Digitizing Elements

Digitizing (or drawing) elements on the Map View can be performed using the various HEC-RAS specific commands (e.g., Draw River Reaches) or generic draw commands (e.g., Draw Polylines).

Digitizing Modes

The following digitizing modes commands are located at the bottom of the application:

  • Enable / disable ortho mode (or press Function Key F8)
  • Enable / disable snap mode (or press Function Key F3)

Map View Digitizing Modes

Curvilinear Digitizing

When digitizing polylines, polygons, and other HEC-RAS elements, the user is provided an option to create curvilinear elements. This option provides a more naturally looking element. The software will fit a cubic spline through the digitized points, as shown below.

NaturalCubicSpline

Once the user has completed the digitizing of the curvilinear element, the software automatically inserts intermediate vertices to represent the curved element using short straight line polyline segments.

While digitizing using the curvilinear option, additional vertices need to be digitized to transition between straight line section and curved section. These additional vertices anchor the straight line section from becoming curved.

Canceling the Digitizing Command

While the digitizing command is active, to cancel the command press the Esc key. The software will cancel the digitizing command.

Undo a Segment during Digitizing

While digitizing an element, press the U key (for Undo) to undo the last segment of the element being digitized. The U key can be pressed multiple times to undo multiple segments of the element while digitizing.

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