Encyclopaedia Index


---- Autoplot Help ----

PL[OT] [i] [j]
Plot data elements i - j using a solid line to join the data points. If i & j are unspecified, all data elements in memory but not on the screen will be plotted.

See also HELP on : BLOB, BLB, DOT


------ Command; group 23 --------------

PLOT....command used for plotting field values as CONTURs or PROFILes, according to the PATCH-type set and over the PATCH prescribed. It has four arguments.

(a) CONTUR plots

Contour plots for one or more variables may be elicited over any portion of a plane of constant IX, IY or IZ indicated by the arguments of PATCH, when it has CONTUR as its second argument. In this case, the significance of the 3rd and 4th arguments of PLOT are as follows. The third argument of the corresponding PLOT command is significant only when the CARTES is F ( ie the polar-coordinate grid is employed) and the contours are being plotted for a plane of constant z; then a zero gives a rectangular plot (angle is horizontal, radius vertical ); whereas insertion of 1.0 will produce a polar plot. The fourth argument indicates how many contour intervals are required.

For example, the following commands give contour plots for H1 ( in 20 intervals ) and for C1 ( in 10 intervals ) in one quadrant of the plane at IX=3:

PATCH(name,CONTUR,3,3,NY/2,NY,NZ/2,NZ,1,1) PLOT(name,H1,0.0,20.0) PLOT(name,C1,0.0,10.0)

See CONTUR, NCOLCO and NROWCO for related information.

(b) PROFILe plots

Profile plots for one or more variables may be elicited over any row ( or portion of row ) of cells at constant IX, IY, constant IX, IZ, constant IY,IZ and constant IX,IY,IZ in transient calculations. The row of cells is indicated by the last 8 arguments of PATCH when it has PROFIL as its second argument.

The profiles corresponding to the dependent variables mentioned in the PLOT statements may be plotted either singly or together. In the former case, the values are plotted horizontally, and in the latter they are plotted vertically. IPROF=0 gives the former arrangement, and IPROF=1, 2 or 3 gives the latter. See IPROF, for further information, including the various meanings of the PLOT arguments.

For the default of IPROF=1, the following commands plot the variation with time of P1 and W1 at the cell NX/2, NY/2, NZ/2, on the same plot:


In a parabolic calculation, the following setting,
plots the profile of the axial velocity as a function of IZ.

See also PROFIL and IPROF for related information, and ABSIZ and ORSIZ for control of the box size printed.

Many examples of the use of PROFIL and CONTUR line-printer plots are to be found in the PHOENICS Input Library.

Plot rotation in PHOTON

The ROTATE command causes the rotation of the plot about an arbitrary axis in 3D. The format of the command is:

RO[tate] AX[is] <axis specification> ANG[le] <angle>....

The axis may be specified in the same way as for VIEW and UP commands; angles are in degrees, and may be positive or negative. In order to rotate about the VIEW direction, enter ROT <angle>. For example, ROT AX 1 1 1 ANG 30 will cause a rotation of 30 degrees about the 1 1 1 axis.

NOTE that rotations are cumulative. This command causes an immediate redraw.

Plot sizes in AUTOPLOT

Four sizes of plot are available, and are known by the names "big", "little", "full" and "page". The default size is "full". To change t plot size it is necessary simply to enter BIG, LITTLE, FULL or PAGE according to which is the new size required.

The "little" size is arranged so that a Tektronix 4014 hard copy wil fit neatly into a standard CHAM half-page report box. Hard copy from other devices may vary in size, but the relative proportions will be preserved.

The "big" size has the same proportions as "little", but occupies th full width of the screen, and the text is composed of larger charact A hard copy will fit in a half-page report box after a 70% reduction on a copying machine. Reduced "big" plots are preferable to "little" plots because the lines and characters are made clearer in the reduc process.

The "page" size is arranged so that a hard copy will fit into a CHAM whole-page report box. It occupies the whole height of the screen, a has small-size characters.

The "full" size occupies most of the screen area, and employs large- characters. When reduced, it will fit in a CHAM page-size box, but w more wasted space than the "page" size.

Plot, creation of in AUTOPLOT

When several data elements have been created, you can plot them by using the PLOT command. Each data element is drawn as a set of continuous straight lines joining the data points.

If there are as yet no plots present on the screen, the PLOT command will produce a plot showing all the existing data elements. The plot will be scaled to accommodate all the data elements, and the axes will be calibrated automatically.

If there is already a plot on the screen, the PLOT command will cause any data elements as yet unplotted to be plotted; the scales will, however, remain unchanged.

Thus the two sequences of commands:

  1. DATA, DATA, PLOT; and

will each create two data elements and plot them. In the first case, the plot will be scaled to fit both data elements, but in the second case the scaling will fit the first element only, so that parts of the second element may lie outside the window defined by the axes, and hence not be visible.



PLOTS....See entries for CONTour, OUTPUT and PROFIL, and SUBROU for a description of GRAPH.

Plots, framing of in AUTOPLOT

AUTOPLOT plots are surrounded by a frame, unless the contrary is desired, in which case the frame may be removed by the BOX command. This command alternately removes and restores the frame on successive applications. The frame is particularly useful when adding text or keys since these cannot be placed outside it.

The standard frame is a simple box surrounding the plot. Sometimes it is desired to create panels for use as transparencies, or figures for reports. The commands SLIDE and PANEL change the format of the frame to have three additional boxes for figure headings and titles. SLIDE puts the extra boxes above the plot, and PANEL puts them below. The normal format is regained by entering the command again. Both formats are standard CHAM slide- panel and report-box sizes.

Plots, line-printer, format of

(see IPROF)

Plots, scaling of in AUTOPLOT

If parts of the plot lie outside the axis window, as in the second example above, you may rescale the plot by using the SCALE command. This clears the screen and redraws the plot so that all existing data elements will fit within the window. Thus the second command sequence above, followed by a SCALE command, will achieve precisely the same result as the first.

The SCALE command adjusts the scaling automatically. Users may, however, wish to have precise control of the scaling to be adopted. You use the SCALE X and SCALE Y commands to do this; these enable you to specify the ranges of values to be covered on the x- and y- axes respectively. It is important to note that "x" and "y" here refer to the horizontal and vertical axes on the screen, and not to the PHOENICS coordinate directions. If the plot is to be scaled to fit an individual element or range of adjacent elements, the command SCALE ELEMENT should be used.

Calibration of the axes is performed automatically.

Plots, setting of

(see PATCH)

Plots, sweeps for

(see IPLTF and IPLTL)

Plotting Order

------------------------- Plo Photon Help ----

[Plotting Order] activates a sub-menu to enable you to change the order in which PHOTON plots the various types of graphical elements (grids, vectors etc) when redrawing. The default order is 1=grids, 2=contours, 3=vectors, 4=geometry, 5=surfaces, 6=text, 7=streamlines.