points package:graphics R Documentation _A_d_d _P_o_i_n_t_s _t_o _a _P_l_o_t _D_e_s_c_r_i_p_t_i_o_n: 'points' is a generic function to draw a sequence of points at the specified coordinates. The specified character(s) are plotted, centered at the coordinates. _U_s_a_g_e: points(x, ...) ## Default S3 method: points(x, y = NULL, type = "p", ...) _A_r_g_u_m_e_n_t_s: x, y: coordinate vectors of points to plot. type: character indicating the type of plotting; actually any of the 'type's as in 'plot.default'. ...: Further graphical parameters may also be supplied as arguments. See 'Details'. _D_e_t_a_i_l_s: The coordinates can be passed in a plotting structure (a list with 'x' and 'y' components), a two-column matrix, a time series, .... See 'xy.coords'. If supplied separately, they must be of the same length. Graphical parameters commonly used are '_p_c_h' plotting 'character', i.e., symbol to use. This can either be a single character or an integer code for one of a set of graphics symbols. The full set of S symbols is available with 'pch=0:18', see the examples below. Value 'pch="."' (equivalently 'pch = 46') is handled specially. It is a rectangle of side 0.01 inch (scaled by 'cex'). In addition, if 'cex = 1' (the default), each side is at least one pixel (1/72 inch on the 'pdf', 'postscript' and 'xfig' devices). For other text symbols, 'cex = 1' corresponds to the default fontsize of the device, often specified by an argument 'pointsize'. For 'pch' in '0:25' the default size is about 75% of the character height (see 'par("cin")'). '_c_o_l' color code or name, see 'par'. '_b_g' background (fill) color for the open plot symbols given by 'pch=21:25'. '_c_e_x' character (or symbol) expansion: a numerical vector. This works as a multiple of 'par("cex")'. '_l_w_d' line width for drawing symbols see 'par'. Others less commonly used are 'lty' and 'lwd' for types such as '"b"' and '"l"'. Graphical parameters 'pch', 'col', 'bg', 'cex' and 'lwd' can be vectors (which will be recycled as needed) giving a value for each point plotted. If lines are to be plotted (e.g. for 'type = "b"'/ the first element of 'lwd' is used. Points whose 'x', 'y', 'pch', 'col' or 'cex' value is 'NA' are omitted from the plot. '_p_c_h' _v_a_l_u_e_s: Values of 'pch' are stored internally as integers. The interpretation is * 'NA_integer_': no symbol. * '0:18': S-compatible vector symbols. * '19:25': further R vector symbols. * '26:31': unused (and ignored). * '32:127': ASCII characters. * '128:255' native characters _only in a single-byte locale and for the symbol font_. ('128:159' are only used on Windows.) * '-32 ...' Unicode point (where supported). Note that unlike S (which uses octagons), symbols '1', '10', '13' and '16' use circles. The filled shapes '15:18' do not include a border. The following R plotting symbols are can be obtained with 'pch=19:25': those with '21:25' can be colored and filled with different colors: 'col' gives the border color and 'bg' the background color. * 'pch=19': solid circle, * 'pch=20': bullet (smaller solid circle, 2/3 the size of 19), * 'pch=21': filled circle, * 'pch=22': filled square, * 'pch=23': filled diamond, * 'pch=24': filled triangle point-up, * 'pch=25': filled triangle point down. Note that all of these both fill the shape and draw a border. Some care in interpretation is needed when semi-transparent colours are used for both fill and border (and the result might be device-specific and even viewer-specific for 'pdf'). The difference between 'pch=16' and 'pch=19' is that the latter uses a border and so is perceptibly larger when 'lty' is large relative to 'cex'. Values 'pch=26:31' are currently unused and 'pch=32:127' give the ASCII