Tutorial M02 002 Check Files QGIS GPKG

Introduction

QGIS is used to import the check files and review the modified elevations between both model runs.

Method

This tutorial introduces:

• _DEM_Z
• _sh_obj_check_R
• _DEM_M

Review the check files:

1. Open the file, either:

   • Within the QGIS Browser Panel, navigate to Module_02\TUFLOW\check\M02_5m_002_Check.gpkg and double click the following layer, or

   • M02_5m_002_sh_obj_check_R

   • In File Explorer, navigate to the Module_02\TUFLOW\check folder, drag and drop the M02_5m_002_Check.gpkg into the QGIS workspace and select the layer above.

2. Navigate to the Module_02\TUFLOW\check folder and open the following layers into QGIS:

   • M02_5m_001_DEM_Z.tif
   • M02_5m_002_DEM_Z.tif

3. Use the 'Apply TUFLOW Styles to Open Layers'.
4. Use the 'Apply GPKG Layer Names'.
5. The DEM_Z grid shows the final elevations including any topographic modifications used for the model calculations.
6. The sh_obj_check file displays the TIN triangles created by TUFLOW during the model initialisation and is useful to review for all merge polygons.
7. Use the Profile Tool plugin to compare the DEM_Z files from both model runs.
   
   
   
   
8. The first no merge region raises all elevation points to a single value.
   
   
   
   
9. The second no merge region adds a specified value to all elevation points.
   
   
   
   
10. The merge region used for the farm dam rehabilitation interpolates between all perimeter elevation points.
    
    
    
    
11. The merge region with negative Shape_Option attribute cuts through the embankment. The manually added vertices allow the modification to follow the cross section of the channel.
    
    
    
    
12. Zoom to the landscape files and review the TIN triangles and elevations created by the points, line and region using the merge option.
    
    
    
    
13. Open the following file from the Module_02\TUFLOW\check folder:

    • M02_5m_002_DEM_M.tif

14. Right click on the DEM_M file and select 'Properties'.
15. From 'Render Type', select 'Palletted/Unique Values'.
16. Click 'Classify', five unique values appear referring to the material specified in the 2d_mat_M02_landscape and materials.csv file. Click 'OK'.
17. The DEM_M shows the final material ID values. Change the labels to match the material class as shown below.
    
    
    

Conclusion

• The topographic modifications representing different development sites were assessed using the Profile Tool.
• The DEM_M grid was used to review the land use.

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