Revision as of 10:05, 15 July 2013 view source Par (talk \| contribs) Bureaucrats, Administrators 1,003 edits No edit summary ← Older edit		Revision as of 16:02, 17 January 2014 view source Par (talk \| contribs) Bureaucrats, Administrators 1,003 edits →Extract Breaklines from DEM Newer edit →
Line 76: '''"-brkline <gis file in 2d_zsh format>"'''<br> This feature was added to the 2013-06-AA version of the utility.<br> Extracts elevations from a DEM for breaklines in the 2d_zsh format. This GIS input should have four attributes, z, dz, width and shape_options, as described in the TUFLOW manual. For the utility ~~only~~ the ~~width~~'''dz''', '''shape_width'''and the ~~shape options~~'''shape_options''' are used. Valid ~~options~~shape_options are "Max" and "Min" or blank (average used). The utility will extract an elevation at each <u>vertex</u> along the line. Depending on the line width and DEM cell size, the following methods are used:<br> * If the width is set to 0, the closest DEM value to the vertex is used. If a "shape_option" is specified this is ignored. * If the width is greater than 0, but less than 1.5 times the DEM cell size, the four DEM values surrounding the vertex are used. If max or min is specified in the "shape_option" the max or min of the four values is used. If max or min option is not specified (attribute is blank), the average of the four values is used. * If the width is greater than 1.5 times the DEM cell size, at each vertex a buffer region is created and all non null DEM values within the buffer object are processed. The diameter of the buffer region is equal to the width specified. If max or min option is not specified, the average of the values within the region is used. These buffer regions are outputted as a separate file.<br> If a '''dz''' value is specified (for the 2014-01-AA version or later) this can be used to control the spacing of vertices along the line. If a '''dz''' value of 100 is specified the maximum spacing along the line is 100 (metres or feet), if the existing vertices along the line are greater than 100 (m or ft) apart additional vertices are inserted. The method for inserting additional vertices creates equally spaced vertices. For example, if two vertices along a line are spaced 250m apart and a dz attribute of 100m is specified three line segments of 83.3m will be created as opposed to two segments of 100m and one segment of 50m.<br> '''NOTE:''' For the output GIS file, the '''dz''' attribute is set to 0.0 regardless of the value set in the input field. Example:<br> <li><tt>asc_to_asc.exe -brkline 2d_zsh_breaklines_L.shp DEM.asc</tt><br>

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