What is Spyglass Dicer / Format / Libraries / Transform / Plot / View?

Scientists and engineers employing supercomputers usually see their results as reams of numbers. Well, now these folks have a friend for visualizing their data on the Mac: Spyglass Dicer. Dicer is the third in a set of four packages promised by the Spyglass people, and although it’s useful, it's unfortunately the weakest of the lot so far.

Cutting Up

The first two programs. Spyglass Transform and Spyglass View (see review, October '90, page 72), allow the import, display, and manipulation of data in one- or two-dimensional arrays. Dicer takes the next step by supplying tools for viewing 3-D data. This can be data that varies in three spatial dimensions (x, y, and z) or data that varies with time (or any other independent variable).

Your first task when you use Dicer is to have your data in a format it can read, Its native format, called HDF (Hierarchical Data Format), is a public-domain format for storing data and images, invented by the people at NCSA (the National Center for Supercomputing Applications) at the University of Illinois, Urbana-Champaign. Spyglass also supplies MPW C 3,1 and FORTRAN libraries that you can use to put your data into the correct format. Dicer can import raw binary data (in byte, short-integer, long-integer, floating-point, and double-precision floating-point formats), but you still must order the data correctly and tell Dicer the dimensions of your array. The program also mads a format called netCDF,

Once you've entered your data into Dicer, the program presents you with a graphic of an empty rectangular solid (resembling the comer of an empty room), which represents the volume of your data. Your job is to decide where within this space you want your data displayed and in what colors.

Dicer gives you six tools with which to display your data. Three of them display flat planes or slices through your data (in the x, y, or z planes). The data-cube tool lets you define a rectangular solid within the data. The cutout tool lets you define rectangular-solid holes where data is not displayed and lets you cut comers from data cubes to see what's inside. You can also use cutouts to make holes in data slices. Data cubes, cutouts, and slices can intersect to make complex data displays.

Because you're working on a 2-D screen, creating 3-D rectangular solids is a two-step process. First you define a rectangular region, and then by pressing a key on the numeric keypad, you specify the direction in which you want to stretch the rectangle (left, right, up, down, in, or out). After you’ve stretched the rectangle into a solid, you release the mouse button and the program renders your data cube with colorful data covering its surface. The size of cutouts is defined in the same way data cubes are.

The sixth tool, the tongs, lets you grab, move, or stretch your data slices, cubes, and cutouts. With this tool, you move a data slice or cube (or cutout) by selecting it first (by clicking on it) and then grabbing an edge. The tongs close to let you know you've gotten ahold of the object. Just as in creating the data cube, you use the numeric keypad to govern the direction of movement — to stretch an object, you grab it by a corner and use the keypad to select the direction.

It's obviously difficult to select a cutout (a missing piece), so you have to select all the visible objects and then select Negate All Selections from the menu to select the cutouts. You can also click on the inside face of a data-cube cutout to select the cutout rather than the data cube. This is quite awkward, and I hope Spyglass will rethink its selection methods.

If you like the shapes you've created and want to use them to view another set of data, you can copy them to another data set, scaling the shapes to fit the data.

Dicer has 17 built-in color tables and lets you import those you've built with other Spyglass products. You can also redesign the current table with the paint tool. One unique tool lets you declare certain colors transparent. You do this by painting them out either in the data view or on the color-table display near the bottom of the window. When you select Transparency from the Paint menu, these colors disappear from the data view and you can see through the volume they previously occupied. This is definitely one of the more exciting features of the product.

Snake Eyes

Although Dicer works as advertised, it has some disturbing problems that need to be addressed.

First and foremost, it occasionally crashes, although I couldn’t determine any reproducible causes.

The supplied demo image doesn’t match the tutorial image in the manual, and the tutorial itself jumps around and assumes that different objects are on the screen from those you have if you follow the tutorial in a linear manner.

When Dicer plots data, it normalizes the original numbers in order to fit the 56 possible colors. Unfortunately, it loses track of the data element's original value, so when you point to a place on the screen, you get a value between 0 and 255, not the original value! This derived number is fairly useless.

The program lacks a magnifying-glass tool. You can specify a magnification only when you first bring in the data. The method is awkwardly implemented in a dialog box and offers magnification only in powers of 2.

Although there is a way to rotate a cube and view it from different angles, you almost need a Ph.D, to figure out the dialog box and even then you can rotate the cube only in 90-degree increments. You should be able to grab a cube and arbitrarily rotate it. Spyglass should look at a few 3-D-modeling packages.

There is no way to make oblique slices, which could be important if you plot data that exhibits nonorthogonal phenomena.

There is no facility for animation (although Spyglass does recommend an extremely awkward method for crude animation). This is odd, because Spyglass' other packages support animation.

Although you can copy images to the Clipboard, there is no way to save them to a PICT file (or any other format). As a matter of fact, the File menu has no Save command at all, so when you quit Dicer, you lose all your work.

The Bottom Line

Like Spyglass’ previous packages, Dicer is a powerful program that lets you visualize data in many ways. Unlike Transform and View, though, Dicer never was a public-domain package available from the NCSA. Perhaps if it had been, the folks at Spyglass would have had the user feedback they needed to smooth the program’s rough edges.

Hipschman, Ron. (January 1991). Spyglass Dicer. MacUser. (pgs. 60, 72-73).

Download Spyglass Dicer / Format / Libraries / Transform / Plot / View for Mac

Architecture

Motorola 68K

Compatibility notes

Emulating this? It could probably run under: Basilisk II