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Welcome to CivilGEO Knowledge Base
Import HEC-RAS Shapefile Geometry Command
In GeoHECRAS, the user has the ability to import 3D river schematic and cross section data created in GIS or CADD systems using the Import HEC-RAS Shapefile Geometry command. This command allows the user to import GIS shapefile geometry data to construct a large multi-reach HEC-RAS model.
Follow the steps below to use the Import HEC-RAS Shapefile Geometry command:
- From the Input ribbon menu, click the Import Data dropdown menu and select the Import HEC-RAS Shapefile Geometry command.
- The Import HEC-RAS Shapefile Geometry dialog box will be displayed.
The following sections describe how to use the Import HEC-RAS Shapefile Geometry command and interact with the above dialog box.
River Reach Data
This section allows the user to specify which river reaches to import using the polyline shapefile, how to import the data, and what to name the river and reach. By default, this section is disabled (i.e., grayed out). Select the River Reach Data checkbox to enable this section.
This section allows the user to define the river reach data:
- Polyline shapefile
This dropdown combo box allows the user to select which river reaches found in the shapefile to import into the project. - River name ID
This sub-section is used to define the river name to be imported into the project. The following options are provided:- Fixed name: This entry field is used to provide the name of a river when imported into the project. If this option is selected and no value is provided, the following informational dialog box will be displayed on clicking the [Import] button.
- Name attribute: This dropdown combo box is used to select the river attributes name defined in the shapefile as the name of a river when imported into the project. If this option is selected and no attribute is defined in the dropdown combo box, the following informational dialog box will be displayed on clicking the [Import] button.
- Fixed name: This entry field is used to provide the name of a river when imported into the project. If this option is selected and no value is provided, the following informational dialog box will be displayed on clicking the [Import] button.
- Reach name ID
This sub-section is used to define the reach name to be imported into the project. The following options are provided:- Name attribute: This dropdown combo box is used to select the reach attributes name defined in the shapefile as a name of the reach when imported into the project.
- Auto-generate numeric ID: This radio button option causes the software to automatically specify the numeric ID for each reach when imported into the project.
The Insert Junctions for adjoining reaches checkbox option causes the software to automatically insert junctions where there are adjoining reaches. By default, this checkbox option is unchecked and options below it in the section are disabled (i.e., grayed out). Check the checkbox to enable the Dissolve incomplete junctions and Junction reach snap distance options.
The Dissolve incomplete junctions checkbox option causes the software to dissolve redundant junctions from the river reach. By default, this checkbox option is checked.
The Junction reach snap distance entry field allows the user to define the snapping distance for determining the placement of the junctions for adjoining reaches. By default, the software uses a snapping distance of 10 ft (or 3 m). However, the user can enter a different value. Alternatively, the user can click the […] button to measure the maximum distance for snapping adjacent river reaches together from the Map View.
Cross Section Data
This section allows the user to import cross sections and internal boundaries (bridges and inline structures) using a polyline shapefile. By default, this section is disabled (i.e., grayed out). Select the Cross Section Data checkbox to enable this section.
This section allows the user to define cross section data:
- Polyline shapefile
This dropdown combo box allows the user to select the cross sections shapefile to be imported into the project.
River Stationing
This panel is used to define the cross section river stationing to be imported.
This panel allows the user to define the following data:
- River stationing attribute
This radio button option is used to define the cross section attributes name defined in the shapefile as the name of river stations when imported into the project. The user can select the river stationing attribute from the dropdown combo box next to this radio button option. By default, this radio button option is selected.
The Auto correct inconsistent river stationing checkbox is used to fix affected cross section river stationing encountered during GIS attribute assignment so that they are in increasing order moving downstream. - Auto-generate river stationing
This sub-section allows the user to number cross section river stationing based upon river chainage or incrementally.
- Downstream cross section river station
This sub-sub-section allows the user to measure the downstream reach distance in order to assign it as the most downstream cross section river station. The following options are provided:- User defined: This radio button option allows the user to define downstream reach distance in order to assign it as the most downstream cross section river station.
- User river reach downstream length: This radio button option causes the software to use the default river reach downstream length provided in the read-only field in order to assign it as the downstream most cross section river station.
- Cross section river stationing
This sub-sub-section is used to define how the cross section river stations are to increase in value as they move up the river reach. The following options are provided:- Fixed increment: This radio button option causes the cross section river stations to increase by a fixed value defined in the input field next to this option.
- Channel flow length: This radio button option causes the cross section river stations to increase by an increment represented by the channel flow length from the previous (downstream) cross section river station. The user can select miles or feet when working in US units, or kilometers or meters when working in metric (SI) units as units of measure for computing the cross section river station.
- Decimal precision: This spin control allows the user to define the decimal precision used in determining the cross section river stations. By default, the spin control uses a value of 0. However, the user can enter a different value ranging from 0 to 6.
- Downstream cross section river station
Other Attribute Data
This panel is used to define additional cross section geometric data to be imported.
This panel allows the user to define the following data:
- Flow lengths
This sub-section allows the user to define the flow length for the left overbank, channel, and right overbank from the selected shapefile.
The Compute junction flow length checkbox option is used to automatically compute junction flow lengths when inserting a junction into the middle of an existing river reach or digitizing a new reach into the middle of an existing river reach. - Bank stations
This sub-section allows the user to define the left and right bank stations from the selected shapefile. - Manning’s roughness
This sub-section allows the user to define Manning’s n roughness values for the left overbank, channel, and right overbank from the selected shapefile.
Importing Shapefile Geometry
When all the options have been defined, click the [Import] button. The software will then import the GIS shapefile geometry data to construct a HEC-RAS model.
If the selected shapefiles and the project’s CRS are different, the following informational dialog box will be displayed on clicking the [Import] button.
If the same shapefile is used to import different features for the river reaches and cross sections, the following informational dialog box will be displayed on clicking the [Import] button.
