conc"
 designed for visualization of sea ice concentration data, which have lower limit 0 and higher limit 100. Palette is "Blues"
"bathy"
 designed for ocean depth (bathymetry) maps. Internally colorize(obj, stretch="equal",interval=1L, palname="Blues", inv=TRUE)
is used to detect the crossing from shelf waters to deep water basin. Better practice is to do second step with manual specification of value
argument.
"internal"
 continuous colors, designed for conversion to greyscale with keeping of intensities.
"default"
 allowing to detect stretch by intuition, without any strong mathematical criteria
It is allowed manual correction of labels using followed code example:
names(ursa_colortable(x)) < c("a<=0","0<a<=1","a>1")
Object of class ursaRaster
with named character vector of item $colortable
Nikita Platonov platonov@sevin.ru
ursa_colortable
,
ursa_colortable<
session_grid(NULL) a < pixelsize()350 print(a) b1 < colorize(a,ramp=FALSE) print(ursa_colortable(b1)) b2 < colorize(a,interval=1,stretch="positive",ramp=FALSE) print(ursa_colortable(b2)) b3 < colorize(a,interval=2,stretch="positive",ramp=FALSE) print(ursa_colortable(b3)) b4 < colorize(a,value=c(150,250),interval=1) print(ursa_colortable(b4)) names(ursa_colortable(b4)) < c("x<=150","150<x<=250","x>250") print(ursa_colortable(b4)) display(b4)
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