Name: CPLOT Purpose: Create contour-, gray scale- and colour plots. Provide basic drawing routines. Category: PLOTTING File: cplot.c Author: M. Vogelaar Keywords: INSET= Set and subset(s) to work on. Maximum number of subsets is 256. The dimension of the input must be 2. BOX= Frame of subset. [whole subset] Decrease area to be plotted. GRDEVICE= Plot device: [List of devices] Destination of plot, Screen or Hardcopy. MOSAIC= Number of ROWS in a mosaic: [No mosaic] Keyword is prompted if number of subsets > 1. This keyword determines the layout of the mosaic. NEXT= Give for next plot. If no mosaic is selected but the number of input subsets is greater than 1, than each subset has its own plot. will start the next plot. ** CALCMNMX= Calculate min. & max. in box (Y/N): [N] If CALCMNMX=N the program displays header values for the minimum and maximum values in the box. If header values cannot be obtained or CALCMNMX=Y, the values are calculated. SCALE= Scale in x & y (units/mm or arcs/mm) [Calculated] Defaults and units are shown in the message and are taken to fit the plot on GRDEVICE=. ===== CONTOUR CONTROL ===== ** PERCENT= Contours (and gray scales) in % (Y/N): [N] If PERCENT=Y the contours (and grayscales) are percen- tages instead of discrete values. CONTOUR= Give contours (min=..., max=... ): [None] The contours are given in units of your image, or percentages. Maximum number of contours is 128. ** COLIND= Color indices for contours: [Calculated] If you give more than 0 indices but less than the number of contours, the remaining indices are copied from the last one specified. ** CSTYLE= All cont.(S)olid, dash (O)dd or (N)egative [N] Distinguish contours by dashing the odd or negative contours. ** CWIDTH= Linewidth for contours [1..21]: [same as LINEWIDTH=] ===== GRAY SCALES ===== GRAYSC= Gray scales: [No gray scale map] Draw a gray-scale map of the image values. The gray scales are given in units of your image or percentages. For each interval a shade is calculated. Minimum number of scales is 1, maximum is 128. ===== CREATING A COLOUR PLOT ===== COLPLOT= Do you want a colour plot? Y/[N] A colour plot is made in interaction with GIDS. The GIDS colour Look Up Table and levels are used by the program to create a colour plot. GIDS must be available and set to your own preferences. Your graphics device must be a colour device (e.g. GRDEVICE=LCPSFILE). See description. ===== CONTROL PHYSICAL COORDINATES ===== ** TICK= separation between major ticks in x,y [calculated] Units are physical units of the axes, except when the units are 'DEGREE' then the input is in seconds of arc. If an axis is labeled 'RA' and is unrotated, then the units are in seconds of time. ** NMINOR= Number of minor ticks between major ticks [Calculated] ** EXTEND= Extend major tick lines in map? Y/[N] ** LINESTEPS= Number of steps in tick lines: [40] More steps takes more time but result in smoother lines. Keyword in only asked if EXTEND=Y ===== LAYOUT OF PLOT ===== ** MEAGRE= Plot without units and labels: [N]Y If a plot is wanted without something along the axes, use MEAGRE=Y ** GRIDMARGIN= Gridmargins in mm in x, y: [0 0] Grid margin in x, y-direction. If one value is given, the second is copied from the first one. ** TITLEMARGIN=Title margins in mm in x, y: [Calculated] Title margin in x, y direction. The defaults are 10 mm if XTITLE= and YTITLE= are specified. Otherwise they are 0 mm. If one value is given, the second is copied from the first one. ** LABELMARGIN=Label margins in mm in x, y: [Calculated] Label margins for the physical coordinates along x- and y axis. ** INFOMARGIN= Info margin in mm (x-dir): [Default by program] Default width for info is 50 mm. ** LINEWIDTH= Line width in plot [1..21]: [1] ** XTITLE= Title along the X axis: [Axis name from header] ** XTPOS= X-title position x,y (mm): [Calculated] ** YTITLE= Title along the Y axis: [Axis name from header] ** YTPOS= Y-title position x,y (mm): [Calculated] ** AXMASK= Mask for ticks & units for axes: [Y Y Y Y Y N N Y y] Enable(Y)/Disable(N) plotting tick marks (4 axes) and physical coordinates (4 axes) along lower, right, upper and left axis. Default is draw tick marks along all axes and the physical units along the lower and left axis only. Axes are counted anti clockwise, starting with the lower x-axis. The last value indicates plotting of ticks along axes shared by