Tute M01 Inspect Zpts ASC

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    Introduction

    As of TUFLOW build 2011-09-AF, TUFLOW can directly read elevation data from a Digital Elevation Model (DEM). The format recognised by TUFLOW is ESRI ASCII Grid, this is an open text format that is recognised by a wide range of software including Vertical Mapper and Encom Discover (MapInfo), ArcGIS, QGIS.

    For this tutorial a DEM has been provided in this format with a .asc extension, however, the .txt extension is also used for this file format. The process of creating a DEM in these packages is beyond the scope of this tutorial, for details on DEM creation please see the relevant documentation for your GIS package.

    Method

    1. Copy or move the DEM (dem_m01.asc) from the Module Data Module_Data\DEMs\Text\ into the TUFLOW\model\grid\ folder. TUFLOW can read the DEM from the module data if desired, however, for clarity this is included in the TUFLOW\model\ directory.
    2. Open the current TGC file M01_5m_002.tgc in your text editor.
    3. Assign a value default value for the Zpts (above any expected flood level), by adding the following line to the TGC file.
      Set Zpts == 75
    4. To assign elevations to the Zpts using a DEM, the following command is used.
      Read GRID Zpts == grid\DEM_M01.asc
    5. Save the modified TGC file.

    Conclusion

    We have modified the TGC file to read the Zpt elevations from a DEM dataset. Please return to the tutorial model module 1 page where the next step is to define the active areas.