Editing Objects

Objects in drawings (areas, lines or points) may be edited in several ways:


·      Use of Interactive Editing to interactively move or reshape objects by interactive dragging of coordinate locations as discussed below.

·      Use of the Edit Toolbar during interactive editing. The edit toolbar provides powerful commands that should be mastered for rapid interactive editing. If not already displayed, the edit toolbar will appear when an object is selected for editing with a CTRL-ALT clicking the object.

·      Use the Object Coordinates dialog to manually edit the coordinate values that define the object.

·      Edit the coordinates of objects (usually points) by changing their values using intrinsic fields in a table.

·      Changing objects using the Transform toolbar or commands such as the Dissolve command.

·      See the Dialog Mode and Visual Tools topic for information on using dialog mode when creating new objects.


Objects are Defined by their Coordinates


Objects in drawings are defined by the coordinates necessary to draw them. Coordinates are simply the numbers for each X and Y position that defines the object.



Consider a drawing that contains an area, a line and three points.



The objects are defined by the coordinate numbers that are used to draw them in a "connect the dots" fashion. The area, for example, is nothing more than a list of five coordinates:


3 7

2 9

3 10

5 9

5 8


Through various clever means Manifold knows how to interpret the above list of coordinates as an area and how to draw the area knowing correctly what is the inside and what is the outside of the area.


We can see the coordinate numbers that make up an object at any time using the Object Coordinates dialog. To use this dialog, right click onto the object in a drawing window and choose Coordinates from the context menu. This launches the Object Coordinates dialog that lists all of the coordinates that define that object.


Although it is not the user-friendliest way of editing objects, if desired we can change the shape of an object by editing the coordinate numbers that define it. To edit an object by changing the coordinates manually, double click into any coordinate value to change it. See the Object Coordinates topic for additional information on this dialog.


Points are easier to edit via coordinates than lines or areas because points are defined by a single coordinate pair. It is conceptually simpler (as well as less keyboarding) to change the location of a point by changing the latitude and longitude of the point than it is to edit a long series of coordinates for a line or an area. We can move points by changing the latitude and longitude of their location as shown in their intrinsic fields in a table. We can move lines and areas by changing their latitude and longitude intrinsic field values in a table; however, doing so moves the entire line or area by moving its centroid and does not reshape the object. See Editing Intrinsic Fields in Tables .


Interactive Editing


Smart Mouse touch selection is used to select objects for editing. An object selected with smart mouse selection will appear with edit handles at each coordinate position that can be used to move or reshape the object. An object chosen for editing is also called the primary selected object.


To select an object as the primary selected object for editing, exit all command modes so that the mouse cursor is in the default arrow form and then CTRL-ALT click on the object to be edited. Edit handles will appear on the selected object at the location of each coordinate that defines the object. We can then move these handles about to change the shape of the object. This is a lot easier than editing coordinate numbers manually via the Object Coordinates dialog.


If we change our minds and we don't want an object to be the primary selected object for editing, we can deselect it by CTRL clicking on it. A CTRL click on an object will toggle the selection status of that object (selects it or deselects it) without changing the selection status of any other object.


Keyboard Modifiers with Smart Mouse Touch Selection


Because a selection may already exist in the drawing when we wish to select an object for editing, smart mouse selection uses keyboard modifiers to allow a richer set of commands.



Equivalent to Select Touch in Replace mode. Click on an object to select it. All other objects are deselected.

Clicking into an empty part of the drawing deselects all objects (with confirmation dialog).


Select an object for editing. Click on an object to select it as the primary selected object.


Invert the selection state of the object without changing the selection state of any other object. Equivalent to Invert mode.


Select the object if it is not yet selected. Does not change the selection state of other objects. Equivalent to Add mode.


Editing Commands


The primary selected object may be moved or changed in shape by clicking and dragging its editing handles:


CTRL-click and drag

CTRL-click an editing handle and drag to move the entire object.


Hold the SHIFT key down while clicking an editing handle and dragging to move the entire current selection, which includes the primary selected object as well as all other selected objects in the active drawing or drawing layer.


The ALT key extends the action of the SHIFT click and drag to all visible layers. Moves all selected objects in all visible layers.

Click and drag

Click an editing handle and drag to move just that handle and so reshape the object.


Holding down the SHIFT key while using CTRL-click to move an ending handle will move only that particular branch in multi-branched objects.


Right-click an editing handle to call up a context menu of additional editing choices. These will allow deletion of coordinates, for example, via the Coordinate sub-menu.

Right-click a segment between editing handles to call up a context menu allowing choices such as adding a new editing handle in that segment.


Editing works by first clicking on the object to make it the primary selected object. Edit handles will appear at the coordinates that define the object. One may then move the entire object or move the edit handles to change its shape. Edit handles may be deleted or added via the commands in the right click context menu. In the case of branched objects (which include islands or holes in area objects), one may delete branches or move them about.


