hyperSpec (version 0.98-20150304)

makeraster: makeraster

Description

find an evenly spaced grid for x

Usage

makeraster(x, startx, d, newlevels, tol = 0.1)
fitraster(x, tol = 0.1)

Arguments

x

numeric to be fitted with a raster

startx

starting point ("origin") for calculation of the raster

d

step size of the raster

newlevels

levels of the raster

tol

tolerance for rounding to new levels: elements of x within tol of the distance between the levels of the new grid are rounded to the new grid point.

Value

list with elements

x

the values of x, possibly rounded to the raster values

levels

the values of the raster

Details

makeraster fits the data to the specified raster.

fitraster tries different raster parameter and returns the raster that covers most of the x values: The differences between the values of x are calculated (possible step sizes). For each of those step sizes, different points are tried (until all points have been covered by a raster) and the parameter combination leading to the best coverage (i.e. most points on the grid) ist used.

Note that only differences between the sorted values of x are considered as step size.

Examples

x <- c (sample (1:20, 10), (0 : 5) + 0.5)
raster <- makeraster (x, x [1], 2)
raster
plot (x)
abline (h = raster$levels, col = "#00000040")

## unoccupied levels
missing <- setdiff (raster$levels, raster$x)
abline (h = missing, col = "red")

## points acutally on the raster
onraster <- raster$x %in% raster$levels
points (which (onraster), raster$x [onraster], col = "blue", pch = 20)
raster <- fitraster (x)
raster
plot (x)
abline (h = raster$levels, col = "#00000040")

## unoccupied levels
missing <- setdiff (raster$levels, raster$x)
abline (h = missing, col = "red")

## points acutally on the raster
onraster <- raster$x %in% raster$levels
points (which (onraster), raster$x [onraster], col = "blue", pch = 20)

x <- c (sample (1:20, 10), (0 : 5) + 0.45)
raster <- fitraster (x)
raster
plot (x)
abline (h = raster$levels, col = "#00000040")

## unoccupied levels
missing <- setdiff (raster$levels, raster$x)
abline (h = missing, col = "red")

## points acutally on the raster
onraster <- raster$x %in% raster$levels
points (which (onraster), raster$x [onraster], col = "blue", pch = 20)