two plots in a mosaic. COMPOS= Give position for text: Positions can be given either in grid or physical coordinates. Default is the previous position. COMMENT= Comment in plot: [Stop comments] Before plotting text there are some attributes to set (defaults are given by the program). Specification is requested for the axis text and comments. After the first comment, the keywords are hidden. ===== TEXT ATTRIBUTES ===== ** LABELATT= Hght,Wdth,Fnt,Jstf,Era,Angl,Col [calculated] ** COMMATT*= Hght,Wdth,Fnt,Jstf,Era,Angl,Col [calculated] * is a wildcard for a comment number: COMMATT1= : attributes for first comment in a (sub)plot COMMATT2= : " " " second ...... If COMMATT= (without comment number), the effect of all COMMATT*= keywords is overruled. This keyword is canceled, so it can be used in a recall file. ** SUBATT= Hght,Wdth,Fnt,Jstf,Era,Angl,Col [calculated] ** GRIDSATT= Hght,Wdth,Fnt,Jstf,Era,Angl,Col [calculated] ** TITLEATT= Hght,Wdth,Fnt,Jstf,Era,Angl,Col [calculated] ** INFOATT= Hght,Wdth,Fnt,Jstf,Era,Angl,Col [calculated] ===== INCLUDING A PHYSICAL SUBSET COORDINATE IN A MOSAIC ==== ** PLSUB= Plot phys. coord. of subset in plot? [N] Keyword can be set if dimension of the set is greater than 2. (See also SUBNUM= keyword) ** SUBNUM= Plotnumber(s) to exclude plotting phys.coord's: [none] Exclude plotting the physical coordinate label in panels given by SUBNUM= The upper left panel is panel 1. ** DECIMALS= Decimals in phys. coord. of subset: [2] ** SUBPOS= Position of physical sub. coord.: [Calculated] Enter ONE alternative position for the labels that mark a subset. ===== PLOT INFORMATION ===== ** PLOTINFO= Information in plot? Y/N: [Depends on device] If the device is a hardcopy device the default is Y(es) otherwise it is N(o). The text contains info about contours, grayscales etc. and is located at the upper right of the plot. ** INFOCOM= Comment in plot info: [No comment] Plot info can contain user supplied comment. Keyword is asked in a loop. The loop is aborted with carriage return. The keyword is hidden only the first time it requests input. ===== ADDITIONAL FEATURES ===== GRID= Frame with grid labeling Y/N: [Y] In a mosaic only isolated axes have grid labeling. MARKPOS= Give marker position(s): [Stop input] marker. There is a loop over this keyword (so a recall file can be used here). Exit loop with carriage return. Maximum number of positions is 512. MARKER= Graphics markers: [All 2] You can give as much different markers as there are specified (valid) positions after the use of MARKPOS= ** BEAMPOS= Central position of ellipse corresponding to the beam you want to plot. If you specify a position, the beam characteristics from the header will be used as defaults for the next keywords. If the map is not a spatial map the beam is replaced by error bars. ** BEAM= Beam major and minor axis FWHM in arcsec: [Header values] If values cannot be found in the header, the physical value of the grid spacings are taken as defaults. ** BEAMPA= Position angle of beam in degrees: [Header value] ** BEAMATT= Erase, Separation (mm), Slope (deg), shape: [0,1,45,1] argument 1) 0 Do not erase box around beam 1 Erase box around beam. argument 2) Shade lines have a default separation of 1 mm argument 3) Default slope of the shade lines is 45 deg. wrt. major axis. argument 4) 1 Plot elliptical beam. 2 Plot rectangular beam (IRAS survey, long slit spectroscopy) ** BEAMNUM= Plot number(s) to plot a beam: [last plot] ===== DRAWING STRAIGHT LINES IN PLOT ===== ** PLLINE= Draw line to/from x1,y1 (to x2,y2): [No line] If two pairs are given, than a line from x1,y1 to x2,y2 is plotted. If only one pair is given, a line is plotted from the previous end point to this point. As soon as one line is defined, the PLLINE keyword is prompted in a loop and is not hidden anymore. The loop is aborted with carriage return. ** PLATT= Width, Style, Color: [Calculated] Attributes for lines: Width: 1..21 Style: 1..5 Color: 0..15 ===== DRAWING ELLIPSE(S) ===== ** ELLPOS= Central pos. for ellipse: [abort loop] ** ELLATT= Width, Style, Color: [Calculated] Attributes for ellipse: Width: 1..21 Style: 1..5 Color: 0..15 ** ELLAXESPA= Beam maj, min (arcs) & PA (deg): [0 0 0] For maps where one or both axes is not spatial, the major and minor axes are in pixels. The rotation angle is in degrees. 