The Import Cross Section Geometry command is used to import surveyed cross section geometry from a wide variety of file formats. The software will automatically determine where the next cross section starts within the selected file based upon either blank lines contained within the file or a sudden change in direction from one geometry point to the next.
Follow the steps below to use the Import Cross Section Geometry command:
- From the Input ribbon menu, select the Cross Sections menu item and then choose the Import Cross Section Geometry command.
- The Import Cross Section Geometry dialog box will be displayed.
The following sections describe the Import Cross Section Geometry command and how to interact with the above dialog box.
Selecting Cross Section File
The Select Cross Section File section allows the user to select the survey point cross section file. The file needs to be in an ASCII text file format, with either commas, tabs, or spaces delimiting the data fields contained within each row of the file.
The first row within the file that contains 3 floating point numbers is used to start the import cross section process. Whenever a blank line is encountered within the data file or the direction between three adjacent points changes too much, the software interprets this as the start of a new cross section.
The following survey file formats are supported:
- ASC (ASCII text file)
- CSV (Comma-Separated Variables)
- ENZ (Easting, Northing, Elevation)
- NEZ (Northing, Easting, Elevation)
- PENZ (Point, Easting, Northing, Elevation)
- PENZD (Point, Easting, Northing, Elevation, Description)
- PNEZ (Point, Northing, Easting, Elevation)
- PNEZD (Point, Northing, Easting, Elevation, Description)
- PNT (ASCII Point File)
- PTS (ASCII Point File)
- TXT (ASCII Point File)
- XYZ (Easting, Northing, Elevation)
The software will attempt to determine the file format based upon the file extension. However, the user can change the file format to be used after the file is selected.
For reference, Easting = X coordinate and Northing = Y coordinate.
Note that cross section points must overlay only one river reach for this command to operate. In addition, cross sections should not already exist for the river reach that is being used to construct cross sections from the imported points.
Point File Preview
This Point File Preview panel shows the first 100 lines contained within the survey point file. It allows the user to see the contents of the survey point file and allows the user to change the file format to be used for importing based upon preview of the contents. After changing the file format, the column headings change in the Point File Preview panel.
Elevation Data Adjustment
This optional section allows the user to adjust the survey point data elevation values if the elevation data is in a different unit system or needs to have a datum adjustment.
Cross Section River Stationing
This section is used to define the river stationing to be used for the constructed cross sections. The user can define the downstream most cross section river station, along with the river stationing to be used for upstream cross sections.
For the cross sections being constructed, the river stationing value after the decimal point can be defined using the Decimal precision spin control. Cross sections can be numbered using a fixed increment or by using the river chainage along the river reach. The river chainage can be in miles or feet when working in US units, or kilometers or meters when working in metric (SI) units.
Assign Bank Stations
This optional section is used to construct channel bank locations based upon an assumed normal flow depth and a maximum channel width search distance. The software will first determine where the thalweg location is on a cross section by assuming the lowest elevation is the thalweg. It will then move outward from the thalweg until the requested channel depth is reached within the maximum channel width specified.
Assignment of Manning’s Roughness and Flow Lengths
During the construction of the cross sections, the software will automatically assign a default Manning’s roughness for the left overbank, channel, and right overbank areas. In addition, the cross section flow lengths are automatically determined.