Matlab GUI Documentation -- 1.2.4 Displaying the Data

Index

1.2.4 Displaying the Data

Each time you use the browser to request data, it will ask how the data are to be displayed. The first thing that happens is that the browser makes a guess as the X, Y, and Z coordinates you want to display. It confirms the guess by presenting a dialog to you Can't exec program: /usr/local/bin/giftext.pl like the one in the figure. Using this dialog, you can select the three coordinates to be displayed from among all the variables returned by the data request.

Using this Display dialog, you can modify your earlier choices, and you can also select the type of display you want (color image, contour plot, quiver plot, and so on), and further select the returned data.

You can call this dialog up with the Data, Plot acquired Rxx button.

The Display Dialog

In some circumstances, the Z data might be returned as a three-dimensional array. To display it, the array must be subsampled. You can do this by typing a Matlab expression right into the Z-data text box. For some datasets, the Matlab matrix transposition operator (') is important to use here. Others might require a matrix sampling. Can't exec program: /usr/local/bin/giftext.pl

The dialog contains the following fields to modify:

Plot Number: This is the number of the plot, assigned and incremented by the browser.
Acquisition Number: Requests for OPeNDAP data are numbered within a Matlab session. Names of data variables from the first request are prefixed with R1_. The second request makes variables with R2_, and so on. This keeps data from being overwritten as requests are made after other requests.
Plot Type: A list of available plot types. These are standard Matlab types.
Plot Data: Depending on the plot type selected, the display dialog will present an assortment of selection lists to set plot parameters.
Display Window: A selection list is presented to allow you to specify whether the plotting should be done in a new window, in the existing browser window, or in a window to be specified.
X-data, Y-data, Z-data, V-data: The data to be plotted must be specified in these fields. If any of these arrays must be trimmed, processed, transposed, or sampled, you can enter valid Matlab expressions to do so in the text boxes. For example, if you have an array that needs transposing, you can type the Matlab array inversion operator (') after the array name.

At the bottom of the display dialog, there are four buttons. Use the Cancel button if you've thought better of the whole thing, and wish to make another data request. The data will still be available inside Matlab, but the browser will skip plotting it. The Plot Selected button will plot the data selected in the dialog. If you want to plot several layers at once, use Plot All, and all the data will be plotted at once. A Next Plot button will appear on the browser window to allow you to flip through the plots.

The Overplot button is a toggle button. When it's activated, the browser will not clear the previous plot when drawing a new one. Click it to activate, and click it again to de-activate this mode.

The Display Dialog, Contour plotting

Several of the plotting modes require different settings. When you select the plot mode, drop-down lists and dialogs will appear to allow these settings. See the figure for an example.

Tom Sgouros, December 21, 2004