0 deg. means that the major axis is aligned with the declination axis, there is no correction for the angle in rotated maps. ===== OVERLAY OVER EXISTING IMAGE IN GIDS===== ** OVERLAY= Overlay over existing image in GIDS? Y[N] Only possible if a set is already displayed in GIDS. Default for the overlay set is the set name and subset of the image already displayed in GIDS. ===== OVERLAY OF NEW (SUB)SET(S) ===== ** INSET2= See above BOX2= " CONTOUR2= " COLIND2= " ** CSTYLE2= " GRAYSC2= " COLPLOT2= Do you want a colour plot? Y/[N] ===== CURSOR INTERACTION ===== ( Only working properly in GIDS ) ** INTERACTIVE=Purpose is to call an interactive cursor routine to be able to mark positions in the plot or to get and convert positions and put the values in the log-file. P : Plot marker at this position Q : Quit interactive cursor mode Description: Among standard ways of presenting astronomical data are contour and grayscale plots. If a map is represented by f(x,y), contours are lines of constant f. This requires the data you want to present with this program must be 2 dimensional. Therefore sets with more than 2 axes need a subset specification at INSET=. Information about the syntax can be found in the GIPSY users manual. The names of the axes can be found with the programs HEADER or DISK. If only a part of the data need to be displayed, use BOX= with four arguments to decrease the size. Input can be a lower and an upper coordinate pair, a coordinate pair and combination with physical coordinates. See the GIPSY user manual for the use of physical coordinates. If you want to display more than one subset of a set (INSET=AURORA F 1:10) you get each subset on a blank screen or paper (advancing to a new page or clearing the screen is controlled by the NEXT= keyword) unless you want to display all the data in a mosaic. With MOSAIC= you can give the number of rows in the mosaic. The program calculates the number of columns. The first plot will be in the upper left corner of the screen or paper. Each subset in a mosaic will now be called 'subplot'. Contours The contours at CONTOUR= are a series of floating point numbers given in units of your map. This keyword obeys the syntax for reals as described in the GIPSY user manual. This includes the use of expressions also. An example could be CONTOUR=LOG([10:1000:50]) which is evaluated to 1, 1.77815, 2.04139, 2.20412, ...., 2.98227 Contours will be plotted with the same line width as the axes of your plot. The blanks in your data are ignored, making gaps in the contour map. The contour levels can be given in percentages also. To put input in percentage mode, select PERCENT=Y. The conversion from percentages to absolute levels is done with the formula: level[i] = min + perc[i]/100 * [max-min] so that 0% results in the level 'min' and 100% results in the level 'max'. The values min, max are the minimum and maximum values of the data as recorded in the header of the current (sub)set. If you don't trust these values or if your box is smaller than the entire (sub)set, use CALCMNMX=Y to calculate these values. The min and max are also calculated if PERCENT=Y and no header items DATAMIN and DATAMAX are found in the header. If plotting more than one contour, you can select a contour style to distinguish negative from positive contours, (default CSTYLE=N), or odd from even contours (CSTYLE=O). If you want all contours to be solid, use CSTYLE=S. Contours are associated with a color index. This index is an integer number that corresponds to a device dependent color. For a color plot you can use in COLIND= the color indices: 0 Background 1 Default (Black if background is white) 2 Red 3 Green 4 Blue 5 Cyan 6 Magenta 7 Yellow 8 Orange 9 Green + Yellow 10 Green + Cyan 11 Blue + Cyan 12 Blue + Magenta 13 Red + Magenta 14 Dark Gray 15 Light Gray 16-255 Undefined The number of color indices must be equal to the number of contours. If COLIND= the indices are calculated by the program. If at least one value is given but the number of indices is less than the number of contours, the remaining indices are copied from the last one specified. For a black and white hardcopy you can use 0 for a white contour and 1 for a black contour. This combination is sometimes used to emphasize the contours in dark regions of a gray scale plot. If the device is the screen, the color indices will not be very useful. The width of the contours is controlled by CWIDTH=. Together