Chopper (lines to vertices) & attributecreator (advanced / prior) should do the job.

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Chopper, max 2 verts.

 

 

Aquire angle of lines. Check if agles are in same relevant quadrant.

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NielsGerrits, that was my idea: explode everything on vertices and calculate test if difference of neighbouring vertices A-(A+1)>0. The problem is that I don't know how to say that in AttributeCreator or Tester. The other problem is that based on start point of polyline the statement might be <0.

 

 

Gio, I didn't think of that but it works: Of course, first you need to do is CoordinateSwapper and then see if the Azimuth goes to different quadrant. Still, there lies a problem where is the start point of polyline. So the trick is to construct a conditional statement for findning different quadrant in one that most of polyline is.

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Hi,

 

 

try the following code in a PythonCaller, it will output one point feature at each vertex of a polyline that has a higher z-value than the previous vertex:

 

 

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import fme

 

import fmeobjects

 

 

class ZDirectionTester(object):

 

    def __init__(self):

 

        pass

 

        

 

    def input(self, feature):

 

        # For each feature, test that Z coordinate values are in

 

        # descending order. If not, output point features on the

 

        # offending vertex

 

        coords = feature.getAllCoordinates()

 

        z_values = ecA2] for c in coords]

 

        for n, z in enumerate(z_values):

 

            if n == 0:

 

                prev_z = z

 

            else:

 

                if z > prev_z:

 

                    point_feature = feature.cloneAttributes()

 

                    point_feature.addCoordinate(*coordsfn])

 

                    point_feature.setGeometryType(fmeobjects.FME_GEOM_POINT)

 

                    self.pyoutput(point_feature)

 

                prev_z = z

 

                    

 

    def close(self):

 

        pass

 

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David

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Hi,

 

 

If you chop the polyline into individual line segments (use a Chopper with Maximum Vertices = 2), you can determine whether each segment is z-ascending or z-descending by comparing z-values of its start and end nodes.

 

You can use two CoordinateExtractors to extract z-values of start and end nodes.

 

 

But I think it would also be enought to compare z-values of start and end nodes of the original polyline, if your purpose is just to determine whether each polyline is z-ascending or z-descending. Because the vertices of a river line basically should be lined in the order of going gradually to either higher or lower.

 

 

Takashi

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