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Tutorial M02 002 GIS Inputs QGIS: Difference between revisions

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Created page with "= Introduction = QGIS is used to create, import and view input data.<br> <br> = Method = Navigate to the '''Module_02\Tutorial_Data''' folder. Copy and save all the below la..."
 
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= Introduction =
QGIS is used to create, import and view input data.<br>
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= Method =
Navigate to the '''Module_02\Tutorial_Data''' folder. Copy and save all the below layers into the ''' Module_02\TUFLOW\model\gis''' folder:
:*'''2d_zsh_M02_landscape_002_L'''
:*'''2d_zsh_M02_landscape_002_P'''
:*'''2d_zsh_M02_landscape_002_R'''
:*'''2d_mat_M02_landscape_002_R'''
 
Create two polygons, one raises the elevation to a set height and another raises the elevation by a set amount. <br>
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<li>Tick the 'Regions' Geometry Type and hit 'OK'. The 2d_zsh file appears in the Layers panel.
<li>Zoom to the area just upstream of the north road crest.<br>
<li>Right click on the ‘2d_zsh_M02_fill_002_R’'''2d_zsh_M02_fill_002_R''' to toggle on Editing and select 'Add Polygon Feature'.
<li>Digitise a polygon similar to below, use the right mouse button to terminate the polygon and an attributes dialog displays. Enter the following data: <br>
:*Z = 45
:*Shape_Option = NO MERGE (assigns a single elevation to all Zpts falling within the polygon without interpolating the edges to the original topography) <br>
<br>
{{Video|name=Animation_M02_GIS_02.mp4|width=1279}}<br>
[[File:Animation M02 GIS 02.gif]]<br>
<br>
<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>
<br>
{{Video|name=Animation_M02_GIS_01.mp4|width=1279}}<br>
[[File:Animation M02 GIS 01.gif]]<br>
<br>
</ol>
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<li>In the Run ID box write 'M02_merge_002'.
<li>Tick the 'Regions' Geometry Type and hit 'OK'. The 2d_zsh file appears in the Layers panel. Zoom to the east side of the model. <br>
<li>Right click on the ‘2d_zsh_M02_merge_002_R’'''2d_zsh_M02_merge_002_R''' and toggle on Editing.
<li>Select 'Add Polygon Feature'.
<li>Digitise a polygon around the depression in the DEM. <br>
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<li>Turn off editing to save the edits.<br>
<br>
{{Video|name=Animation_M02_GIS_03.mp4|width=1279}}<br>
[[File:Animation M02 GIS 03.gif]]<br>
<br>
</ol>
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<li>Tick the 'Regions' Geometry Type and hit 'OK'. The 2d_zsh file appears in the layers panel.
<li>Zoom to the channel where it meets the north road embankment. <br>
<li>Right click on the ‘2d_zsh_M02_cut_002_R’'''2d_zsh_M02_cut_002_R''' to toggle on Editing and select 'Add Polygon Feature'.
<li>Digitise a polygon similar to below, terminate the region and enter the following data in the attributes dialog: <br>
:*Shape_Width = -1<br>
<br>
{{Video|name=Animation_M02_GIS_04.mp4|width=1279}}<br>
[[File:Animation M02 GIS 04.gif]]<br>
<br>
<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>
<br>
{{Video|name=Animation_M02_GIS_05.mp4|width=1279}}<br>
[[File:Animation M02 GIS 05.gif]]<br>
<br>
</ol>
 
Investigate the supplied landscape'''2d_zsh_M02_landscape_002''' files with TIN functionality:
<ol>
<li>Open the files, either: <br>
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:*Select Layer > Add layer > Add Vector Layer and navigate to the ''' Module_02\TUFLOW\model\gis''' folder.
<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. TheWith the 'Shape_Option' attribute 'TIN', the 'dZShape_Width' attribute specifies a sampling distance for the TIN triangles, intermediate sampling points are created at the line vertices and along the line at 'dZShape_Width' intervals.
<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>
<br>
{{Video|name=Animation_M02_GIS_TIN_04.mp4|width=1279}}<br>
[[File:Animation M02 GIS TIN 03.gif]]<br>
</ol>
<br>
Investigate the supplied materials file:
<ol>
<li>Load into QGIS the '''2d_mat_M02_landscape_002_R''' file by, either: <br>
:*Drag and drop the .shp file into the QGIS workspace, or
:*Select Layer > Add layer > Add Vector Layer and navigate to the '''Module_02\TUFLOW\model\gis''' folder.
<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>
<br>
{{Video|name=Animation_M02_GIS_mat_05.mp4|width=1279}}<br>
</ol>
<br>
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:*Three 2d_zsh layers were created to add development sites to the model with different purpose.
:*Complex development site with TIN functionality was supplied and inspected.
:*The 2d_mat layer was reviewed defining the spatial extents for new land use categories.
 
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