characters. In a single-byte locale 'pch=128:255' give the corresponding character (if any) in the locale's character set. Where supported by the OS, negative values specify a Unicode point, so e.g. '-0x2642L' is a 'male sign' and '-0x20ACL' is the Euro. A character string consisting of a single character is converted to an integer: '32:127' for ASCII characters, and usually to the Unicode point number otherwise. (In non-Latin-1 single-byte locales, '128:255' will be used for 8-bit characters.) If 'pch' supplied is a logical, integer or character 'NA' or an empty character string the point is omitted from the plot. If 'pch' is 'NULL' or otherwise of length 0, 'par("pch")' is used. If the symbol font ('par(font = 5)') is used, numerical values should be used for 'pch': the range is 'c(32:126, 160:254)' in all locales (but '240' is not defined (used for 'apple' on Mac OS) and '160', Euro, may not be present). _N_o_t_e: A single-byte encoding may include the characters in 'pch=128:255', and if it does, a font may not include all (or even any) of them. Not all negative numbers are valid as Unicode points, and no check is done. A display device is likely to use a rectangle for (or omit) Unicode points that do not exist or which it does not have a glyph. _R_e_f_e_r_e_n_c_e_s: Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) _The New S Language_. Wadsworth & Brooks/Cole. _S_e_e _A_l_s_o: 'plot', 'lines', and the underlying workhorse function 'plot.xy'. _E_x_a_m_p_l_e_s: require(stats) # for rnorm plot(-4:4, -4:4, type = "n")# setting up coord. system points(rnorm(200), rnorm(200), col = "red") points(rnorm(100)/2, rnorm(100)/2, col = "blue", cex = 1.5) op <- par(bg = "light blue") x <- seq(0,2*pi, len=51) ## something "between type='b' and type='o'": plot(x, sin(x), type="o", pch=21, bg=par("bg"), col = "blue", cex=.6, main='plot(..., type="o", pch=21, bg=par("bg"))') par(op) ##-------- Showing all the extra & some char graphics symbols --------- pchShow <- function(extras = c("*",".", "o","O","0","+","-","|","%","#"), cex = 3, ## good for both .Device=="postscript" and "x11" col = "red3", bg = "gold", coltext = "brown", cextext = 1.2, main = paste("plot symbols : points (... pch = *, cex =", cex,")")) { nex <- length(extras) np <- 26 + nex ipch <- 0:(np-1) k <- floor(sqrt(np)) dd <- c(-1,1)/2 rx <- dd + range(ix <- ipch %/% k) ry <- dd + range(iy <- 3 + (k-1)- ipch %% k) pch <- as.list(ipch) # list with integers & strings if(nex > 0) pch[26+ 1:nex] <- as.list(extras) plot(rx, ry, type="n", axes = FALSE, xlab = "", ylab = "", main = main) abline(v = ix, h = iy, col = "lightgray", lty = "dotted") for(i in 1:np) { pc <- pch[[i]] ## 'col' symbols with a 'bg'-colored interior (where available) : points(ix[i], iy[i], pch = pc, col = col, bg = bg, cex = cex) if(cextext > 0) text(ix[i] - 0.3, iy[i], pc, col = coltext, cex = cextext) } } pchShow() pchShow(c("o","O","0"), cex = 2.5) pchShow(NULL, cex = 4, cextext = 0, main = NULL) ## ------------ test code for various pch specifications ------------- # Try this in various font families (including Hershey) # and locales. Use sign=-1 asserts we want Latin-1. # Standard cases in a MBCS locale will not plot the top half. TestChars <- function(sign=1, font=1, ...) { if(font == 5) { sign <- 1; r <- c(32:126, 160:254) } else if (l10n_info()$MBCS) r <- 32:126 else r <- 32:255 if (sign == -1) r <- c(32:126, 160:255) par(pty="s") plot(c(-1,16), c(-1,16), type="n", xlab="", ylab="", xaxs="i", yaxs="i") grid(17, 17, lty=1) for(i in r) try(points(i%%16, i%/%16, pch=sign*i, font=font,...)) } TestChars() try(TestChars(sign=-1)) # needs MBCS support TestChars(font=5) # Euro might be at 160. Mac OS has apple at 240.