Compute coordinates of vector line?












1















I have a set of vector lines (which represent translation vectors for georeferencing).
Based on the layer CRS, how can I compute the coordinates of each line in an attribute table ?



i.e (Xmax-Xmin; Ymax-Ymin) for each line.



I have managed to get the line length with $length in the expression editor but I am struggling with other geometrical parameters.



Edit: I am looking to "store the formula" within the layer. The idea is to keep these values automatically updated with the geometry. (Auto)update should happen if a new line is added or modification of the current geometry is done.






qgis







share|improve this question




















  • 1





    About your recent edition, look at virtual fields (stores the formula but not within the layer). About the $length() function, it calculates the ellipsoidal length, use length( $geometry) instead if you want the planimetric one (probably not so). About the (Xmax-Xmin; Ymax-Ymin) example, it is assumed to be a string of characters because a pair of values can not be attributed to a single numeric field.

    – Gabriel De Luca
    2 hours ago


















1















I have a set of vector lines (which represent translation vectors for georeferencing).
Based on the layer CRS, how can I compute the coordinates of each line in an attribute table ?



i.e (Xmax-Xmin; Ymax-Ymin) for each line.



I have managed to get the line length with $length in the expression editor but I am struggling with other geometrical parameters.



Edit: I am looking to "store the formula" within the layer. The idea is to keep these values automatically updated with the geometry. (Auto)update should happen if a new line is added or modification of the current geometry is done.






qgis







share|improve this question




















  • 1





    About your recent edition, look at virtual fields (stores the formula but not within the layer). About the $length() function, it calculates the ellipsoidal length, use length( $geometry) instead if you want the planimetric one (probably not so). About the (Xmax-Xmin; Ymax-Ymin) example, it is assumed to be a string of characters because a pair of values can not be attributed to a single numeric field.

    – Gabriel De Luca
    2 hours ago
















1












1








1








I have a set of vector lines (which represent translation vectors for georeferencing).
Based on the layer CRS, how can I compute the coordinates of each line in an attribute table ?



i.e (Xmax-Xmin; Ymax-Ymin) for each line.



I have managed to get the line length with $length in the expression editor but I am struggling with other geometrical parameters.



Edit: I am looking to "store the formula" within the layer. The idea is to keep these values automatically updated with the geometry. (Auto)update should happen if a new line is added or modification of the current geometry is done.






qgis







share|improve this question
















I have a set of vector lines (which represent translation vectors for georeferencing).
Based on the layer CRS, how can I compute the coordinates of each line in an attribute table ?



i.e (Xmax-Xmin; Ymax-Ymin) for each line.



I have managed to get the line length with $length in the expression editor but I am struggling with other geometrical parameters.



Edit: I am looking to "store the formula" within the layer. The idea is to keep these values automatically updated with the geometry. (Auto)update should happen if a new line is added or modification of the current geometry is done.






qgis




qgis






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited 3 hours ago







kFly

















asked 9 hours ago









kFlykFly

3061314




3061314








  • 1





    About your recent edition, look at virtual fields (stores the formula but not within the layer). About the $length() function, it calculates the ellipsoidal length, use length( $geometry) instead if you want the planimetric one (probably not so). About the (Xmax-Xmin; Ymax-Ymin) example, it is assumed to be a string of characters because a pair of values can not be attributed to a single numeric field.

    – Gabriel De Luca
    2 hours ago
















  • 1





    About your recent edition, look at virtual fields (stores the formula but not within the layer). About the $length() function, it calculates the ellipsoidal length, use length( $geometry) instead if you want the planimetric one (probably not so). About the (Xmax-Xmin; Ymax-Ymin) example, it is assumed to be a string of characters because a pair of values can not be attributed to a single numeric field.

    – Gabriel De Luca
    2 hours ago










1




1





About your recent edition, look at virtual fields (stores the formula but not within the layer). About the $length() function, it calculates the ellipsoidal length, use length( $geometry) instead if you want the planimetric one (probably not so). About the (Xmax-Xmin; Ymax-Ymin) example, it is assumed to be a string of characters because a pair of values can not be attributed to a single numeric field.

– Gabriel De Luca
2 hours ago







About your recent edition, look at virtual fields (stores the formula but not within the layer). About the $length() function, it calculates the ellipsoidal length, use length( $geometry) instead if you want the planimetric one (probably not so). About the (Xmax-Xmin; Ymax-Ymin) example, it is assumed to be a string of characters because a pair of values can not be attributed to a single numeric field.

