If an operation is not permitted for the current layer or the current shape, the button for that operation is disabled. If the currently selected layer is not visible, then all of the vector editing buttons will be disabled, except for the "New Layer" button, because vectors cannot be edited unless they are visible.
Some vector editing operations can be performed on more than one current shape, such as Copy, Delete Shape(s) and Move. If the number of current shapes is larger than the value set by the ShapeSaveLimit preference (defaulted at 100), the changes made by these operations are not saved in the undo/redo buffer, so they cannot be undone nor redone. In such cases, the undo/redo buffer is also cleared, so past changes also cannot be undone or redone. However, before any of this happens, the user is always prompted to continue with the operation, so the user may cancel the operation and the undo/redo buffer will not be affected.
In the following descriptions, "clicking" a mouse button means "depress and release" the mouse button.
Break Line - This operation creates two shapes from one. The current shape is modified to include only the vertices from one endpoint to the current vertex. A new shape is created in the vector layer which includes the vertices from the current vertex to the other endpoint.
Close Line - If the first and last vertices of a structure do not have the same position, then a vertex is added to the shape which has the same position as the first vertex.
Copy - Copies and stores the current shapes and their attribute data in the cut-copy-paste buffer. The contents of this buffer are overwritten by this operation.
Copy Shape - The current line is duplicated and placed in the same position as the copied shape. When the left mouse button is depressed and dragged in the image window, the newly duplicated shape is displaced by the distance and in the direction that the cursor has moved, relative to the point where the left mouse button was first depressed. Once the button is released, the duplicated shape takes that position.
Cut - Deletes and stores the current shapes and their attribute data in the cut-copy-paste buffer. The old contents of this buffer are overwritten by this operation.
Delete Shape(s) - The current shape or shapes are removed from the vector layer.
Delete Vertex - The current vertex is removed from the current shape. For shapes with just one vertex (points) the vertex is removed and the shape becomes empty, but is not lost from the layer.
Delete Layer - Removes the currently selected vector layer from the application. A panel asking to confirm the operation is presented since this operation cannot be undone. If the layer has been edited but not saved, the changes will be lost. This operation does not delete the vector segment from the source file.
Insert Vertex - When the left mouse button is depressed in the Main Image Window a vertex is inserted in the current shape between the current vertex and the adjacent vertex which is nearest to the image window cursor. If the current vertex is an endpoint and the cursor is nearer to the current vertex than the next adjacent vertex, the inserted vertex will extend the line.
Join Lines - The current vertex becomes the closest endpoint in the current shape; this is one of the vertices where the join will occur. The second vertex of the join is selected by depressing the left mouse button in the image window near the desired shape. A line will be drawn connecting the current vertex in the current shape with the nearest endpoint in the shape nearest to the image window cursor. Dragging the cursor updates the connecting line. Releasing the mouse button merges the two selected shapes into one.
Move - When the left mouse button is depressed and dragged in the image window, the current shapes are redrawn, displaced by the distance and in the direction that the cursor has moved, relative to the point where the left mouse button was first depressed. This operation is valid for one or more current shapes. If there is more than one current shape to move, a temporary bounding box is drawn to represent the set of shapes being moved. While dragging with the left mouse button depressed, this bounding box is updated instead of the current shapes, but once the button is released, the shapes are moved.
Move Vertex - When the left mouse button is depressed and dragged in the image window, the current shape is partially redrawn with the current vertex moved to the position of the image window cursor. When the button is released, the entire shape is updated.
New Layer - Activates a panel which creates a new vector layer. The panel has fields for a descriptor and georeferencing information which the user must specify in order to create a new vector layer. Selecting the "Accept" button will create a new vector layer according to the specified options. The "Cancel" removes the New Layer panel and returns back to the Vector Editor without creating a new layer.
New Line - After pressing this button, clicking the left mouse button in the image window adds a vertex in a new line at the location of the image window cursor. Additional clicks will add more vertices to the new line. To stop adding vertices to a new line, do one of the following: click the right mouse button, press the <RETURN> key, press the <ESCAPE> key, or select another operation. Note that clicking the right mouse button will end the current line, but will not terminate the New Line operation. The use of the right mouse button enables the user to digitize many lines without moving the mouse outside the work area.
New Point - Depressing and releasing the left mouse button in the image window places a new point in the vector layer positioned at the location of the image window cursor. Clicking on the right mouse button will also insert a new point at the cursor position, but the Vector Editor remains in New Point mode. This allows the user to continue adding points to the vector layer without having to select the New Point button each time. If the user is in this continuous New Point mode, placing a point with the left mouse button will end it. Another way of terminating the New Point mode is by selecting another operation or pressing the New Point button again.
Paste - Pastes the contents of the cut-copy-paste buffer into the current layer. If the contents of the buffer include attribute fields which do not exist for the current layer, these attribute fields are added to the current layer. Should the destination layer already have fields defined then only those fields which have the same field name and type will be transferred. Note that the contents of the cut-copy-paste buffer are not lost between layer changes. If the vectors in the cut-copy-paste buffer are in a different projection from those in the destination layer, they will be reprojected where possible.
Redo - Redoes previously undone operations. This operation can be performed multiple times (depending on how many times "Undo" is performed). This operation also stores changes in the undo-redo buffer, so when the buffer is cleared by certain operations (a warning is given before this happens), the changes are lost and cannot be redone.
Repaint - Repaints (redraws) the entire image window. This is used to refresh the image window.
Rotate Line - When the left mouse button is depressed and dragged in the image window, the current shape is rotated about the current vertex in such a way as to follow the mouse movement.
Select - This operation allows the selection of a set of shapes with a bounding box. To make the bounding box, depress the left mouse button in the image window to define one corner of the box, then drag the mouse to make the opposite corner of the box. Releasing the mouse button defines the opposite corner. All shapes which lie inside or on the bounding box become the current shapes. If the <SHIFT> key is held down while the bounding box is defined, all shapes selected by the box are added to the existing set of current shapes.
Snap To Vertex - Repositions the current vertex to the nearest vertex in a shape that the current vertex does not belong to.
Snap To Line - Repositions the current vertex to the nearest line that the current vertex does not belong to. When possible, the nearest line is determined using the smallest perpendicular distance. This operation also inserts a vertex, in the nearest line, where the current vertex meets it.
Stretch - When the left mouse button is depressed and dragged in the image window, the current shape is rotated and stretched about the current vertex in such a way as to follow the mouse movement.
Undo - Undoes prior vector editing operations. This operation can be performed multiple times to back up through the changes that were made in prior vector editing operations; that is, this operation is not limited to only one level of undoing. The changes that are made through vector editing operations are stored in an undo-redo buffer, so they can be retrieved by an Undo operation. However, some operations cause the contents of the undo-redo buffer to be cleared (a warning is given before this happens), so prior changes are lost and cannot be undone. With the New Line operation, the Undo operation can be used to undo at most the last ten segments of the line, as long as the line has not yet been completed. Once the line has been completed, the entire line is "undrawn" with only one Undo operation.
See Also: GeoEdit, Shape Save Limit