Differentiate between line ending within polygon and line passing all the way through polygon - QGIS





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I have a line file and a polygon file in QGIS.



Primarily I am looking for any polygon that has a line intersecting it - easy, sorted.



From these intersects, I then want to pull out just the polygons that have a line going all the way through them and ignore those where the line ends within the polygon. See the below diagram for an explanation: I only want polygons 2 and 3.



Example



Does that make sense? I haven't managed to find any predefined tools thus far.










share|improve this question































    3















    I have a line file and a polygon file in QGIS.



    Primarily I am looking for any polygon that has a line intersecting it - easy, sorted.



    From these intersects, I then want to pull out just the polygons that have a line going all the way through them and ignore those where the line ends within the polygon. See the below diagram for an explanation: I only want polygons 2 and 3.



    Example



    Does that make sense? I haven't managed to find any predefined tools thus far.










    share|improve this question



























      3












      3








      3








      I have a line file and a polygon file in QGIS.



      Primarily I am looking for any polygon that has a line intersecting it - easy, sorted.



      From these intersects, I then want to pull out just the polygons that have a line going all the way through them and ignore those where the line ends within the polygon. See the below diagram for an explanation: I only want polygons 2 and 3.



      Example



      Does that make sense? I haven't managed to find any predefined tools thus far.










      share|improve this question
















      I have a line file and a polygon file in QGIS.



      Primarily I am looking for any polygon that has a line intersecting it - easy, sorted.



      From these intersects, I then want to pull out just the polygons that have a line going all the way through them and ignore those where the line ends within the polygon. See the below diagram for an explanation: I only want polygons 2 and 3.



      Example



      Does that make sense? I haven't managed to find any predefined tools thus far.







      qgis select-by-location






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited yesterday









      Taras

      2,2903729




      2,2903729










      asked yesterday









      JClarksonJClarkson

      426




      426






















          1 Answer
          1






          active

          oldest

          votes


















          5















          Tested on QGIS 2.18




          I can suggest using a "Virtual Layer" through Layer > Add Layer > Add/Edit Virtual Layer...



          Let's assume we have two layers, namely "lines_test" and "polygons"



          Input



          With using this query you may achieve the result you are looking for.



          SELECT *
          FROM polygons
          WHERE polygons.id NOT IN (
          SELECT polygons.id
          FROM polygons, lines_test
          WHERE ST_Within(ST_StartPoint(lines_test.geometry), polygons.geometry) OR ST_Within(ST_EndPoint(lines_test.geometry), polygons.geometry)
          )


          Output





          References:




          • PostGIS – Opposite of ST_Within


          • Chapter 8. PostGIS Reference | 8.5. Geometry Accessors


          • Documentation “Join Attributes by Location” QGIS 2.18







          share|improve this answer


























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            1 Answer
            1






            active

            oldest

            votes








            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            5















            Tested on QGIS 2.18




            I can suggest using a "Virtual Layer" through Layer > Add Layer > Add/Edit Virtual Layer...



            Let's assume we have two layers, namely "lines_test" and "polygons"



            Input



            With using this query you may achieve the result you are looking for.



            SELECT *
            FROM polygons
            WHERE polygons.id NOT IN (
            SELECT polygons.id
            FROM polygons, lines_test
            WHERE ST_Within(ST_StartPoint(lines_test.geometry), polygons.geometry) OR ST_Within(ST_EndPoint(lines_test.geometry), polygons.geometry)
            )


            Output





            References:




            • PostGIS – Opposite of ST_Within


            • Chapter 8. PostGIS Reference | 8.5. Geometry Accessors


            • Documentation “Join Attributes by Location” QGIS 2.18







            share|improve this answer






























              5















              Tested on QGIS 2.18




              I can suggest using a "Virtual Layer" through Layer > Add Layer > Add/Edit Virtual Layer...



              Let's assume we have two layers, namely "lines_test" and "polygons"



              Input



              With using this query you may achieve the result you are looking for.



              SELECT *
              FROM polygons
              WHERE polygons.id NOT IN (
              SELECT polygons.id
              FROM polygons, lines_test
              WHERE ST_Within(ST_StartPoint(lines_test.geometry), polygons.geometry) OR ST_Within(ST_EndPoint(lines_test.geometry), polygons.geometry)
              )


              Output





              References:




              • PostGIS – Opposite of ST_Within


              • Chapter 8. PostGIS Reference | 8.5. Geometry Accessors


              • Documentation “Join Attributes by Location” QGIS 2.18







              share|improve this answer




























                5












                5








                5








                Tested on QGIS 2.18




                I can suggest using a "Virtual Layer" through Layer > Add Layer > Add/Edit Virtual Layer...



                Let's assume we have two layers, namely "lines_test" and "polygons"



                Input



                With using this query you may achieve the result you are looking for.



                SELECT *
                FROM polygons
                WHERE polygons.id NOT IN (
                SELECT polygons.id
                FROM polygons, lines_test
                WHERE ST_Within(ST_StartPoint(lines_test.geometry), polygons.geometry) OR ST_Within(ST_EndPoint(lines_test.geometry), polygons.geometry)
                )


                Output





                References:




                • PostGIS – Opposite of ST_Within


                • Chapter 8. PostGIS Reference | 8.5. Geometry Accessors


                • Documentation “Join Attributes by Location” QGIS 2.18







                share|improve this answer
















                Tested on QGIS 2.18




                I can suggest using a "Virtual Layer" through Layer > Add Layer > Add/Edit Virtual Layer...



                Let's assume we have two layers, namely "lines_test" and "polygons"



                Input



                With using this query you may achieve the result you are looking for.



                SELECT *
                FROM polygons
                WHERE polygons.id NOT IN (
                SELECT polygons.id
                FROM polygons, lines_test
                WHERE ST_Within(ST_StartPoint(lines_test.geometry), polygons.geometry) OR ST_Within(ST_EndPoint(lines_test.geometry), polygons.geometry)
                )


                Output





                References:




                • PostGIS – Opposite of ST_Within


                • Chapter 8. PostGIS Reference | 8.5. Geometry Accessors


                • Documentation “Join Attributes by Location” QGIS 2.18








                share|improve this answer














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                share|improve this answer








                edited yesterday

























                answered yesterday









                TarasTaras

                2,2903729




                2,2903729






























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