4.3 Input Files

4.3.1 Overview

Table 4.6 describes the most common file types used for input to, and output from a TUFLOW FV simulation.

Table 4.6: List of Most Commonly Used Input File Types
File Extension Description
Comma Delimited Files .csv Comma delimited text file/s. They can be opened, edited and saved using text editors or spreadsheet software such as Microsoft Excel.
ArcGIS Shapefile Layers .shp
.dbf
.shx
.prj 		ArcGIS’s industry standard for GIS vector layers.
MapInfo MIF/MID Files .mif
.mid 		MapInfo’s industry standard GIS data exchange format for GIS vector layers.
ESRI Ascii raster grid .asc GIS raster data in the widely used ESRI Ascii grid format.
Binary Float Grid .flt GIS raster data in the binary versions of the .asc format (see above).
Triangulated Irregular Network .tin Triangulated bathymetric/topographic data in the Aquaveo SMS format.
NetCDF .nc Regular gridded or curvilinear gridded data files typically used to as input boundary or initial conditions that vary spatially and temporally. These inputs are often derived from outputs from other models and may include wind fields, atmospheric conditions, short-wave forcing or ocean current forcing.
SMS Mesh File .2dm Flexible mesh topology definition.
TUFLOW FV Restart Files .rst A snapshot of computational results at an instant in time, used for hot-restart of simulations. Output by a previous TUFLOW FV simulation.
TUFLOW FV Transport File _trans.nc Boundary condition file with hydrodynamic fields saved off from a previous TUFLOW FV simulation. Used to run simulations in offline hydrodynamic mode.

4.3.2 Input GIS Layers

The primary types of GIS inputs supported by TUFLOW FV include vector data, raster data, and TINs. The following input formats are supported:

  • GIS vector data layers: Shapefile (.shp) and MapInfo (.mif) formats.
  • GIS raster data layers: Float (.flt) and ASCII (.asc) formats. NetCDF formats are supported for selected inputs, including time-varying meteorological and ocean data grids.
  • GIS TIN data layers: SMS (.tin) format.
  • CSV data files: (.csv) format.
  • NetCDF data files.

The input format is determined solely by the file extension. For example, vector layers using the Shapefile format are identified by the .shp extension, while MapInfo vector layers use the .mif extension.

All GIS layers imported to, or exported from, TUFLOW FV must use a consistent geographic projection. The model projection is initialised using the SHP Projection and MI Projection commands. Multiple input formats may be used within a single model. Where a mixture of input formats is used, a projection command must be specified for each format type.

The default output format for GIS check layers and GIS outputs is determined by the active projection setting. Where more than one projection setting is specified, or where a specific output format is required, the GIS Format command may be used.

4.3.2.1 GIS Vector Layer Commands

Commands containing GIS read from and/or write to GIS vector layers. These commands process the geometry, attribute data, and projection information of the specified input layers.

4.3.2.2 GIS Vector Layer Naming Conventions

TUFLOW FV input file types are described in Table 4.7. The prefixes defined in Table 4.7 provide a consistent naming convention for GIS layers and support effective data organisation and interpretation. The .fvc command Write Empty GIS Files may be used to generate template GIS layers that follow the standard naming convention. This process aligns with the TUFLOW FV model initialisation workflow described in Section 5.2.

Model data input is structured to allow an unrestricted number of data sources. Commands may be repeated within control files to construct a model using multiple datasets. For example, model topography may be defined using a base digital terrain model, supplemented by local survey data, with additional three dimensional elevation lines used to define features such as levees or road crests. Sequential reading of datasets supports layered model construction, traceability of data sources, and quality control.

Table 4.7: GIS Input Data Layers and Recommended Prefixes - 2D Domain
Suggested File Prefix GIS Data Type Description Refer to Section
2d_mat_ 2D Land-Use (Materials) Categories Layers to define or change the land-use (material) types on a cell-by-cell basis. XX
3d_po_ 2D Plot (Time-Series) Output Locations Layer(s) defining the locations and types of time-series output from the 2D domains. XX
2d_sa_ 2D Source over Area Layer(s) defining cell inflow locations. GIS objects with point geometery apply flow to the cell they reside in. GIS objects with polygon geometry will select cells with cell centroids that reside within the polygon boundary. XX
2d_zln_
(2d_zlr_)
(2d_zlg_) 		2D Elevation Lines

Optional 2D or 3D breaklines defining the crest of ridges (e.g. levees, embankments) or thalweg of gullies (e.g. drains, creeks). Ridges and gullies cannot occur in the same layer so 2d_zlr_ is often used for ridges and 2d_zlg_ for gullies.