– Gabriel De Luca
2 hours ago












3 Answers
3






active

oldest

votes


















3














For QGIS 3.x, the formula in the field calculator is :



'(' || x_max($geometry) || '-' || x_min($geometry) || '; ' || y_max($geometry) || '-' || y_min($geometry) || ')'





share|improve this answer































    3














    You can use the Field Calculator. Open the attribute table of your line layer and select the Open Filed Calculator icon from the toolbar. I use an OSM road layer.



    enter image description here



    In the Field Calculator window create a new column of decimal type, in the Geometry group of functions you can find x_min, x_max, y_min, y_max functions. To create a column with x_range of features use the next screenshot:



    enter image description here



    You can create a column for y_range in a similar way.






    share|improve this answer
























    • Thanks: that is the method I was after but I was missing $geometry to call the proper entity.

      – kFly
      7 hours ago













    • Is there a method to automatically compute these parameters for each line created within this layer as soon as they are created ?

      – kFly
      3 hours ago













    • or update automatically when the geometry is modified ?

      – kFly
      3 hours ago



















    2














    Following J.Monticolo's answer, yet another expression is:



    '(' || bounds_width($geometry) || '; ' || bounds_height($geometry) ||')'





    share|improve this answer
























    • kFly didn't say if (s)he want (Xmax-Xmin) as text or the result of subtraction (q.e.d. width or height). In case of text result, my solution is the good one, in the case of substraction, it's the Kazuhito's one.

      – J. Monticolo
      8 hours ago











    • I want actually the numerical value, but thanks for underlining up this difference

      – kFly
      7 hours ago











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    3 Answers
    3






    active

    oldest

    votes








    3 Answers
    3






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    3














    For QGIS 3.x, the formula in the field calculator is :



    '(' || x_max($geometry) || '-' || x_min($geometry) || '; ' || y_max($geometry) || '-' || y_min($geometry) || ')'





    share|improve this answer




























      3














      For QGIS 3.x, the formula in the field calculator is :



      '(' || x_max($geometry) || '-' || x_min($geometry) || '; ' || y_max($geometry) || '-' || y_min($geometry) || ')'





      share|improve this answer


























        3












        3








        3







        For QGIS 3.x, the formula in the field calculator is :



        '(' || x_max($geometry) || '-' || x_min($geometry) || '; ' || y_max($geometry) || '-' || y_min($geometry) || ')'





        share|improve this answer













        For QGIS 3.x, the formula in the field calculator is :



        '(' || x_max($geometry) || '-' || x_min($geometry) || '; ' || y_max($geometry) || '-' || y_min($geometry) || ')'






        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered 9 hours ago









        J. MonticoloJ. Monticolo

        664112




        664112

























            3














            You can use the Field Calculator. Open the attribute table of your line layer and select the Open Filed Calculator icon from the toolbar. I use an OSM road layer.



            enter image description here



            In the Field Calculator window create a new column of decimal type, in the Geometry group of functions you can find x_min, x_max, y_min, y_max functions. To create a column with x_range of features use the next screenshot:



            enter image description here



            You can create a column for y_range in a similar way.






            share|improve this answer
























            • Thanks: that is the method I was after but I was missing $geometry to call the proper entity.

              – kFly
              7 hours ago













            • Is there a method to automatically compute these parameters for each line created within this layer as soon as they are created ?

              – kFly
              3 hours ago













            • or update automatically when the geometry is modified ?

              – kFly
              3 hours ago
















            3














            You can use the Field Calculator. Open the attribute table of your line layer and select the Open Filed Calculator icon from the toolbar. I use an OSM road layer.



            enter image description here



            In the Field Calculator window create a new column of decimal type, in the Geometry group of functions you can find x_min, x_max, y_min, y_max functions. To create a column with x_range of features use the next screenshot:



            enter image description here



            You can create a column for y_range in a similar way.






            share|improve this answer
























            • Thanks: that is the method I was after but I was missing $geometry to call the proper entity.

              – kFly
              7 hours ago













            • Is there a method to automatically compute these parameters for each line created within this layer as soon as they are created ?

              – kFly
              3 hours ago













            • or update automatically when the geometry is modified ?

              – kFly
              3 hours ago














            3












            3








            3







            You can use the Field Calculator. Open the attribute table of your line layer and select the Open Filed Calculator icon from the toolbar. I use an OSM road layer.



            enter image description here



            In the Field Calculator window create a new column of decimal type, in the Geometry group of functions you can find x_min, x_max, y_min, y_max functions. To create a column with x_range of features use the next screenshot:



            enter image description here



            You can create a column for y_range in a similar way.






            share|improve this answer













            You can use the Field Calculator. Open the attribute table of your line layer and select the Open Filed Calculator icon from the toolbar. I use an OSM road layer.



            enter image description here



            In the Field Calculator window create a new column of decimal type, in the Geometry group of functions you can find x_min, x_max, y_min, y_max functions. To create a column with x_range of features use the next screenshot:



            enter image description here



            You can create a column for y_range in a similar way.







            share|improve this answer












            share|improve this answer



            share|improve this answer










            answered 9 hours ago









            ZoltanZoltan

            3,284917




            3,284917













            • Thanks: that is the method I was after but I was missing $geometry to call the proper entity.

