ursa (version 3.10.4)

global operator: Extract certains statistics for whole image

Description

Function from this global.FUN list returns required statistics FUN for the whole image.

Usage

global_mean(x, ursa = FALSE, ...)
global_median(x, ursa = FALSE, ...)
global_sd(x, ursa = FALSE, ...)
global_sum(x, ursa = FALSE, ...)
global_min(x, ursa = FALSE, ...)
global_max(x, ursa = FALSE, ...)
global_n(x, ursa = FALSE, ...)
global_nNA(x, ursa = FALSE, ...)
global_range(x, ursa = FALSE, ...)
global_quantile(x, ursa = FALSE, ...)

Value

If ursa=FALSE then numeric.

If ursa=TRUE then object of class ursaRaster.

Arguments

x

Object of class ursaRaster.

ursa

Logical. The class of returned value. If FALSE then numeric vector of length one is returned (for global_range vector has length two). If TRUE then returned value is single-band raster image (two-bands image for global_range) with constant value for all cells (blank image). Default is FALSE.

...

Arguments in function global.FUN which are passed to function FUN.

Author

Nikita Platonov

Details

For any function global.FUN, if argument na.rm is not in ..., then FUN is called with forced na.rm=TRUE.

global_range\emph{list of arguments} is implemented as c(global_min(list of arguments), global_max(list of arguments)) with the same list of arguments.

Alternative method to get global statistics is function applying directly to the raster value. For example, sd(ursa_value(x,na.rm=TRUE)). This way is also appropriate for missing global functions: for example, var(ursa_value(x,na.rm=TRUE)).

Examples

session_grid(NULL)
a <- ursa_dummy(2,min=-40,max=80)
a[a<0] <- NA
print(a)
a.mean <- global_mean(a)
a.sd <- global_sd(a)
a.sum <- global_sum(a)
a.min <- global_min(a)
a.max <- global_max(a)
a.median <- global_median(a)
print(c(mean=a.mean,sd=a.sd,sum=a.sum,min=a.min,max=a.max,median=a.median))
v.max <- max(ursa_value(a),na.rm=TRUE)
print(c('global_max()'=a.max,'max(ursa_value())'=v.max,dif=a.max-v.max))
r.max <- global_max(a,ursa=TRUE)
print(r.max)
b <- c(a,'appended scalar value'=a.max)
print(b)
print(global_quantile(a))