+22
Suggestions for an efficient way to determine the local bearing of an arbitrary location along a line. Local bearing is the azimuth angle of a given point to the next vertex in the line.
Bonus points if it iterates easily.
Best answer by gio
View original
+7
Hi,
If I've understood correctly, you want to split the line into 2-vertex segments (Splitter set at 2 vertices) and then use this custom transformer to get the angle. If you wish to assign the result back to the first point in each line segment, use a CoordinateExtractor to extract vertex 0, followed by a VertexCreator replacing the line with a point.
r.
+3
Hi,
Like this?
1. Use chopper on polyline.
2. extract start and end vertices, and name them accordingly. I used S_x,S_y\\
and E_x,E_y.
3. calculate angle.
4. vertexcereator replace mode for startpoints.
5. vertexcreator with following vlaues
x= @Value(S_x)+@Evaluate(@Value(OFFSET)*@cos((@Value(Hoek_)/180)*$(Pi)))
y= @Value(S_y)+@Evaluate(@Value(OFFSET)*@sin((@Value(Hoek_)/180)*$(Pi)))
Offset variable i created to give lenght to a "bearingpointer" (arrow/vector)
Set lenght to you desire.
Now u got your bearing.
(nb. if you use Azimuthcalculator you wont need to extracxt endcoordinates.)
+22
Hi,
If I've understood correctly, you want to split the line into 2-vertex segments (Splitter set at 2 vertices) and then use this custom transformer to get the angle. If you wish to assign the result back to the first point in each line segment, use a CoordinateExtractor to extract vertex 0, followed by a VertexCreator replacing the line with a point.
r.
I don't want the bearing at every vertex, but rather at specific points along the line, which may or may not correspond to an existing vertex.
+22
Hi,
Like this?
1. Use chopper on polyline.
2. extract start and end vertices, and name them accordingly. I used S_x,S_y\\
and E_x,E_y.
3. calculate angle.
4. vertexcereator replace mode for startpoints.
5. vertexcreator with following vlaues
x= @Value(S_x)+@Evaluate(@Value(OFFSET)*@cos((@Value(Hoek_)/180)*$(Pi)))
y= @Value(S_y)+@Evaluate(@Value(OFFSET)*@sin((@Value(Hoek_)/180)*$(Pi)))
Offset variable i created to give lenght to a "bearingpointer" (arrow/vector)
Set lenght to you desire.
Now u got your bearing.
(nb. if you use Azimuthcalculator you wont need to extracxt endcoordinates.)
This gives me some ideas for a starting place. Thanks.
+7
I don't want the bearing at every vertex, but rather at specific points along the line, which may or may not correspond to an existing vertex.
Sorry, I missed that.
OK, start by splitting the line at the points - there are various transformers that do this, but the simplest is probably PointOnLineOverlayer. So:
I also meant Chopper rather than Splitter, but that's academic now...
Hi @gio Would you be able to share your fmw Workspace for this solution please?
Hi @gio , Would you be able to share your fmw Workspace for your solution please?
+3
@johnm
Hi, sure.
It's still on my machine.
The arrow custom is more complex then the main though...linebearings.fmw
Have fun.
Hi @gio, Thanks for this, I would like you to have a look at the one I did to see what you think?
Will get back to you tomorrow with the fmw.
+3
Hi @gio, Thanks for this, I would like you to have a look at the one I did to see what you think?
Will get back to you tomorrow with the fmw.
Hi @gio, Here is another script (2016) for the arrow where the direction angle is provided. Cheers.
+3
Hi @gio, Here is another script (2016) for the arrow where the direction angle is provided. Cheers.
Tx.
My arrow creator is scaled by input (larger line => larger arrows. Also size of arrowhead, shaft etc. are variable.)
It takes input lines, points or just attributes.
I have tried to make it as flexible as possible. It has evolved a bit since I posted above script. Trying to get it to make all kinds of arrowheads.
The createarrow.fmw is fixed size and has hardcoded values.
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