Line Type | Command | Tool | Cursor |
Point to point |
|
| |
Squared |
| ||
Curved |
|
| |
| |||
| |||
Arc |
| ||
Circle |
| ||
Rectangle |
| ||
Digitizing involves defining the location and shape of a feature. You use digitizing tools when you create a feature and when you edit a feature.
When creating, you digitize the feature after you select the acronym and set the attributes. Each feature type has its own requirements:
• Point: A single set of coordinates.
• Sounding: One set of coordinates and a depth.
• Line and area: Several sets of coordinates
You can add coordinates by clicking in the Display window or by typing precise coordinates in the Coordinates window.
Line types
When digitizing lines and areas, you can define the edges using a variety of line types.
Line Type | Command | Tool | Cursor |
Point to point |
|
| |
Squared |
| ||
Curved |
|
| |
| |||
| |||
Arc |
| ||
Circle |
| ||
Rectangle |
| ||
You can change line types while digitizing by selecting a different type. Digitizing continues from the most recent point.
Cursors
When you select a line type, the cursor changes to one of the following:
Cursor | Description |
| Digitize arc. |
| Digitize circle. |
| Digitize curved line. |
| Digitize point-to-point line. |
| Digitize rectangle. |
| Digitize squared line. |
| Digitize point feature. |
| Digitize sounding. |
| Grab an existing edge or follow raster data. |
| Click within edges to digitize an area by reusing an existing area. |
Symbols
These symbols are displayed on the feature as you digitize:
• Large yellow square: The starting node.
• Small yellow square: Vertices.
• Red square: The vertex currently being added or modified.
Shortcuts
The following keyboard shortcuts can help in digitizing:
Key | Purpose |
<Backspace> | Remove the most recent vertex or the last edge grabbed. |
<End> | Complete the digitizing of a line or area. An area is closed automatically. |
<C> or <Home> | Close a line or area. |
<Esc> | Discard the feature currently being added and start from scratch. |
<S> | Snap a vertex of the new feature to a vertex of an existing feature. |
<I> | Intersect the new feature with an existing feature. The existing feature is cut at the snap point and the two features are joined. |
<Space> | When snapping or intersecting, cycle through vertices. If there are multiples vertices at a snap point, press <Space> until the vertex you want is selected. |
Coordinates Window
The Coordinates window displays the coordinates of each vertex in a line or area.
If you define the coordinates by clicking in the Display window, they are displayed in the Coordinates window as you digitize.
You can also use the Coordinates window to precisely specify the coordinates of the vertices or to specify location of vertices using azimuth and distance.
To add a new vertex in the Coordinates window:
1. Double-click in the Latitude column of the first empty row.
2. Type a latitude value.
3. Press <Tab>
The cursor moves to the next column.
4. Type a longitude value.
To add another vertex:
5. Press <Tab> until the cursor moves to the next empty row.
6. Type another new set of coordinates.
Press <End> to complete the feature.
You can switch between digitizing in the Display window and editing or adding coordinates in the Coordinates window.
The Coordinates window can also be used to edit existing features. See Coordinates.
Digitizing can be simpler and more accurate if you:
• Learn the various digitizing cursors.
• Learn the keyboard shortcuts.
• Snap to existing vertices or nodes.
• Enter specific coordinates.
While digitizing:
• To erase the most recently added vertex from a line or area, press <Backspace> or select Line Digitizer > Remove Last or Area Digitizer > Remove Last from the pop-up menu.
• To remove the entire new feature without cancelling the digitize command, press <Esc>.
• To end the new feature, press <End> or select Line Digitizer > End Line or Area Digitizer > Close Area from the pop-up menu.
It is recommended that you save your changes frequently.
