GIS Platforms

The majority of input data to TUFLOW is via GIS layers. TUFLOW creates templates of the layers, that are then edited, modified and managed within a GIS environment. Existing GIS layers are also readily used (eg. land-use layers, pipe networks).

The user will require a GIS that supports the MapInfo Interchange .mif format or the ArcGIS .shp format. Other formats will be built in depending on demand from users. 3D surface modelling software is also required to extract ground elevations and bathymetry, and for displaying, contouring and interrogating flood surfaces created by TUFLOW. MapInfo with Vertical Mapper or Discover 3D, ArcGIS with Spatial Analyst/3D Analyst (www.esri.com), and free open source products such as SAGA (www.saga-gis.org) are examples of GIS/3D TUFLOW model development environments.

Several, small text files in free-form style are used to convey and control information flow, and setting of options. These text files are very flexible and are similar to writing a macro. The preferred text editors are UltraEdit (www.ultraedit.com) and TextPad (www.textpad.com), which offer advantages such as colour coding, easy access from one file to another, and can be set up to run TUFLOW. Spreadsheet software (eg. Microsoft Excel) is used to manage tabular data such as BC databases and cross-section profiles in an unstructured, user designed and controlled approach.

TUFLOW output is fed back into the GIS as layers and 3D surfaces for producing high quality report figures and maps, and for interrogating results (for example, providing peak flood levels at individual properties).

In addition to using the GIS platform, the SMS (www.aquaveo.com) and WaterRIDE (www.waterride.net) softwares display TUFLOW output. These products are used to animate simulations and interrogate model results. Both 1D and 2D domains can be viewed and animated together.

Using a GIS enhances the capacity to model, offers greater flexibility, and is a powerful modelling environment. This option also keeps overall software costs to a minimum. GIS users are also able to tap into the full functionality of TUFLOW and have immediate access to all new features when new versions of TUFLOW are released.

MapInfo is historically the favoured GIS used for creating, managing and viewing TUFLOW models. It has a number of advantages over other GIS platforms including ease of use, cost, robustness, speed, mixed object types (eg. points and lines) and symbology in the one layer, and is readily customised (for example, see miTools). MapInfo, however, does not have the depth of features compared with, for example, ArcGIS, and is often not a preferred option as a corporate GIS. Many TUFLOW users adopt an approach of using MapInfo for TUFLOW modelling, and use their corporate GIS for final flood mapping and other pre and post processing tasks.

For managing 3D surfaces, MapInfo is well served by Vertical Mapper and Discover 3D. Both of these products are excellent and cover most of the tasks a flood modeller needs. The one exception might be the creation of DTM TINs where advanced TIN functions offered by products such as 12D and ArcGIS 3D Analyst are needed. GIS/TIN software products readily transfer data between themselves so there is rarely an issue with creating the DTM in one package and exporting to Vertical Mapper or Discover 3D. Where there is an issue, one of our free utilities may help (eg. tin_to_tin.exe and 12da_to_from_mif.exe) – see Chapter 11 of the TUFLOW Manual for details.

Many TUFLOW modellers have purchased miTools to streamline and optimise their modelling in MapInfo. Visit miTools for further information.

The TUFLOW Tutorial Model Wiki includes full support for MapInfo with Vertical Mapper and MapInfo with Discover 3D.

ArcGIS is the world’s most popular GIS. It offers a wide range of functionality from high end corporate requirements to end-user needs. ArcGIS is also well supported with its powerful 3D surface modelling products Spatial Analyst (grid based) and 3D Analyst (TIN based) software.

Based on requests by ArcGIS users, the 2010-10 TUFLOW release incorporated recognition of .shp files for reading GIS layers, and the 2011-09 release writes all GIS result and check layers in .shp format. Previously, ArcGIS users had to use the .mif format which was cumbersome to use via ArcGIS. With the full support of .shp files in TUFLOW, ArcGIS is now an excellent option for TUFLOW modelling. The TUFLOW_to_GIS utility has also been enhanced to output .shp files as an alternative to .mif.

Value adding to ArcGIS through offering customised symbology of TUFLOW layers and miTools functionality is planned for the future.

The TUFLOW Tutorial Model Wiki includes full support for ArcGIS.

QGIS (QuantumGIS) and SAGA (System for Automated Geoscientific Analyses) are powerful open source (free) GIS and 3D grid based surface modelling software. QGIS and SAGA primarily use the .shp format for GIS layers, but QGIS readily opens numerous other formats including .tab and .mif. With the 2011-09 TUFLOW release providing full .shp file support these software are now a viable option for TUFLOW modelling. Along with MapInfo and ArcGIS, QGIS and SAGA are being used by TUFLOW developers to proof TUFLOW’s GIS functionality.

Like most grid based 3D surface modelling software, QGIS and SAGA have limited capabilities for producing TINs. Other software such as 12D or ArcGIS’s 3D Analyst maybe required for producing high quality DTMs of the ground surface.

The TUFLOW Tutorial Model Wiki includes full support for QGIS.

TUFLOW modelling using the SAGA open source GIS software.