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3

You can try the Sort Tool. It can be used to sort by attribute, or more importantly for you, spatially. It allows you to pick which corner (i.e. upper right) to give priority when sorting.


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Just a little bit more of the Lunar Sea answer. Your query it's ok. The problem is that you didn't gave a nome to the geometry column so qgis don't like it. Specify ::geometry ecc... is important but not essential if you know what is it inside your table. It could be possible that you have to specify Multilinestring instead of Linestring. CREATE VIEW ...


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You can do this by evaluating the difference of a polygon's boundary to the symmetric difference between their boundaries, or symbolically expressed as: Difference(a, SymDifference(a, b)) Take geometries a and b, expressed as MultiLinestrings over the next two lines and images: MULTILINESTRING((0 300,50 300,50 250,0 250,0 300),(50 300,100 300,100 250,50 ...


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They're well hidden! I found a directory with archives of shapefiles here. There's some documentation here. It looks like the polygons aren't updated regularly, but you can sign up to the mailing list to find out when they are, according to that document. If you download this archive (33MB), the forecast zones are in land_CLCBaseZone_detail_proj.shp. (The ...


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This is VB.net code for merging lines that share a common end point, the function to call is UnsplitAllLayer0 with utility functions fFlipPC and fJoinPC. First step is to find all the locations where two lines share an endpoint then using those locations go back through and merge both features (extend one and delete the other)... a line may be extended ...


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This is my practice of removing 'parasite' nodes. Original network with links direction shown. Links labelled by FID: Decide where the sink is going to be and flip relevant link if necessary. In this case I picked No 2. Next step I call 'create network'. Script takes selected link, traces all upstream and flips them on the go if necessary. In case ...


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As described in https://www.gaia-gis.it/gaia-sins/spatialite-sql-latest.html the function is used as ST_Line_Interpolate_Point( line Curve , fraction Double precision ) : Point An example that can be tested with SQL command line for example with spatialite-gui. Fraction=0.5 finds the midpoint. SELECT ST_AsText( ST_Line_Interpolate_Point ...


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EDIT: The geom column needs registering in the view public.geometry_columns. This is done by adding '::geometry(linestring, SRID)' to the query: ST_MakeLine(point1.geom, point2.geom)::geometry(linestring, SRID) Thanks @user30184 for the link to the docs


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Hope this works for anyone looking for something similar. This is just the tangent angle. Getting an actual line tangent with this angle is just a matter of using ST_Project(point_in_line, tangent_length, north_heading) or regular vector construction from an angle The inputs are the line you want to calculate the tangent from and a point to project into the ...



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