Home / DOE / Charts / Surface Plot / Options

Options¶

This page is the control by control reference for the dialog titled Create Surface Plots. What the finished chart shows is on Surface Plot, and how each plotted value is formed is on Math Details.

One panel, two commands. Surface Plot and Contour Plot are built by the same options panel. The ribbon command decides which chart is drawn, before the panel opens, so there is no control on the panel that switches between them. Three things differ, and all three follow from a contour needing both of its axes quantitative: the dialog title, which factors the two axis pickers offer, and which cells of a grid are drawn. Everything else is the same control doing the same thing, and the matching text appears on Contour Plot Options.

Outputs¶

The left side of the dialog is a box headed Outputs holding a tree with three levels: the worksheet, then each output on it, then each level of that output. Tick the levels you want a chart for. The dialog opens with every level on the active sheet already ticked.

The two upper levels are three-state. Ticking a worksheet or an output ticks everything under it, and clearing it clears everything under it. When only some of the children are ticked, the parent shows a partial state rather than a tick, so the tree tells you at a glance whether a selection is complete.

One worksheet at a time. Ticking anything on a second worksheet silently clears every tick on the one you had selected, and the options on the right rebuild for the new sheet. There is no warning and no way to draw charts from two source sheets in one Create.

If you press Create with nothing ticked, the dialog tells you At least one chart must be selected. and stays open.

This chart is built from a regression sheet only. Design sheets are not offered, because the chart plots a value that only a fitted model can produce.

The level lines therefore always read the fitted names. Under a quantitative output the two levels are the output's name followed by Y-Hat and by S-Hat, never the Y-bar and S-bar a design sheet would give, because a design sheet is never on this tree. The second level is offered only when the output has a usable standard deviation model. Under a binary output the two levels are written probability of followed by the event name and then the non-event name. Under a nominal output there is one line per level, again written probability of followed by the level name, and the last line carries (reference level) after the name.

Ticking the standard deviation level draws the fitted standard deviation as the height of the surface rather than the fitted response. Nothing else on the panel changes with that choice, and the axis ranges, the layout and the set points are applied to every ticked level alike.

In grid mode you get one worksheet per ticked output level, each holding that level's full grid of pairs. Ticking three levels therefore produces three grid sheets, not one sheet with everything on it.

The One specific pair layout writes a worksheet per ticked level in the same way, each holding that level's one chart.

Chart layout¶

The box headed Chart layout decides how many charts one Create produces.

All factor pairs (grid) lays the ticked factors out as a square grid on one worksheet, with the factor names down the diagonal. Every pair appears twice, once with each factor on the horizontal axis, because the two orders are different charts. So four ticked factors give twelve charts on one sheet, not six. Use it to scan a model.

One specific pair draws a single chart from the two factors you name below, and gives it the whole sheet. Use it once you know which pair you care about.

When the selected source has fewer than two factors, no pair can be formed at all. The Chart layout and Factors to plot boxes are disabled, and a message reads: "This source has fewer than two factors, so a surface or contour plot cannot be drawn (it needs two factors to form a pair)."

Factors to plot¶

The box headed Factors to plot carries a checkbox per factor and feeds the grid: the pairs are made from the factors ticked here. It has no effect when you have chosen one specific pair, because the pair is then taken from the two axis pickers instead.

Every entry starts ticked. A design with blocks carries one further entry for the block, which counts as a factor throughout this dialog: it can be plotted and it can be held.

The message this box can raise belongs to the grid alone. Ticking fewer than two and pressing Create reports Select at least two factors for a grid. and creates nothing. In the single-pair layout the ticks are not read at all, so no number of them is too few.

A grid cell is only drawn when its factors suit the chart. On a surface grid the horizontal factor must be quantitative; on a contour grid both factors must be. A cell that fails the rule is left as NA rather than as a chart, so a model with categorical factors gives a grid with gaps in it.

The block is always one of the categorical entries. On a surface grid that means every cell whose horizontal factor is the block is NA, while a cell with the block on the series axis is drawn.

A grid uses each factor's own experimental range and offers no range boxes. The From and to boxes belong to the two axis pickers, which only the single-pair layout shows, so in a grid every quantitative axis runs from the lowest to the highest value that factor took in the data. To plot a different range you have to choose One specific pair.

The two factors of a single plot¶

Choosing One specific pair replaces the factor checkboxes with two dropdowns, Horizontal axis (X) and Series axis (Y). On a Surface Plot both dropdowns list every factor of the design (plus block, when present, spelled lower case as the product spells it); on a Contour Plot both list only the continuous factors, because a contour needs both axes continuous. The two defaults are the first two continuous factors found (or, failing two continuous factors on a Surface Plot, the first two factors of any kind). The two axes must be different factors; pressing Create with the same factor in both reports The two axis factors must be different.

