QGIS Create a TIN: Difference between revisions

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Revision as of 13:38, 22 January 2026 view source Emilie Nielsen (talk \| contribs) Administrators 6,249 edits No edit summary ← Older edit		Latest revision as of 13:54, 22 January 2026 view source Emilie Nielsen (talk \| contribs) Administrators 6,249 edits →Create TIN Mesh
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Line 41: ==Extract Elevation of Polygon Vertices from DEM== Extract elevation at polygon vertices from DEM using the QGIS processing tool 'Drape (set Z value from raster)'. For more information about this tool, please refer to <u>[https://docs.qgis.org/3.3440/en/docs/user_manual/processing_algs/qgis/vectorgeometry.html#drape-set-z-value-from-raster QGIS Documentation - Drape]</u>. <ol> <li> In QGIS, open the DEM file (e.g. '''TUFLOW\model\grid\DEM.tif'''). Line 53: <br> <li>The resulting layer, called '''Draped''' will appear in the QGIS Layers panel. Right click '''Draped''' and select 'Rename Layer'. Rename the layer to '''Draped_Polygon'''. :'''Note:''' This tool assigns elevations to the vertices of the input layer ('''Densified_Polygon''') and outputs a layer of the same type (in this case, a polygon). As such, '''Draped_Polygon''' contains only one attribute. </ol> ==Generate IDW Interpolation== Generate aan IDW (Inverse Distance Weighted) interpolation of the Z shape points layer (points layer containing elevation data), using the QGIS processing tool 'IDW Interpolation'. For more information about this tool, please refer to <u>[https://docs.qgis.org/3.3440/en/docs/user_manual/processing_algs/qgis/interpolation.html#qgisidwinterpolation QGIS Documentation - IDW Interpolation]</u>. <ol> <li> In QGIS, load all Z shape points layers within the polygon extent (e.g. '''TUFLOW\model\gis\2d_zsh_M02_landscape_002_P'''). Line 79 ⟶ 80: ==Extract Elevation of Breakline Vertices From IDW Interpolation== Extract elevation at breakline vertices from '''Interpolated''' using the QGIS processing tool 'Drape (set Z value from raster)'. For more information about this tool, please refer to <u>[https://docs.qgis.org/3.3440/en/docs/user_manual/processing_algs/qgis/vectorgeometry.html#drape-set-z-value-from-raster QGIS Documentation - Drape]</u>. <ol> <li> In QGIS, load the breaklines layer (e.g. '''TUFLOW\model\gis\2d_zsh_M02_landscape_002_L'''). Line 94 ⟶ 95: ==Create TIN Mesh== Create a TIN Mesh using the QGIS processing tool 'TIN Mesh Creation'. This tool will generate a TIN mesh from the above outputs and any Z shape points layers (points layers containing elevation data). For more information about this tool, please refer to <u>[https://docs.qgis.org/3.3440/en/docs/user_manual/processing_algs/qgis/mesh.html#tin-mesh-creation QGIS Documentation - TIN Mesh Creation]</u>. <ol> <li>Go to 'Mesh' in the Processing Toolbox panel and select 'TIN Mesh Creation'. This opens the dialog shown below: Line 104 ⟶ 105: Output format: 2DM Output coordinate system: Use the project CRS. *Output file: Save to the model's '''grid''' folder ('''TUFLOW\model\grid'''). ~~Ensure~~Name the TIN and ensure the file extension is '''.2dm''' (e.g. '''TIN_Mesh.2dm'''). <li>Click 'Run'. Once the tool is finished, click 'Close'. <br> <br>