To see any of the visual outputs of GRASS, one must first begin by diplaying a monitor. As usual in GRASS, it may be done either by using the Display Manager or by entries at the command prompt in the Bash terminal.
The technical documentation for the control of monitors is that for GRASS module d.mon.
We will first open a monitor using the Display Manager.
Before we do this, the user must be cautioned that the red "X" in the upper corner of a monitor must NOT be used to close a monitor. This will take a bit of "getting-used-to" by Windows users.
In the Display Manager, start display monitor x0, by clicking menu items in this order: Display => Start displays => x0
By clicking on the blue top bars and dragging, your desktop would look much like this:
CLICK TO ENLARGE
If you are running GRASS 6.1, for displays x0 through x6, we could have accomplished the above another simpler way by merely left-clicking on the "x0" button at the left end of the third row on the heading of the Display Manager. However, this is a new feature and may not yet be stable.
In the Display Manager, stop display monitor x0, by clicking menu items in this order:
It is possible to simultaneously exit completely out of GRASS and simultaneously close all open display monitors by entering "exit" at the command prompt in the Bash window, and pressing Enter, but it is best to close the monitors individually using menu choices.
We will now use the Bash command line to open display monitor x0.
At the command prompt, type
The d.mon graphical screen will appear:
This is the screen that you could have obtained from the Display Manager menu by clicking on:
Click (and hold) on the slider bar on the right and pull it down to the bottom.
We really did not need this listing simply to start a single monitor, but when you have a number of monitors open, this listing will be useful to let you know what is available.
If you have clicked on the middle (resize) button on the upper right in order to see the full list of available monitors, click on it again to return it to its normal smaller size.
Use the slider on the right so that you may see the lower part of the screen. The button for "List all monitors (with current status)" is still selected (as indicated by it's button being red rather than gray). Click it again to unselect it (it's button will turn gray). Click the "Clear" button on the bottom. You will see that this only clears the text display area at the bottom. It will not clear any entries you have made in the various entry areas.
Use the slider bar on the right, and slide it up (by click & hold & drag). Most controls for the d.mon graphical screen will be what you are used to in Windows. This is very much different from that which was allowed in the Bash text form we used to enter GRASS.
Click on the entry field labelled "Name of the graphical monitor to start (string optional)". Enter:
Press the "Run" button. Display monitor x0 will be displayed and the d.mon screen will look like this:
There is no particular need to clear the text field, but we will do it so that you can see that it affects only the text display window and nothing in the entry fields. Press the "Clear" button".
We now want to close display monitor x0.
First we must clear "x0" from the "start" field, because when the "Run" button is pressed, d.mon performs all the items entered in any of the entry fields. Select the text "x0" in the "start" field and delete it, leaving it empty.
Click on the entry field for "Name of graphics monitor to stop (string, optional)"
Click on the "Close" button.
We have now opened display monitor x0 two different ways:
There is yet another way to start display monitor x0, perhaps a bit old-fashioned, but a fairly good way to do the job with a few keystrokes.
To close the monitor using this approach, at the Bash command prompt, type:
So we have learned 3 reliable ways to start a diplay monitor, and know about another way that will be available with the next release of GRASS.
In the Display Manager, use menu commands:
In the Bash window, at the command prompt, type: