Talk:QGIS Tips: Difference between revisions
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[[File:QGIS_Points_to_Grid.jpg]]
== Quickly identify top of levees/embankments as Zln ==
The aim of this tip is to show you how you can get the maximum elvations for you levee/embankment.
Install the Sextante plugin for QGIS - See "Alternative method for generating grid from points ". <br>
Draw a line along the top of your levee/embankment. <br>
Select the ''Saga >>> Shapes - Points >>> Convert Lines to Points'' module, fill in as required... <br>
The '''Insert Distance''' option specifies the maximum distance between lines Save a copy of the shape file so you have two point files that are the same.
[[File:QGiS_LinesToPoints.png]]
Using the field calculator, create a new column (I have called it rownum) and assign a rownum to each attribute. Save the shape file and then create a duplicate shape file using the save as. With the duplicate shape file, do the same as above but add 1 to the the rownum, i.e $rownum + 1 as the expression instead of $rownum
[[File:QGiS_FieldCalc.png]]
Merge these two shapefiles, I use the ''Saga >>> Shapes - Tools >>> Merge Shapes Layers'' module <br>
Then convert these points back to a line ''Saga >>> Shapes - Lines >>> Convert Points to Lines'' module. You will want to order and seperate by the column with the rownums <br>
The point of the above is to break your lines into segments. <b>
To be continued..
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