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With this functionnality, StatEL fills one of the oldest gaps of Excel's graphic tool : the opportunity to diplay points of a data set on 3 dimensions with ability of rotation, zoom on a specific area of the graph, display of points labels...
1 - Launch of 3D plot construction :
StatEL needs you to specify the range of cells corresponding to the 3 required measures series. Each triplet of values (x, y, z) represents coordinate of one point. Data must be organized in columns with name of variables in upper cell. If your columns are not contiguous, you have to proceed to a multiple selection through 'Ctrl' key.In case of mistake, you just have to resume your selection.
Then you have to select range of cells contening of observations (StatEL specifies the number of cells that is required, according to your previous selection) :
2 - Display of 3D Plot :
Graph, as well as modification tools, appear on a new sheet of your Excel workbook.
By default, points are observed as projection on plane constitued by 2 first variables of your data set. Each of the 3 planes has its own color (red, blue and green). You can move position of observer (i.e. you) by changing angles of observation via horizontal scrollbars :
Cells on the left of the 3 first scrollbars show values (in degrees) of your rotation since start position, according to 3 axes.
Lowest scrollbar informs you on distance to scatterplot. This functionnality is useful when the 3 variables are measured with very different scales. In this case, planes of projection may look weird. This is due to anamorphosis distortion (cf. below) you can correct by "moving far" from the graph (i.e. by increasing value of lowest scrollbar).
In order to ease perception of relative positions of points, you can visualize projections of points on the 3 planes via option buttons :
At last, checkboxes just above the graph allow you to :
- display names of every points on the graph,
- center planes of projections on point (0, 0, 0),
- remove automatic scale, because if you change value of scrollbar which determines your position relative to the scatterplot, you will not have the "sensation" to go away if automatic scale is activated : untick this case and change value of the lowest scrollbar and you will see scatterplot increase or decrease. This function is useful if you whish to zoom in on a particular area of scatterplot :
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