For a Surface Plot, at least one axis must be continuous (At least one axis factor must be continuous. otherwise); for a Contour Plot both must be (A contour plot requires both axes to be continuous. otherwise). On a Surface Plot, if the horizontal axis is set to a categorical factor while the series axis is continuous, the two are swapped before drawing so the continuous factor is always the one that gets a plotted range; the series axis then draws one ribbon per level of the categorical factor instead of a range.

The plotted range of an axis¶

When an axis picker's chosen factor is continuous, a From / to pair of boxes appears below it, defaulting to that factor's actual low and high value, with the factor's experimental range repeated underneath. Both boxes accept only a number (rejecting anything else with Must be a number, checked when focus leaves the box) and carry no built-in minimum, maximum, or requirement that From be less than to. A range that reaches outside the factor's experimental range does not block the chart: pressing Create instead raises a prompt naming the factor, the range typed, and the factor's actual range, and asks whether to create the chart anyway. Answering no returns to the dialog with the values intact. Choosing a different factor on that axis resets its From/to boxes to the new factor's own actual range.

Narrowing a range never raises the prompt. The check compares the From value against the factor's low and the to value against its high, and asks only when one of them reaches outside. A range that sits inside the experimental range zooms in without comment.

Set points¶

A box headed Set points (factors held constant) lists the factors not currently plotted: in grid mode, every factor of the design (each is held constant in the grid cells where it is not one of that cell's own two axes); with one specific pair, every factor except the two chosen axes. Surface and Contour never offer a design sheet as a source, so there is no source-based rule for this box; instead it collapses whenever nothing is left to hold, which in practice means one specific pair chosen on a design with exactly two factors, since both are then the axes and no factor remains.

Each row names one factor. A continuous factor's row is an editable box defaulting to the midpoint of the factor's uncoded valid range, with that range shown beside it (low to high). The box accepts only a number (rejecting anything else with Must be a number, checked when focus leaves the box) and carries no built-in minimum or maximum. A value typed outside the factor's range does not block the chart; pressing Create instead raises the same "create anyway" prompt described above for the axis range, naming this factor, the value typed, and its range.

A categorical factor's row is a fixed dropdown of the factor's level names instead, defaulting to the last level shown.

A box never holds a value that is not a number. This is true of the four range boxes and of every set-point box alike. A box commits what you typed only when focus leaves it, and an entry that does not parse is rejected at that moment rather than committed, so the value the panel holds is always the last one that did parse. Pressing Create while a box is still showing a rejected entry reports One or more entries are not a valid number. Correct the highlighted boxes and try again., moves focus to the first such box, and creates nothing.

Two further messages exist in the code and neither can be reached. The set point for name must be numeric. and The range for name on the horizontal axis must be numeric., which also has a series axis form, guard the same condition a second time when Create builds its selections. The boxes' own rejection means the panel never has a non-numeric value to hand over, so neither message ever fires.

Before it draws¶

If anything you typed reaches outside the range the factor actually took in the data, the software asks before drawing. A set point is one source of that. On the dialogs that carry axis range boxes, which are Surface Plot, Contour Plot and Trellis, a From or to value counts too, as does a trellis slice range, so widening an axis past the experimental range raises the prompt on its own with every set point left alone. The prompt lists each offending entry with the factor's experimental range beside it, warns that the chart will extrapolate beyond the data, and asks whether to create it anyway. Answering no returns you to the dialog with your options intact.

This is a warning, not a refusal. A prediction outside the range of the data is an extrapolation of the fitted model, and the model was never tested there.

While it draws¶

While charts are being written, a status line reports what is happening and a progress bar appears only when more than one chart is being drawn, since a bar for a single chart would sit at 100 percent from the moment it appeared.

Cancel stops the run cleanly between charts, not part way through one. A chart that has already been written stays; the sheet that was mid-write is deleted rather than left half finished. So cancelling never leaves a partial chart behind, but it can leave fewer sheets than you asked for.

Creating with the dialog left open lets you build several charts from one set of options without reopening it. The charts are identical either way: the only difference is whether the window closes afterwards.

When nothing is drawn¶

If the options you chose produce no drawable chart, the dialog reports There are no valid charts selected for the report. and writes nothing. Where the reason is specific, for example an axis rule or a source restriction, that more specific message is shown instead.

On this chart that message means the writing failed, not that the options were empty. Every way of choosing nothing has its own message earlier: no ticked level gives At least one chart must be selected., and in the grid layout fewer than two ticked factors gives Select at least two factors for a grid. By the time the report reaches Excel there is always at least one chart to write, so the message above is reached only when writing every one of them failed.

The dialog is owned by the Excel window, so Excel cannot cover it while it is open. If it seems to have vanished, it is on another monitor rather than behind the workbook.