Note that ALT-SHIFT editing will apply to all objects in visible layers, whether or not those objects are visible at that moment due to Zoom range or Layer Opacity settings. It is possible to have a layer be enabled for display (that is, the layer tab was not clicked off) but the objects within that layer not be visible because the layer's Opacity was set to zero percent. Likewise, a layer's objects might not be visible because of a Zoom range setting. In both cases, the ALT-SHIFT editing will still apply to any such invisible objects.


Editing Example


We begin all smart mouse selection and editing by clicking out any mouse command mode. This restores the mouse to the default arrow cursor.



To edit an object we CTRL-ALT-click on it. In this example we CTRL-ALT-click on a triangular area.



The triangular area becomes selected and shows edit handles at the coordinate positions that define the area. This is a simple area that is defined by only three coordinates. A more complex area would show an edit handle at each coordinate that defines it. Larger areas in geographic drawings are often so complex and will have so many edit handles appear that they will blend together in what might appear, at first glance, to be a very wide border.



To move the object, we CTRL-click and keep pressing on any edit handle. Note that the entire outline of the area changes color to show the entire object can be moved.



Without releasing the mouse button, we drag the object to whatever new place is desired. A preview outline shows where the drawing will go.



When we release the mouse button at the new position the object moves to that location.



We can edit the shape of the object by clicking and dragging the edit handles. If we click on the edit handle as shown above the area borders adjacent to the edit handle change color to show that these borders will be altered by moving the edit handle.



Dragging the mouse button shows a preview of how the shape will be altered when this edit handle is moved.



Releasing the mouse button causes the area to change shape to the new position of the edit handle.



To deselect the object, we can either CTRL-click on the object to toggle the selection state off, or we can simply click anywhere in "empty" space in the drawing to deselect all objects.



The result is a reshaped object in a new location.


Selecting Boundary Lines


Beginners at GIS often confuse the idea of an area object with the idea of a region enclosed by a line object. Please read the Drawings topic to clear up this confusion if you have not already done so.


When using smart mouse selection and editing we must click on the object that is to be edited. Suppose we have a line that forms a closed figure. If we wanted to select that line for editing we must click on the line itself and not simply click within the enclosed region as if it were an area object.



Clicking within the enclosed region has no effect except deselecting all items (if we confirm the desired deselection in the dialog that pops up).



To select the line, we must click on the line itself.



This results in the selection of the line object for editing.


Errors of this nature may be avoided by working with the Background off in the layers pane so it is more clear that there are no objects inside lines that happen to form enclosed regions.


Selecting for Editing


We may wish to edit an object within a selection without changing the selection. We can choose objects for editing using smart mouse selection with a CTRL-ALT click without changing the selection state of other objects. Suppose, for example, we have made a selection in a drawing showing Denmark.



CTRL-ALT click on an object to select it for editing as the primary selected object. Here we CTRL-ALT click on the island of Langeland to select it for editing.



When it is selected for editing, edit handles will appear at all coordinates that define the object. Note that the selection state of all other objects has not been changed.



CTRL-ALT click on a different object to select it for editing. Here we CTRL-ALT click on Falster island.



CTRL-ALT clicking on Falster selected it for editing while leaving Langeland selected along with the other objects.


Context Menu Editing Commands


Right clicking on an object selected for editing calls a context menu that contains advanced editing commands. When right clicking on an editing handle, the context menu will also include editing commands for that coordinate.



(Right clicking onto object)


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.


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


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


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


Pan the view to center this object in the window.


Zoom to fit this object.


Launches the Object Coordinates dialog to allow direct editing of the coordinates that comprise the object. Right clicking onto an edit handle and choosing Coordinates will launch the Object Coordinates dialog with that particular edit handle coordinate highlighted.


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




(Right clicking onto an edit handle)


Delete this coordinate. It is not possible to delete the last coordinate necessary to define a point (one coordinate) a line (two coordinates) or an area (three coordinates).

Delete / Split Branch

Delete this coordinate splitting the branch it is in into two branches. Only available when editing a line object. It is not possible to split the branch by deleting its first or last coordinate, the coordinate after the first coordinate or the coordinate preceding the last coordinate.


Duplicate this coordinate. It is wise to immediately move the new coordinate/edit handle to avoid confusion that might be caused by coincident (redundant) coordinates.




(Right clicking onto a segment between edit handles)


Add a new edit handle (coordinate) at the location on the segment that was right clicked. Such a click will not likely be exactly on the line segment, as a click reasonably near a selected object will be interpreted as involving that line even if the click was not exactly on the line segment.

Add on Segment

Add a new coordinate to the object exactly on the line segment nearest to the click.

Add Mid-Segment

Add a new coordinate to the object exactly in the middle of the line segment nearest to the click.




