Tutorial M02 002 GIS Inputs QGIS GPKG: Difference between revisions
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= Introduction =
QGIS is used to create, import and view input data.<br>
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:*Shape_Option = NO MERGE (assigns a single elevation to all Zpts falling within the polygon without interpolating the edges to the original topography) <br>
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<li>Zoom to the south west corner of the grid to digitise the second polygon.
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<li>Turn off editing to save the edits.<br>
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<li>Turn off editing to save the edits.<br>
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:*Shape_Width = -1<br>
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<li>Add more vertices by holding Shift and double click along the upstream and downstream sides of the polygon. By default TUFLOW uses the merge option and the negative Shape_Width instructs TUFLOW to sample the DEM elevation only at the location of the polygon vertices. <br>
<li>Turn off editing to save the edits.<br>
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{{Video|name=Animation_M02_GIS_05.mp4|width=1279}}<br>
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:*In File Explorer, drag and drop the '''M02_002.gpkg''' into the QGIS workspace and select the layers (hold Ctrl to select multiple).
<li>The point layer specifies the elevation with the ‘Z’ attribute. Some of the point are snapped to the line layer setting the elevations along the line.
<li>The line layer assists in the TIN process.
<li>The region layer sets the area over which the TIN functionality takes place. Without points snapped to the perimeter vertices of the region, the elevations are inserted from the underlying Zpt elevations, it uses the default merge option.<br>
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{{Video|name=Animation_M02_GPKG_GIS_002_TIN_02.mp4|width=1279}}<br>
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<li>Load into QGIS the '''2d_mat_M02_landscape_002_R''' file by, either:
:*Within the QGIS Browser Panel, navigate to '''Module_02/TUFLOW/model/gis/M02_002.gpkg''' and double click '''2d_mat_M02_landscape_002_R''', or
:*In File Explorer, drag and drop the '''Module_02/TUFLOW/model/gis/M02_002.gpkg''' into the QGIS workspace and select '''2d_mat_M02_landscape_002_R'''.
<li>Inspect the file:
:*The materials file contains polygons that represent the updated land use due to the topography modifications.
:*The material attribute associated with each polygon is an integer value based on the underlying land use type.<br>
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{{Video|name=Animation_M02_GIS_mat_05.mp4|width=1279}}<br>
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