Digitising functions

There are several functions that allow entry of strings and points from an external digitising tablet. It is also possible to create new strings by selecting or digitising points from the graphics screen. The digitiser function is flexible enough that it can deal with input from both an external digitiser tablet and the mouse for the creation of new strings.

• Digitise
• Properties
• New point
• New midpoint
• By following a segment
• Start next string
• Start new string
• Reactivate Segment
• Start new segmentre
• Close current segment
• Delete Last Point
• Toggle plane mode
   

• Digitiser tablet

• Initialise tablet
• Show tablet setup
• Locate tablet Menu
• Define Transformation
• Verify Transformation
• Disconnect from tablet
• Configuration
• Communications port
• Message format
• Set tablet scale
• End Configuration
   

• Digitiser options

• Beep for each point
• Enter attributes for each point
• Show point properties
• Auto rescale

When digitising, points are created with X, Y, Z and description values. The X and Y values are determined either by some coordinate transformation setup in the case of an external digitiser or by interpolation from the position on the graphics screen. The Z and description values may be entered for each point or they may be entered once and applied to each point which is subsequently digitised.

The external digitising tablet must be defined before you attempt to use it. See the SSIInstallation and Setup Manual. This documentation assumes that a digitiser has been successfully setup and installed.

To use the digitiser a menu must be placed on the digitiser. The orientation of the menu must be such that it is aligned with the X or Y axes of the digitiser, that is, it may be either vertical or horizontal in orientation. The menu must consist of 15 equal sized boxes which may be either square or rectangular in shape. The labels for each of the boxes are as follows and they must occur in the order shown either left to right or top to bottom.

Digitiser Menu Template

Show Setup

Locate Menu

Digitiser Transformation

Verify Transformation

Next String

New String

End Segment

Close Segment

Delete Last Point

Toggle Point Attributes

Toggle Point Message

Toggle Point Beep

Apply

Cancel

End Digitiser

These menu items for the tablet menu have almost a direct correspondence with the digitiser menu which is displayed on the screen.

Exceptions to this are as follows.

The following items are included on the tablet menu for convenience to minimise the need to operate both the tablet and the keyboard together.

Menu item
Apply
Cancel

The following items on the screen menu are not appropriate to have on the tablet menu.

Menu item
Digitiser
Select
Digitise

Since the two menus are so similar the items will be explained in the order in which they exist on the screen menu.