(Right clicking onto a branch or edit handle)


Delete this branch. It is not possible to delete the last branch of an object.


Duplicate this branch. It is wise to immediately move the new branch to avoid creating coincident branches that might later cause confusion.


Enabled only when right clicking onto a coordinate of a line object. Splits the line into two branches at this edit handle. This is an expert-level command that is not the same as splitting the line into two line objects at this position.




(Right clicking onto a segment between edit handles)


Delete this segment. It is not possible to delete one of the last two segments of a line branch or one of the last three segments of an area branch.

Delete / Split Branch

Delete this segment splitting the branch it is in into two branches. Only available when editing a line object. It is not possible to split the branch by deleting its first or last segment.


The above context menu commands should be used in combination with the Edit Toolbar interactive commands.


Changing the Shape of Objects


We can change the shape of objects by moving existing editing handles, by deleting editing handles or by adding new editing handles, which may then be moved to new positions



Suppose we would like to change the shape of a selected area. We would like to add an editing handle, so we right click at the location in the segment where we would like to add the handle.



We choose Coordinate - Add from the context menu to add a new coordinate and editing handle to the clicked segment at the place clicked.



We can now click and drag to move this new editing handle.



For example we can drag it out to the right. A preview line shows the new shape of the area as we drag.



When we release the mouse button at the end of the drag the area changes shape to fit the new location of the edit handle.



To delete a coordinate and associated edit handle we right click on the handle and choose Coordinate - Delete.



This deletes the coordinate at that position. The area will immediately change shape to the shape defined by the remaining coordinates.


Editing Branched Objects


This is an advanced topic. A branched object is one that includes islands or holes as one object. What appear to be separate objects are really the same object but implemented using a complex internal definition comprised of several sequences of defining coordinates all concatenated into one object. Each sequence of coordinates is called a branch.


The usual case is a state or some other geographic region that includes islands. Instead of each island being a separate object, they are all formed into a single area object.



When selecting objects for editing it is easy to see if what appear to be separate objects are in fact a single, branched object. CTRL-ALT clicking on an object in smart mouse selection will cause all the branches to appear with edit handles if they are all different branches of the same object.



In this example, we've CTRL-ALT clicked on one of the three islands and all have appeared with edit handles. This is a certain indication they are all just branches of a single area object.



Right clicking on one of the branches and choosing Branch - Delete from the context menu will delete the branch.



The other two branches will be left unchanged.


The example above shows use an area where multiple branches are used to create islands. Multiple branches are also used to create "holes" within areas. Clicking and dragging an edit handle will move the entire object, including all branches. This default behavior assures that all holes in areas that use branches to define internal voids will be correctly moved.


We can use a CTRL-SHIFT click on an editing handle and drag to move individual branches, whether they are used to represent islands or holes.



Suppose we have a rectangular area with an internal, triangular hole. The hole is a separate branch from the outer border of the area.



We can CTRL-ALT click on the area to make it the primary selected item so that edit handles appear. We can then CTRL-SHIFT click and drag on an edit handle of the internal hole to move just that branch.



While dragging, a preview will show us how the branch is being moved.



When we release the mouse the branch will move to the new position. In this case, we have moved the position of the hole in the area.


Note that we could use the same CTRL-SHIFT -click and drag on an edit handle to move the relative positions of the "islands" in the previous example.


Moving Objects by Changing Intrinsic Fields


Manifold tables can show intrinsic fields that are computed from the object, such as the position of the center of the object. See the Editing Intrinsic Fields in Tables topic for a discussion of how we can move objects by editing their locations as they appear in intrinsic fields in a table.


Keyboard Zoom Commands during Selection and Editing


When making selections or editing objects (such as inserting areas using the Autocomplete feature) we will often want to zoom in or out in the middle of a selection or editing command. Use the + and - keys on the keyboard to do so. Usually the + and - keys in the numeric keypad are used.



"Plus" key: Zoom in at the current tool position.


"Minus" key: Zoom out at the current tool position.


The current tool position is the position of the mouse at the time the + or - key is pressed. When editing, using these keys allows us to easily zoom into a desired location, make a few precise clicks and then zoom back out and proceed at the usual scale.




See the Selection in Drawings topic for additional information on smart mouse selection.


This topic discusses interactive editing of objects using the mouse. However, as a reminder for the reader we should note the following when using non-interactive editing methods such as transform operators or menu commands.


Many editing / transformation operations in drawings (see the Transform Toolbar - Drawings and Drawings - Dissolve topics, for example) will create new objects from existing objects. When new objects are created from existing ones the system must know how to transfer data attribute fields from the existing objects into the new objects. The Transfer Rules dialog in tables sets forth the rules to be used for each particular column.


See Also


Drawings - Object Coordinates

View - Structure

Edit Toolbar