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How to plot a line from a text file when all the Y coordinates are in a row followed by all the X coordinates in a row?

paul_m
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I have a series of text files that I am trying to create lines from. Each row in the text file has the number of vertices followed by the Y coordinates for all the vertices and then the x coordinates for all the vertices (see example below)

3,41.1380602942863,41.1378946727126,41.1378187626848,-111.856708809171,-111.857316620769,-111.857869454434

Does anyone know how I could break these up into an X,Y format to use something like the LineBuilder to create lines?

Thanks!

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Best answer by ebygomm 23 June 2020, 23:33

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ebygomm
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One possible way to get pairs of coordinates

Split into a list by the comma, count the length of the list, explode the list into parts, discard the first item in the list (the number of coordinates), create an x attribute if the element index is less than or equal to half the element count -1, create a y attribute if the element index is more than half of the element count -1, use a modulo counter to assign a coordinate index, aggregate together to get coordinate pairs

You could then create points and use a point connector make lines

J
Badge +2

Split, explode, filter, count, rename XY, and merge.

 

From there, use a VertexCreator and a LineBuilder to generate the lines.

 

 

 

 

ebygomm
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In reality though, I'd probably use a pythoncaller to create the geometries, something like this

import fme
import fmeobjects

def processFeature(feature):
    #get value, split on comma to get list and remove first value, convert to floats
    mylist = [float(i) for i in feature.getAttribute('value').split(',')]
    #get num coordinates
    numcoords = int(mylist[0])
    #get first n items in list (excluding first)
    y = mylist[1:numcoords+1:]
    #get last n items in list
    x = mylist[numcoords+1::]
    #create list of tuples
    coords = list(zip(x,y))
    #set geometry
    feature.setGeometry(fmeobjects.FMELine(coords))
ebygomm
Rank
Userlevel 1
Badge +21

One possible way to get pairs of coordinates

Split into a list by the comma, count the length of the list, explode the list into parts, discard the first item in the list (the number of coordinates), create an x attribute if the element index is less than or equal to half the element count -1, create a y attribute if the element index is more than half of the element count -1, use a modulo counter to assign a coordinate index, aggregate together to get coordinate pairs

You could then create points and use a point connector make lines

x and y need to be the other way round of course, now I've noticed you say y coords first but same principle

paul_m
Rank
Badge +1

One possible way to get pairs of coordinates

Split into a list by the comma, count the length of the list, explode the list into parts, discard the first item in the list (the number of coordinates), create an x attribute if the element index is less than or equal to half the element count -1, create a y attribute if the element index is more than half of the element count -1, use a modulo counter to assign a coordinate index, aggregate together to get coordinate pairs

You could then create points and use a point connector make lines

Thank you, your response helped a ton! I had multiple rows, so I made a few adjustments:

  1. Added a Counter before the List Exploder
  2. Used the Counter and the coordinate index (Modulo Counter) in the Aggregate group by parameter
  3. Added a Vertex Creator, Sorter (sort by _count and _element_index), and Line Builder (group by Counter)

     

     

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