Topography Modifications in TUFLOW
- 1. Topography Modifications in TUFLOW Mayuresh Padalkar 1
- 2. 1. 2d_zln • To represent levees, flood defences, roads, railways and embankments that obstruct flow. Gullies can also be represented • Command: Read GIS Z Line (thin line) • THIN line modifies ZH, ZU, ZV elevations only if MAX/RIDGE is used but if you use GULLY/MIN, then ZC are connected to give a continuous flow path • Mention GULLY in command line if modelling a creek/watercourse/thalweg • THICK line modifies the whole cell • ADD option adds/lowers the DEM • GULLY option cannot be used along with THICK • Attribute: Elevation • Check: 2d_zln_zpt 2
- 3. 2. 2d_zsh • Useful for any modelling with point, polyline and polygon feature • Command: Read GIS Z Shape • 2d_zsh has all the functionality of 2d_zln and a lot more options/attributes • MAX/RIDGE/RAISE – Only changes a Zpt elevation if Z Shape elevation at Zpt is higher for a polygon/polyline • MIN/GULLY/LOWER – Only changes a Zpt elevation if Z Shape elevation at Zpt is lower for a polygon/polyline • MERGE ALL – ignores elevations from points snapped to the perimeter and merges all perimeter vertices • NO MERGE – Doesn’t merge the perimeter elevations • Attributes: Z (elevations), dZ (change in elevation), Shape Width/dMax (THICK) and Shape Options • Check: 2d_zsh_zpt 3
- 4. 3. 2d_ztin • Triangulation of elevation points and lines (converted to points ultimately) within a polygon (mandatory) • Command: Create TIN Zpts Write TIN • Attributes: Z and dMax (optional and applied only for line and polygon) • Check: 2d_sh_obj 4
- 5. Condition 1: Elevations in txt/csv/xyz • Option 1: 2d_ztin (preferred) 1. Create Points and add it to Map window from *.csv 2. Modify the table structure using Table Structure 3. Polygon shouldn’t be snapped to points • Option 2: 2d_zsh 1. Repeat steps 1 and 3 2. Elevations should be in “Z” attribute 5
- 6. Condition 2: Removal of raised structure • Option1: 2d_zsh (preferred) 1. Draw a polygon along the periphery 2. Leave all the attributes blank • Option 2: 2d_ztin 1. Repeat above steps with proper attribute table 6
- 7. Condition 3: Ponds/Lakes/Reservoir • 2d_zsh 1. Draw a polygon along the periphery with NO MERGE in Shape Options 2. Lines should have an elevation in “Z” with TIN in Shape Options 3. Leave other attributes blank 7
- 8. Condition 4: Raising a polygon with fixed value • 2d_zsh 1. Draw a polygon along the periphery of a building having an elevation in “Z” (0.15m) with ADD in Shape Options 2. Leave other attributes blank • 2d_za 1. Use an empty layer 2d_z__ 2. Draw a polygon giving an elevation 3. Use Read GIS Zpts ADD in command line ADD means it adds to DTM i.e. 100 (DTM elevation in mAOD) + 0.15 (m) = 100.15 (mAOD) 8
- 9. Condition 5: Raising an embankment/pond/area • 2d_zsh (Polygon with points) 1. Draw a polygon with NO MERGE in Shape Options 2. Snap the points to polygon giving an elevation in “Z” 3. Leave other attributes blank • 2d_zsh (Polygon only) 1. Draw a polygon with an elevation in “Z” and NO MERGE in Shape Options 2. Leave other attributes blank • 2d_zsh (Polyline with points) 1. Draw a polyline with no attributes 2. Snap the points to polyline giving an elevation in “Z” 3. Optional: Use dMax to specify the width (similar to THICK) eg. Bridge • 2d_zln 1. Draw a polyline giving an elevation 2. Use Read GIS Z Line THICK in command line to modify ZC, ZU, ZV and ZH 9
- 10. Condition 6: Raising/Lowering • 2d_zsh (Polyline with points) 1. Draw a polyline with no attributes 2. Snap the points to polyline giving an elevation in “Z” 3. To the same points use “dZ” to raise (+) or lower (-) 4. Leave other attributes blank • 2d_zsh (Polyline only) 1. Draw a polyline with Z=0.15/(-)0.15 with ADD in Shape Options Note: Mention 1 in Shape Width for THICK in polyline feature 10
- 11. Condition 7: Fill an empty area • 2d_zsh 1. Draw a polygon without any attributes 2. It will use the neighbouring elevations • Set Zpt (Not preferred) 11
- 12. Condition 8: Smooth the topography • Option 1: 2d_zsh with elevations from DTM 1. Draw a polygon without any attributes 2. Snap points to the polygon with Z=-99999 leaving other attributes blank • Option 2: 2d_zsh with desired elevations 1. Draw a polygon NO MERGE in Shape Options 2. Snap the points to polygon giving an elevation in “Z” 12
- 13. References • TUFLOW User Manual Build 2016-03-AE 13
- 14. Thank you!!! 14