              – kFly
              7 hours ago













            • Is there a method to automatically compute these parameters for each line created within this layer as soon as they are created ?

              – kFly
              3 hours ago













            • or update automatically when the geometry is modified ?

              – kFly
              3 hours ago



















            • Thanks: that is the method I was after but I was missing $geometry to call the proper entity.

              – kFly
              7 hours ago













            • Is there a method to automatically compute these parameters for each line created within this layer as soon as they are created ?

              – kFly
              3 hours ago













            • or update automatically when the geometry is modified ?

              – kFly
              3 hours ago

















            Thanks: that is the method I was after but I was missing $geometry to call the proper entity.

            – kFly
            7 hours ago







            Thanks: that is the method I was after but I was missing $geometry to call the proper entity.

            – kFly
            7 hours ago















            Is there a method to automatically compute these parameters for each line created within this layer as soon as they are created ?

            – kFly
            3 hours ago







            Is there a method to automatically compute these parameters for each line created within this layer as soon as they are created ?

            – kFly
            3 hours ago















            or update automatically when the geometry is modified ?

            – kFly
            3 hours ago





            or update automatically when the geometry is modified ?

            – kFly
            3 hours ago











            2














            Following J.Monticolo's answer, yet another expression is:



            '(' || bounds_width($geometry) || '; ' || bounds_height($geometry) ||')'





            share|improve this answer
























            • kFly didn't say if (s)he want (Xmax-Xmin) as text or the result of subtraction (q.e.d. width or height). In case of text result, my solution is the good one, in the case of substraction, it's the Kazuhito's one.

              – J. Monticolo
              8 hours ago











            • I want actually the numerical value, but thanks for underlining up this difference

              – kFly
              7 hours ago
















            2














            Following J.Monticolo's answer, yet another expression is:



            '(' || bounds_width($geometry) || '; ' || bounds_height($geometry) ||')'





            share|improve this answer
























            • kFly didn't say if (s)he want (Xmax-Xmin) as text or the result of subtraction (q.e.d. width or height). In case of text result, my solution is the good one, in the case of substraction, it's the Kazuhito's one.

              – J. Monticolo
              8 hours ago











            • I want actually the numerical value, but thanks for underlining up this difference

              – kFly
              7 hours ago














            2












            2








            2







            Following J.Monticolo's answer, yet another expression is:



            '(' || bounds_width($geometry) || '; ' || bounds_height($geometry) ||')'





            share|improve this answer













            Following J.Monticolo's answer, yet another expression is:



            '(' || bounds_width($geometry) || '; ' || bounds_height($geometry) ||')'






            share|improve this answer












            share|improve this answer



            share|improve this answer










            answered 8 hours ago









            KazuhitoKazuhito

            15.4k31678




            15.4k31678













            • kFly didn't say if (s)he want (Xmax-Xmin) as text or the result of subtraction (q.e.d. width or height). In case of text result, my solution is the good one, in the case of substraction, it's the Kazuhito's one.

              – J. Monticolo
              8 hours ago











            • I want actually the numerical value, but thanks for underlining up this difference

              – kFly
              7 hours ago



















            • kFly didn't say if (s)he want (Xmax-Xmin) as text or the result of subtraction (q.e.d. width or height). In case of text result, my solution is the good one, in the case of substraction, it's the Kazuhito's one.

              – J. Monticolo
              8 hours ago











            • I want actually the numerical value, but thanks for underlining up this difference

              – kFly
              7 hours ago

















            kFly didn't say if (s)he want (Xmax-Xmin) as text or the result of subtraction (q.e.d. width or height). In case of text result, my solution is the good one, in the case of substraction, it's the Kazuhito's one.

            – J. Monticolo
            8 hours ago





            kFly didn't say if (s)he want (Xmax-Xmin) as text or the result of subtraction (q.e.d. width or height). In case of text result, my solution is the good one, in the case of substraction, it's the Kazuhito's one.

            – J. Monticolo
            8 hours ago













            I want actually the numerical value, but thanks for underlining up this difference

            – kFly
            7 hours ago





            I want actually the numerical value, but thanks for underlining up this difference

            – kFly
            7 hours ago


















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