Maps - Context Menus

The main context menu for maps appears when right clicking onto a layer tab. The drawing context menu appears when clicking onto an object in a drawing layer in a map.

 

Context Menu for Map Layer Tabs

 

Visible

Show or hide this layer.

Add

Add a new blank drawing, image or labels component using the map's projection, or launch the Layers dialog to add components from the project pane. The component will be added as a layer just above the active layer tab.

Cut

Windows clipboard cut operation. Copy objects or pixels to the clipboard and delete them from the drawing.

Copy

Windows clipboard copy operation. Copy objects or pixels from this layer onto the clipboard.

Paste

Paste the contents of the Windows clipboard into this layer replacing any selected items.

Paste Append

Paste the contents of the Windows clipboard into this layer.

Delete from Map

Delete this layer from the map. The component will continue to exist in the project pane and in any other maps in which it participates.

Duplicate

Make a copy of this component in the project pane and insert it in the map.

Open

Open this component in its own window. If it is already open in its own window, activate that window.

Open in New Window

Open this component in its own window. If it is already open in its own window, open it again in yet another window.

Rename

Rename this component.

Order

Move layer to top, up, down or to bottom of layer stack.

Opacity

Set the opacity of this layer. See the Layer Opacity topic and the note below regarding the Opacity dialog.

Restrictions

Specify if this layer allows clicking, editing or selecting using mouse commands. See the Layers pane topic for more information on layer restrictions.

Center

Center the active layer in the map window.

Zoom

Zoom to fit the active layer in the map window.

Zoom to Selection

Zoom to fit the selection in the active layer in the map window.

Match

Enabled for image or surface layers. Crop / expand / resample / re-project the active layer so that matches the image or surface specified. Often used to prepare an image so that it is the same size and coordinate system as an another for use as a mask or other purposes.

Register

Move and re-scale this drawing to specify its geographic location. A manual operation that is rarely used. See the Georegistration topic for easier methods.

Project to Map

Re-project this layer's component to match the projection currently used in the map. This is a permanent alteration in the data. When re-projecting an image or a surface, this command will automatically use equal values for the X and Y local scale parameters, thus resulting in geographically "square" pixels.

Transfer Heights

Transfer height values from a surface to a drawing. Available only if the Surface Tools extension has been installed.

Transfer Selection

Transfer selections between components.

Visible Area

Compute area visible from one or more locations in a surface. Available only if the Surface Tools extension has been installed.

Use Projection

Apply the native projection of this component as the projection used by the map.

Properties

View the properties dialog for this layer.

 

Right Click onto an Object (Drawing Layers)

 

Cut

Windows clipboard cut operation. Copies object to the clipboard and delete it from the drawing.

Copy

Windows clipboard copy operation. Copies object onto the clipboard without deleting it.

Paste

Paste the contents of the Windows clipboard into the drawing. Creates new objects in the drawing, replacing any objects that were selected. New objects will be selected.

Paste Append

Like Paste, but does not delete and replace any objects that were previously selected.

Delete

Permanently delete this object.

Duplicate

Duplicate the object. It is wise to immediately move the new object while it is selected. This avoids creating coincident objects that might later cause confusion.

Orthogonalize

Move coordinates to orthogonal grid positions. Used to trim insignificant digits.

Segmentize

Add redundant coordinates to increase the number of coordinates used to define the object. See the Segmentization topic for discussion.

Simplify

Remove coordinates that define the object to simplify the shape of the object.

Center

Pan the view to center this object in the window.

Zoom

Zoom to fit this object.

Coordinates

Launches the Object Coordinates dialog to allow direct editing of the coordinates that comprise the object.

Fields

Launches the Object Fields dialog that shows any table fields associated with this object.

 

Opacity Dialog

 

An alternative to setting layer opacity via the % edit box in the Layers pane is to use the opacity dialog that pops up from the context menu for map layer tabs. Right click onto a layer tab and choose Opacity to open the dialog:

 

images\dlg_opacity.gif

 

The opacity dialog allows interactive setting of transparency by moving a slider bar. Check the Preview box to see the effect in real time. We can also click into the edit box and change the opacity value number.

 

Nomenclature

 

Transparency and opacity are two terms that mean the same concept viewed from different directions. When something is completely opaque it is not at all transparent. When something is perfectly transparent it may be said to have zero percent opacity.

 

Which word is used depends on the discussion. When imagining layers stacked up above each other like transparent sheets it is conceptually clearer to use the word transparency. When discussing a specific percentage of light transmission to be applied via a slider bar in a dialog most applications use the word opacity.

 

The convention in the graphics arts editing software industry is to adjust layer opacity with controls that set a number from 0% to 100% opacity, so that an image with 100% will be fully opaque and not allow any view of an image underneath it. Manifold follows this convention. This convention persists in the graphics arts industry even though the technical implementation of transparency effects is done using an alpha channel within RGBa images where the higher the value of the alpha channel (from 0 to 255) the higher the transparency.

 

One therefore encounters the slight conceptual dissonance of increasing opacity with higher numbers (up to 100%) in dialogs and other user interfaces while the internal data sets use numbers (alpha channel values) in which opacity decreases with higher numbers. Since we rarely set alpha values by hand this is not so bad. Alpha values are normally set using various tools, such as erasers, or masks. In the case of masks, the darker the mask region the lower the alpha value is and thus the higher the opacity. From a casual conceptual view this is very acceptable because it leads to an effect where black regions of masks cause full opacity and white regions of masks cause full transparency. Since we are used to thinking of "white space" as being transparent this works well as a natural mnemonic for the effects of masks.