These files are typically created by renaming the 2d_z__empty file. 		XX
2d_ns_ Nodestring Lines Layers to define the spatial location of boundary conditions, hydraulic struture 1D/2D connections and flux reporting. XX
2d_zn_ Zone Polygons Layers to define 1D/2D hydraulic structure connections when using Linked Zone structure types. XX

4.3.2.3 GIS Vector Layer Attribute Interpretation

TUFLOW FV requires specific attributes to be present in input layers and in a defined order. For example, a material input layer (2d_mat) requires a single attribute that defines the material identifier, whereas a nodestring layer (2d_ns) requires multiple attributes, including the nodestring name and boundary snapping settings. The attributes required for each input layer type are documented in the relevant sections of this manual. Any additional attributes included in a layer are ignored by TUFLOW FV.

The .fvc command Write Empty GIS Files may be used to automate creation of template GIS layers with attribute structures that conform to TUFLOW FV requirements and recommended naming conventions. Template layers may also be generated using the TUFLOW Plugin Import Empty Tool.

TUFLOW FV template files are available from the TUFLOW FV Wiki.

Attribute names documented in this manual or generated by Write Empty GIS Files may change between TUFLOW FV releases to accommodate new functionality. Attribute names themselves are not interpreted by TUFLOW FV. Correct operation requires only that attributes are provided in the required order and with the correct data type, such as character, float, or integer. GIS layers with attribute names that differ from those documented in this manual remain compatible provided the attribute order and types are correct.

4.3.2.4 GIS Vector Layer Object Interpretation

Table 4.8 and Table 4.9 describe the GIS object types that are compatible with TUFLOW FV and how those objects are interpreted during model construction.

Object snapping is used to associate point based data with line and region based data. An example application is the Read GIS Z Line command. TUFLOW FV supports point snapping, end snapping, and vertex snapping. Edge snapping is not supported.

Where objects are intended to be linked, such as a Z line point layer and a corresponding polyline layer, the layers must be snapped and read into TUFLOW FV using a single command. Linked layers are specified on the same command line and separated by a vertical bar character.

Read GIS Z Line == 2d_zln_Breakwater_001_L.shp | 2d_zln_Breakwater_001_P.shp

Table 4.8: TUFLOW Interpretation of Supported GIS Objects
Object Type TUFLOW Interpretation
Point Refers to the 2D cell that the point falls within or a 1D object such as a node or boundary location. Points snapped to the sides or corners of a 2D cell may give uncertain outcomes as to which cell the point refers to.
Line (straight line) Variety of uses including defining a continuous line of 2D cells, 1D channels, to connect objects, alignment of a 3D breakline, linking 1D and 2D elements.
Pline
(line with one or more segments) 		As for Line above.
Region (polygon) For 2D cells either: - Modifies any 2D cell or cell mid-side/corner (e.g. Zpt) that falls within the region. If the command is modifying a whole 2D cell, it uses the cell’s centre to determine whether the cell falls inside or outside of the region. If the cell’s centre, mid-side or corner lies exactly on the region perimeter, uncertain outcomes may occur. Holes within a region are accepted except for polygon objects in shape layers used for TIN boundaries.- Or, only uses the region’s centroid. Examples are the original flow constriction layers (2d_fc) and time-series output locations for some output data types. For 1D: 1D nodes within the region are selected.
Multiple (Combined) Objects In later versions of TUFLOW, multiple point, polyline and region objects are generally accepted (ERROR or WARNING messages are given if not the case).
Table 4.9: TUFLOW Interpretation of Unsupported GIS Objects
Object Type TUFLOW Interpretation
Arc Ignored (do not use).
Collections Not supported. Collections are groups of objects of differing type.
Ellipse Ignored (do not use).
none These objects are ignored and most commonly occur when a line of attribute data is added that is not associated with an object. In MapInfo, this occurs when a line of data is added directly to a Browser Window (i.e. no object was digitised).
Roundrect (Rounded Rectangle) Ignored (do not use).
Rect (Rectangle) Ignored (do not use).
Text Ignored.

4.3.2.5 GIS Raster Layer Commands

Commands containing GRID read and/or write a GIS raster layer. The format is controlled by the file extension (e.g. .flt or .asc).

4.3.2.6 GIS TIN Commands

The Read TIN Zpts command reads from a TIN file. TIN refers to a triangulation file. The format is controlled by the file extension (e.g. .tin).