Offset Polyline Command

The Offset Polyline command is used to make a copy of a selected polyline using an offset distance on a specified side of the selected polyline. The user can offset a polyline to create a new polyline whose shape is parallel to the original polyline. Furthermore, the tool allows the user to create multiple offsets of a selected polyline where all offset polylines will be separated by a standard distance.

Note that the users can offset any polyline in their model, for example, a river reach or a cross section. While doing so, the new offset polyline will be placed on the Default Drawing Layer.

Follow the steps below to use the Offset Polyline command:

1. From the Map Edit ribbon menu, select the Offset Polyline command.
   
2. The Offset Polyline dialog box will be displayed.
   

The following sections describe the Offset Polyline command and how to interact with the above dialog box.

Offset Polyline Options

This section allows the user to select an existing polyline and define an offset distance to make a copy of this selected polyline.

The following entries are provided in this section:

1. Pick polyline
   The user can click the [Pick] button to select an existing polyline from the Map View. After selecting the polyline, the status of the Pick polyline read-only field will change from Not Selected to Selected. Note that if a polyline was already selected prior to running this command, then the read-only field will display the status as Selected.
   
   The user can click the [Clear] button to cancel any previous selection and redo the entire process.
   
2. Offset distance
   This field allows the user to define the offset distance at which the copy of the selected polyline will be created. The user can either enter the distance manually or click the [Pick] button to measure the distance from the Map View.

Placing Offset Polylines

The Place Offset Polylines section allows the user to create the offset polylines on either side of the selected polyline.

Click the [Place] button, and the dialog box will temporarily disappear. The user can then select a point on either side of the selected polyline to place the offset polylines.

Once finished, press the [Enter] key or right-click and select Done from the displayed context menu. The user will be returned to the Offset Polyline dialog box, and the Place polyline read-only field will display the number of polylines placed on the Map View.

Note that after the first offset polyline is placed, the software remembers the originally selected polyline (i.e., selected under the Offset Polyline Options section) and allows the user to place the subsequent offset polylines on either side of the selected polyline.

Map Layer Details

Consider defining the data for this section before placing offset polyline on the Map View. This section allows the user to create a new general drawing layer or a GIS layer for the offset polylines. By default, the software places the offset polylines in the Default Drawing Layer. When creating a GIS layer, the polylines are saved as a shapefile.

The following entries are provided in the section to define the type and name of the map layer:

1. Layer type
   This dropdown combo box defines the type of layers that can be created. The following options are provided.
   • Drawing
     This option is used to draw a vector entity of the offset polyline. This type of layer is identical to the Default Drawing Layer that is defined in the Map Data Layers. By default, this option is selected.
   • GIS
     This option is used to create a GIS layer for creating a shapefile of the offset polylines. This data is stored within an external shapefile.
2. Layer name
   This dropdown combo box defines the layer name that will be displayed in the Map Data Layers panel. Duplicate layer names are not permitted.

GIS Layer Details

This section is enabled when the user selects a GIS layer type. Otherwise, these options are not available.

The Directory field defines the path and name of the shapefile to be created. The user can click the […] browse button to select the shapefile directory and file name.

The Schema definition data table allows the user to define the fields to include for the shapefile layer.

This data table requires the following data:

1. Field Name
   This data column is used to define the field name to add to the shapefile layer.
2. Field Type
   This dropdown combo box is used to select the data type of the field defined above. The following data types are provided:
   • Floating Point
   • Integer
   • Text
   • Date
3. Width
   This spin control button is only available for text field types and has a default value of 80. This spin control can range from 1 to 255. Any strings longer than the field width that do not fit into the field format will suffer truncation.