with LINEWIDTH= and PLATT=, these keywords control the width of the lines to be plotted. The smallest number is 1 the largest possible number is 21. The CWIDTH= keyword is asked hidden just before plotting a contour, making it possible to draw different contours in different widths. The default values of all the keywords containing widths is 1 if the plotting device is the screen or 2 if it is a hardcopy device. Example: CWIDTH=4;3;2;1 The lowest contour has width 4, the highest has width 1. The semi colons are important here because CWIDTH= accepts only one number at a time. ** Trick: If the minimum value 1 is too thick on paper, there is a possibility to set 'setlinewidth' in your postscript file to a smaller value Devices The destination of the plot is selected with GRDEVICE= If you give only, you get a list of devices that can contain for example: X : Tektronix window on screen L1LASER : QMS laser printer 1 in landscape mode P1LASER : QMS laser printer 1 in portrait mode LCOLOUR : Colour printer in landscape mode PCOLOUR : Colour printer in portrait mode NULL : null device (no plot output) etc... On some printers it is possible to plot on a transparency instead of paper. Instructions are obtained at local system management. Gray scales Instead or along with drawing contours, it is also possible to fill your plot with shades representing the image values. The shades are given in GRAYSC=. The maximum number of shades is 128. Again, input values are floating point numbers and expressions are allowed. The scales are in units of the map and must be in ascending order. Example: GRAYSC=2 3.5 8 Image values smaller than 2 are white in the plot. Values equal to or greater than 2, but smaller than 3.5 get the first shade of gray, values 3.5 <= f(x,y) < 8 get the second shade of gray and values >= 8 are black in the plot. The available number of different shades depend on the selected device. If PERCENT=Y, the gray scale values are percentages. ** Hint If you want to fill contours smoothly with gray scales, (contours can intersect the 'gray scale pixels') simulate more pixels by regridding the map. Use REPROJ with changed grid spacings to achieve this effect. Color plots Color plots can be made if you specified color indices for text or contours and send the plot to a color printer. As soon as the program knows that you want to use a color printer, you are also able to print colored pixels instead of gray pixels. The image data is translated to colors according to .......... Layout A plot consists of a title along the lower x-axis and left y-axis, a space for labels containing positions in physical coordinates, a grid margin to reserve space for plotting positions in pixels, the plot itself and an area where important information about the plot is displayed. Titles The default titles along x and y axes are the names of these axes as found in the header. Titles can be altered with XTITLE= or YTITLE= The keywords accept text strings. A string can contain escape sequences. These are character- sequences that are not plotted, but are interpreted as instructions. All escape sequences start with a backslash character (\). \u Start a superscript or end a subscript; \d Start a subscript or end a superscript; (\u and \d must always be used in pairs) \b Backspace, i.e. do not advance text pointer after plotting the previous character; \\ Backslash character; \A Angstrom symbol; \gx Greek letter corresponding to roman letter x; (Lower case and upper case x give different greek characters ) \fn Switch to Normal font \fr Switch to Roman font \fi Switch to Italic font \fs Switch to Script font Like all 'plot' text, the text can contain so called PGPLOT symbols. Available symbols (~1000) are arranged according to Hersey's numerical sequence and are listed in Table B.1 of the PGPLOT manual. Any character can be inserted in a text string using an escape sequence of the form \(n), where n is the 4-digit Hersey number. The positions of the titles are calculated by the program but can be altered with XTPOS= and YTPOS=. Each keyword accepts a coordinate pair in mm. The numbers are absolute positions in the plot. If for some reason there is not enough space along the axes to place the title, increase the default values (10 mm in x and y direction) at TITLEMARGIN= If only one number is given, the y value is automatically