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I have a shapefile that contains the bus route information for a city.

I want to do two things...

  1. Merge all the existing rows so that just one feature represents all the routes...

  2. I have a Points shapefile that overlays this polyline shapefile, I want to break the single polyline shapefile into multiple polylines based on these point locations

i.e. output will be many points each connected by individual shapefiles, preferably I would like each new shapefile to contain information regarding the points it connects.

Can someone suggest a solution preferably in QGIS but ArcGIS works too

6 Answers 6

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In QGIS

1) put the vector in editing mode, select all the features and in the editing toolbar use the "merge features" tool

2) the dynamic segmentation plugin should do the trick

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  • the dynamic segmentation require postGIS , is there an alternative approach ?
    – GeoH2O
    Commented Feb 16, 2012 at 21:38
  • 1
    A linear referencing/dynamic segmentantion tool has been added to QGIS development version in the last days. The developer is working on a GUI then it shold be exposed in the QGIS interface. My guess is that is juts a few days away. Keep checked by installing qgis-dev with osgeo4w (assuming you are on Windows) and keep it updated daily.
    – gioman
    Commented Feb 17, 2012 at 8:45
  • I will keep a watch..
    – GeoH2O
    Commented Feb 17, 2012 at 17:50
  • The link is broken, could you in future posts add some more information?
    – q9f
    Commented Dec 3, 2013 at 12:51
  • faunalia.eu/en/lrs.html
    – gioman
    Commented Dec 14, 2013 at 8:36
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I have just done something similar using Arc GIS. I had a layer of linear features and a fishnet grid that I was using to split the lines, I needed to do this to ascertain the length of the linear features per fishnet polygon. I did it by intersecting the lines and the fishnet grid. This split the lines where the fishnet crossed them per polygon. I could then dissolve the linear features based upon the fishnet polygon ID field and use a statistic type of SUM to give me the total length of the lines within each polygon.

Might not be elegant but it works. Hope it helps.

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In ArcGIS you may use ET Geowizard\Polyline\Split polyline. It gives an option for splitting by reference to other feature class.

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  • Yes but the tool is an add-on
    – GeoH2O
    Commented Feb 16, 2012 at 17:17
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Although this is not QGIS or ArcGIS, another alternative that maybe you can serve is in gvSIG the SEXTANTE tool "Split lines with points layer" (very useful for creating network segments together with "Snap points to layer").

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Here is just another option to use in ArcGIS.

Split Lines at Points:

Splits visible, editable line features at selected point features.

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  • sadly i do not have the license for this tool
    – GeoH2O
    Commented Feb 16, 2012 at 17:28
  • @GeoH2O, Yes this is an older VBA tool, however if you are into programming the code in the .rtf and .bas file could be converting into an ArcGIS Add-In.
    – artwork21
    Commented Feb 16, 2012 at 19:01
  • This is actually a built-in tool at ArcGIS 10, but it requires an ArcInfo level license.
    – blah238
    Commented Feb 17, 2012 at 21:17
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The first step is easy to accomplish using SAGA GIS, ( and if you are on linux you could even try running the modules from Qgis)

Merge all the existing rows so that just one feature represents all the routes... Use modules>lines>Line dissolve I have a Points shape file that overlays this polyline shapefile , i want to break the single polyline shapefile into multiple polylines based on these point locations This seems much harder, especially since your points may not be exactly on the line.

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  • Yes but it is the second step for which i want an elegant solution in a free gis....which i believe is in gvSIG
    – GeoH2O
    Commented Feb 17, 2012 at 20:07

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