Probabilistic Forecasting Exploratory Development

Legend Overlay and Management

Hiding Empty Overlay Legends Cheat Sheet

Within AWIPS, legends have been used quite successfully as a user interface device for manipulating the characteristics of overlays. However, anyone familiar with current D2D ensemble capabilities will realize that if several ensemble fields are loaded, legend management becomes very difficult. So one of the goals of this prototyping was to improve that.

Step 1: Start D2D.
Step 2: From Volume->Browser..., load Sources Ensemble->SREF-21, Fields Basic->Height, and Planes Pres->500MB (see below, click on image for full resolution). Minimize the VB.

Step 3: Expand the Legend, by clicking Mouse Button-1 (MB1) on the + on the left side of the Legend.
Step 4: Toggle one item in the Legend off by using MB1.
Step 5: Click and hold Mouse Button-3 (MB3) on a different item in the Legend, a popup window displays; change the Density to zero.
Step 6: Click and hold MB3 over the main display away from the Legend, a popup window displays; select Hide Empty Legends (see below, click on image for full resolution).

Note the toggled off and zero density items in the Legend disappear, and the small gray more appears on the top right side of the Legend (see below, click on image for full resolution).

The reason this capability is there is because at times you do not want the Legend space cluttered with non-viewable overlays.

Step 7: Click on the more text, note the empty overlay items in the Legend come back. Hit the KeyPad Enter key several times. Note that hiding empty legends is now one of the "states of rotation" it cycles to.
Step 8: Put D2D in Hide Empty Legends mode, using either non Legend popup (Step 6) or the KeyPad Enter key. Click on some items in the Legend with MB1 to toggle them off, note that they disappear.
Step 9: Click on the gray more at the top right side of the Legend, note that the items toggled off in Step 8 reappear.

The point here is that when in Hide Empty Legends mode, sometimes toggling can change the relative position of the items in the Legend.

Step 10: Clear the screen.
Step 11: Exit D2D.