copied from this value. Position in pixels Positions along the axes can be in pixels and physical values. If GRID=Y, each 10th pixel position will be marked inside the plot box. Default there is no room reserved in x and y direction so the numbers can spoil the layout of the plot if contours reach the borders. But extra space for the grids can be reserved. This space is controlled by the keyword GRIDMARGIN= which accepts two numbers for space in x and y direction. If only one number is given, the y value is copied from this value. If GRID=N (default) there are no grid margins. Physical values The labels along the axes indicate the physical positions i.e. if transformation from pixels to physical coordinates is possible. If transformation is not possible, the possible reason is mentioned in your log-file. There the program puts the result of transformation of pixel 0 to a physical position. Conversion always take place to the primary axis units as found in the header (CUNIT#). If there are also secondary units, the program will convert the pixels to these units. The default separations between two positions is calculated by the program. A position label is plotted together with a marker called a Tick. Space between two are controlled by TICK=. It accepts values for the x and y direction overruling the calculated default values. Negative numbers will be converted to positive numbers. The units are the axis units except if the header unit was 'DEGREE'. The values are in seconds of arc then. If an axis is the RA axis of an unrotated map, the TICK= units are in time seconds. Between two major tick marks there are minor tick marks. The default number is calculated by the program. The numbers of minor ticks in x and y direction can be changed with NMINOR= If you don't want minor tick marks, use NMINOR=0 0 It is possible to plot labels for all axes, but in most plots only the lower x axis and the left y axis do have labels, while the others have ticks only. For a single plot this is the default labeling. In a mosaic, lines connecting two 'subplots' have tick marks only. The decision to plot ticks or labels is made after AXMASK= The keywords accepts 8+1 entries. An entry is Y or N. The first four values indicate the plotting of ticks and the second four indicate the plotting of labels. Default is AXMASK=Y Y Y Y Y N N Y y Counting of the axes is anti-clockwise and starts with the lower x-axis. The last value indicates plotting of ticks along axes shared by two plots in a mosaic. The default is Y. If you change this to N, there will be no ticks on the 'inside' axes of a mosaic. Space for the labels along both axes is calculated, but it is not known to the program beforehand how large the labels along the y axis are going to be. Therefore sometimes the space between these labels and the y title is to big. The spacing is controlled with LABELMARGIN= which accepts two values. The first is the space in mm in the x direction (for the y-labels) and the second is the space in the y direction. Rotated images Along spatial rotated axes, only offsets are plotted. An offset is wrt. a point in your map which is pixel 0 if this pixel is inside the box or the central pixel if pixel 0 is not in the box. Scales The plot is scaled in some way to fit on paper or screen. First the physical size in mm of the device plot area is determined. From this number the margins for grids, labels titles and info is subtracted. This number is divided by the number of subplots in one of the directions and is scaled onto the number of pixels in that direction . After a correction for the grid margin we end up with a scale in grids/mm. Changing these values can be done with SCALE= but then the scales are converted to units/mm. These units are the physical units as found in the header, only if the units are 'DEGREE', the scale input must be in ARCSEC/mm then. If both axes have the same units, then the scales are made equal in both directions. Plot information Information about plot characteristics is placed in the log file and some is also placed in the plot. The keyword that can be used here is PLOTINFO= which is N for the screen and Y for other devices. Note that this parameter also influences the scaling in your plot. Info in the plot contains items like the object name, the set name, used box, units, scales etc. It can be extended with a user