Open Rubbersheet.net. Finally, a different data set!

This data is elevation data for the land surface and ocean bottom of the southeast United States and Caribbean basin. We'll return to this data set in our program building exercises. This is a good data set to use the Rotate View Control on. Do you remember how to invoke it?

Image window Options: View Control…, mode Rotate, drag on object. Or Ctrl-R while the mouse is over the Image window.

Drag from bottom to top to tip the surface back as if you were flying in from South America.

The term rubbersheet is probably self-evident after you've tipped the data up and revealed its "3D" nature. To be technical, this is still 2D data: it's an infinitely thin surface, but that 2D surface is projected up into the third (height) dimension. As a result, some computer graphics people refer to this as "2.5D".

Think about the form that the data must have to make this object. We start with a 2D array or grid of positions in space (longitude or X, and latitude or Y). At each grid point [X, Y], we have a data value of elevation. When we pass this object into Rubbersheet, it knows to take the "data" value and use it to project the [X, Y] grid into the third or Z dimension at each point, proportional to the elevation value at that point. The actual distance is scalable (Rubbersheet picks a "good" value, but you can change it within the program), so it is not necessarily plotting elevation using the same units as the longitude and latitude values.

Optional: View this Technical Aside if you want more detail on this subject; the information is not required to understand the upcoming material.

We picked this kind of data for the first example of Rubbersheet because most people intuitively understand "height" above a surface. But consider a data set mapped onto a 2D array in which the data values are voltages or electron densities or milk prices, for example. While these don't inherently imply "height", Rubbersheet can be applied to these data as well to make a display of a stretched grid with the highest peaks proportional to the greatest voltage or density or price. Thus, this is a general-purpose visualization tool, not at all limited to showing data that is inherently "height" related, like elevations.

Mental exercise: a traditional 2D line plot is a rubbersheet of 1D data! Consider which values make up the independent variable and which are dependent. Answer

We could have come up with a way to use RubberSheet on the water molecule data using only the modules we've discussed do far: see if you can think of a way. Answer

(hard): OK, if we Rubbersheet the MapToPlane data for water molecule, in which direction does the Rubbersheet project? Answer

As we go along, think about how to re-purpose some of the visualization techniques you learn, to apply them in unique ways to new data. Sometimes, it is precisely this serendipitous application to a data set that reveals underlying information that you would never have noticed if you had not used a particular visualization tool in that way. Remember they called it Data Explorer, not Data Presenter of Preconceived Notions.