Example: Mouse Selection in a Drawing Window

We use the mouse to select objects in a drawing window.   This could be a drawing layer in a map or simply in a drawing window.

Ctrl Means Selection

The Ctrl key used with the mouse is a command to select objects.   By default, Ctrl adds to the selection.

 

 

Ctrl-click on an object to select it.   Each object that is Ctrl-clicked is added to the selection.

 

 

Ctrl-click on a second object and it will be added to the selection.

 

Shift Means Subtract

The Shift key is a command to subtract from the selection.  Shift and Subtract both start with the letter S.

 

 

Shift-Ctrl-click on a selected object to subtract it from the selection.

 

 

Ctrl and Dragging Adds to the Selection

If we press the Ctrl key while clicking and dragging with the mouse, we draw a selection box that selects all objects which touch any part of the box or the region inside the box.

 

 

Press and hold the Ctrl key and click and drag a selection box.   The box cursor appears with a plus + sign to indicate we are adding to the selection. All three objects touch the selection box region so all three will be added to the selection.

 

Shift-Ctrl and Dragging Subtracts from the Selection

Adding the Shift key means to subtract from the selection.

 

 

If all three objects are selected, pressing and holding both the Shift key and the Ctrl key while clicking and dragging a selection box will subtract from the selection all objects that touch the box or the region inside.   The box cursor appears with a minus - sign to indicate we are subtracting from the selection.  

 

 

 In the illustration above the two objects that touched the selection box region were subtracted from the selection.

Restricting to Entirely Within the Selection Box

The default action for selection box commands is to apply them to all objects that touch any part of the selection box or the region within.    Sometimes we would like to apply a selection command to only those objects that fall entirely within the selection box.

 

To do that we use Ctrl and click and drag as with the default command, but we release the Ctrl key before finishing the dragging motion and releasing the mouse key.    This feels weird at first, but after doing it a few times, muscle memory becomes established and the motion becomes very fast and easy.   

 

An example:

 

 

Begin by pressing the Ctrl key and clicking and dragging.   The selection box is shown using a thin, dotted outline like we have seen before.   The selection box cursor includes a plus + sign to indicate we are adding to the selection.

 

 

 

At any time, we can release the Ctrl key, that is, we can stop holding it down, while still keeping the mouse button pressed as part of the click and drag mouse motion.  The selection box instantly changes to a thicker dotted outline.   This indicates that the selection command now applies to only those objects which fall entirely within the selection box.  When we release the mouse button to finish the click and drag motion, only the one object that falls entirely within the selection box will be added to the selection.

 

At any time while we still have the mouse button pressed during the click and drag motion, we can release the Ctrl key or press it again.   Pressing the Ctrl key switches to a thinner selection box, indicating the command applies to any object that touches the selection box region.  Releasing the Ctrl key switches to a thicker selection box, indicating the command applies to only those objects that fall entirely within the selection box region.    The mnemonic for this to help us remember is that a thicker selection box is like a stronger wall, so the selection does not leak out to objects only partially in the selection box region.

Subtracting Entirely Within the Box

The same motion works if we add the Shift modifier to subtract from the selection.

 

 

Begin by pressing both the Shift key and the Ctrl key and clicking and dragging.   The selection box is shown using a thin, dotted outline like we have seen before.   The selection box cursor includes a minus - sign to indicate we are subtracting from the selection.

 

 

 

At any time, we can release the Ctrl key, that is, we can stop holding it down, while still keeping the Shift key pressed and the mouse button pressed as part of the click and drag mouse motion.  The selection box instantly changes to a thicker dotted outline.   This indicates that the selection command now applies to only those objects which fall entirely within the selection box.  When we release the mouse button to finish the click and drag motion, only the one object that falls entirely within the selection box will be subtracted from the selection.

 

See Also

Selection

 

Select Pane

 

Tables

 

Example: Select a Range of Records in a Table - We can select or deselect a range of records between any two records in a table window using fast and easy mouse commands.

 

Example: Combining Selections using the Select Pane - How to use selections to solve a one-off problem casually that would be more difficult to solve rigorously with SQL.   The objective in the example's scenario is to visit a point of tourist interest while travelling.    We will use the Transform pane as well as the Select pane.

 

SQL Example: Using Selection Query Functions - How to manipulate selections within a query.

 

Example: Using Select Pane Templates - A sequence of actions using Select pane templates.

 

Example: Construct JSON String using Select and Transform - Use the Select pane and Transform pane  to manually construct a JSON string using values from other fields in a table. Shows how we can manipulate text to build desired contents in a field.