supplied comment in INFOCOM= which is asked in a loop that is aborted with carriage return. The info is closed with a time stamp which is also placed in the log file so that you're always able to find the corresponding information in the log-file (GIPSY.LOG). FEATURES Marking of positions Positions in a plot can be marked. The positions are taken from MARKPOS= The keyword is asked in a loop and canceled after each specification. In this way it made suitable for using so called recall files. Example: MARKPOS=. Each comment can be in different height, width font etc. These so called text attributes are connected with the text attributes keywords. The text string can also contain escape sequences. These are character-sequences that are not plotted, but are interpreted as instructions. Text attributes keywords Input are 7 floating point numbers that control the appearance of the text to be plotted. The input syntax is: XXXXXATT=Hght,Wdth,Fnt,Jstf,Era,Angl,Col [x1,..,x7] More specific: Hght: Character height It's a normalized value corresponding to about 1/40 of the height of the plot device. Wdth: Thickness of chars & lines (1..21): Fnt: Font type 1,2,3, 4: 1 single stroke "normal" font 2 roman font 3 italic font 4 script font Jstf: Justification of text: 0=left, 0.5=middle, 1=right of a given coordinate. Era: Erase text box first before plotting text. 0 = Do not erase background. 1 = Erase background for the number of characters found in the text. n = Erase background for the n characters. Angl: Angle of text, 0 is horizontal. Col: Character color, for indices see color indices above. Not all text obey these attributes. For example labeling has its own justification and has no erase option. Defaults are all determined by the program. Defaults: LABELATT=1.0, currentlinewidth, 2, 1, 0, 0.0, currentcolor COMMATT*=1.0, currentlinewidth, 2, 1, 0, 0.0, currentcolor TITLEATT=1.0, currentlinewidth, 2, 1, 0, 0.0, currentcolor INFOATT= 0.5, 1, 2, 1, 0, 0.0, currentcolor SUBATT= 0.6, currentlinewidth, 2, 1, 0, 0.0, currentcolor GRIDSATT=0.5, currentlinewidth, 2, 1, 0, 0.0, currentcolor * is a number from 1 to the number of comments in one (sub)plot If the number is omitted, each COMMATT= keyword overrules the current COMMATT*= specification. COMMATT= is canceled and therefore can be used in a recall file. This option is used if the number of keywords is greater than allowed for a default file. Then the attributes can be stored in a recall file. Extended ticks The tick marks can be extended so that they are connected by curves following the current projection (EXTEND=Y). The number of points calculated in a curve is determined with LINESTEPS= Default is 40 points, for a quick look you can do with less points, but for a quality plot 40 will probably not be sufficient. The extensions of ticks in other sky systems is not yet implemented. Drawing lines in plot To add some free style plotting use PLLINE= The keyword is hidden but after specification it will be asked unhidden in a loop that is aborted by PLLINE= The keyword accepts at most 4 floating point numbers i.e. 2 coordinate pairs (in pixels or physical coordinates). The action that follows is the plotting of a line between the two points. If the keyword appears again and you specify only one coordinate the line is plotted from the previous last coordinate to the specified coordinate. An application for these lines is the indication of zero levels for instance. The line width, style and color are controlled by PLATT= The range in width is [1..21], the range in colors is [0..15] and line style is one from: 1 Full line 2 Long dashes 3 Dash-dot-dash-dot 4 Dotted 5 Dash-dot-dot-dot Plotting ellipses ELLPOS= is a position in grids or physical coordinates. If the keyword is not empty, you start a loop in which a beam and angle is asked in ELLAXESPA= First value of this keyword is the major axis, second the minor axis and the third is the angle in degrees wrt the positive y axis. The units of the major and minor axes are in seconds of arc if both axes in the plot are spatial axes, else, the units are grids. The appearance is controlled by ELLATT= (see remarks at PLATT=). Overlays CPLOT distinguishes two overlays. The first is an overlay over an existing image displayed in GIDS (for example displayed with the program VIEW). The hidden keyword OVERLAY= must be set to YES. CPLOT then, calculates the defaults needed to fit the overlay. The default for INSET= will be name and subset of the set that is already displayed in GIDS. The default for BOX= will be calculated. The program tries to create a box that is equal (in physical coordinates) to the box of the currently displayed set in GIDS. If the overlay box is smaller, everything outside that box will be erased before the labels are written. A default scale is calculated so that the overlay will fit. The rule for a new scale is: OldGridSpacing NewScale = OldScale * -------------- NewGridSpacing There is not a prompt for GRDEVICE= (because the specifi- cation MUST be GRDEVICE=gids//append). The gridmargins are both set to zero. The second type is an overlay of contours over the existing ones. These overlays are made possible by asking in the current plot for a new (sub)set with INSET2= The keyword is hidden so it must be specified beforehand. If no more overlays are needed use INSET2= to abort the overlay loop. For each subset it is possible to create overlays. The program calculates a box for the new (sub)set so that it is contained in the original box in physical coordinates. With the prompted keyword BOX2= you can rearrange these values. Pixel 0,0 in the original set is transformed to physical coordinates which are converted to a pixel position in the new set. From this point on all new pixels are scaled with new scales. A new scale is calculated as described above. There is no check on projection. You have to decide yourself whether the overlay makes sense or you have to use the program REPROJ first. The keywords CONTOUR2=, COLIND2=, and GRAYSC2= are described under CONTOUR= etc. If you select no original contours and gray scales in a mosaic, but use INSET2= for a second (sub)set, it is possible to use different data origins in your mosaic or use different contours per subset etc. Colour plots To create a colour plot, it is not necessary anymore to use OVERLAY=Y and make a hardcopy of the result in GIDS. Now you can select a colour option with the keyword COLPLOT=Y. For the graphics device you have to select a colour device ( e.g.: GRDEVICE= LCPSFILE (or PCPSFILE, LCOLOUR, PCOLOUR) ). Now the program wants to know how to translate the data values of your (sub)set to colours. You have to use GIDS for this. In GIDS you can view your (sub)set and set levels and colours to your own preferences. If you are satisfied with what you see, run CPLOT COLPLOT=Y and the colour plot can be made. It is convenient to send the plot first to a PostScript file (GRDEVICE=PCPSFILE or LCPSFILE) and view the result with a viewer like 'gs' (Ghostscript) (Tip: do not leave GIDS while viewing with 'gs'). Together with the INSET2= keyword, the keyword COLPLOT2= can be used to make colour plots with different colour characteristics. See also the remarks about plotting grayscales. If you want to use your own colour look up table, use the program COLOUR. It loads a COLOUR Look Up Table in GIDS. The LUT can be activated in GIDS with the USER button in the COLOR menu. Notes: WARNING: If you want to use a grayscale map in your overlays, make sure that this is your first (sub)set. Otherwise a grayscale map will obscure all previous plotted contours in a hardcopy. Examples: Examples of default files: 1) Create contour plot of subset containing 'short observation beam' (data from A. Broeils). Note the special use of the comment keyword. linewidth=2 BEAMPOS= BOX=-80 -80 80 80 CONTOUR= -0.1 -0.05 -0.025 0.025 0.05 0.1 0.2 0.4 0.8 GRAYSC= GRDEVICE=x GRID= n INSET= app 1 SCALE=10 10 tick=360 360 nminor=1 1 markpos= compos=10 51.8;-31 45;-10 29;-43 49;-70 65; comment=\(2522);\(2522);fan beam;res. axis;(b) commatt1=1 2 2 0.5 0 126; commatt2=1 2 2 0.5 0 -144; commatt3=1.2 2 2 0 0 36; commatt4=1.2 2 2 0 0 -54; commatt5=1.2 2 2 0 1; xtitle=R.A. - offset (arcmin) ytitle=Dec. - offset (arcmin) titleatt=1.5 2 plline=-20 30 10 51.8; -31 45 -20 30; platt=3;3 labelatt=1.3 2 plotinfo=n The use of a Hersey symbol is demonstrated in: comment=\(2522); .... 2) Example of mosaic and use of recall files. There are five rows in the mosaic. INSET=clean 1:29:2 BOX=-50 -65 60 35 GRDEVICE=x PLOTINFO= MOSAIC=5 LINEWIDTH=1 PLSUB=y SUBATT=0.8 1 2 0 1 DECIMALS=0 SUBPOS= PERCENT=n CONTOUR=-0.48 -0.24 0.24 0.48 0.96 1.44 CSTYLE= GRAYSC= GRIDMARGIN= labelmargin=25 9.1 SCALE=15 15 GRID= MARKPOS=