gvisMerge + gvisAnnotatedTimeLine common RangeSelector

Question

I am using gvisMerge to bring together several gvisAnnotatedTimeLine objects. Is it possible for all the gvisAnnotatedTimeLine objects to all use the same RangeSelector, i.e. if I choose a range between two dates/times in one gvisAnnotatedTimeLine graph, it subsequently automatically adjust the range for the other graphs that were merged together to reflect the same range?

Answer 1

i'm pretty sure the answer is no.

if gvisMerge could change parameter values for the googleVis objects passed to it, then it would need an accessor method and a mutator method (i.e., a getter and a setter), neither of which it has.

What's more, gVisMerge is purely for the placement of exactly two googleVis objects on a single HTML page (in fact formatting more than two googleVis objects at a time requires multiple recursive calls to gvisMerge).

If you look the method signature for gVisMerge:

gvisMerge(x, y, horizontal = FALSE,
            tableOptions = "border=\"0\"", 
            chartid
)

Aside from x and y (the two googleVis objects to merge on a single HTML page), and chartid which is requires just so that the new mreged googleVis object has a unique chartid, the arguments to gvisMerge all relate to formatting or styling:

horizontal = FALSE: whether the two charts are positioned side-by-side or above-below (default)

tableOptions: pure HTML formatting (e.g., for setting a background color for the HTML page or the spacing between the two chart placed on the page via gvisMerge)

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A solution not using gvisMerge:

A chart created from a googleVis constructor is an R object of class gvis and class list.

One component of a gvis object is jsDrawChart, which combines the data and the appropriate google visualization API function with the user options (parameter values to the googleVis function).

So it's the arguments passed to this function that you would want to access and modify, but you have to do this before passing the googleVis object (chart) to gvisMerge--because once you call gvisMerge then you have a new gvis object in which the original annotated timeline chart is one component.

What's more, charts created by googleVis are rendered in Flash; clearly you ought to modify the googleVis objects as early in your workflow as possible. My guess is that shouldn't be difficult because all you need to set common min & max values for the axes is the data set displayed by each chart. Therefore, just calculate a common range ex ante:

> r1 = range(d1)
> r2 = range(d2)

> r1
  [1]  0.23 .75

> r2
  [1]  0.11 0.46

append the returned values from a call to range for each AnnotatedTimeLine chart, then pass in this aggregated range for every call to AnnotatedTimeLine, which will obviously give each chart drawn from the constructor the same min & max values on the given axis.

r12 = append(r1, r2)