https://github.com/cran/fields
Tip revision: 66561c3c33070df2578182fed373cf04d4a7c1c6 authored by Douglas Nychka on 13 December 2016, 06:57:09 UTC
version 8.7
version 8.7
Tip revision: 66561c3
color.scale.R
# fields is a package for analysis of spatial data written for
# the R software environment .
# Copyright (C) 2016
# University Corporation for Atmospheric Research (UCAR)
# Contact: Douglas Nychka, nychka@ucar.edu,
# National Center for Atmospheric Research, PO Box 3000, Boulder, CO 80307-3000
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with the R software environment if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
# or see http://www.r-project.org/Licenses/GPL-2
color.scale <- function(z, col = tim.colors(256),
zlim = NULL, transparent.color = "white", eps = 1e-08) {
#
# converts real values to a color scale of NC values.
# role of eps is to prevent values exactly at the end of the range from being
# missed
if (is.null(zlim)) {
zlim <- range(z, na.rm = TRUE)
}
z[(z < zlim[1]) | (z > zlim[2])] <- NA
NC <- length(col)
breaks <- seq(zlim[1] * (1 - eps), zlim[2] * (1 + eps), ,
NC + 1)
# the magic of R ...
icolor <- cut(c(z), breaks)@.Data
# returned values is a vector of character hex strings encoding the colors.
ifelse(is.na(icolor), transparent.color, col[icolor])
}