Hi Andreas, Still having issues. I can see the logic of the CASE WHEN END, but I am wondering if the problem is because "Depth" has both a NULL value and a real value. I have tried all sorts of variants and cannot get the NULL depth changed.
Attributes: strike dip rake magnitude quadrant depth 0 null null null null null "Tensional and compressional" null 1 233 38 -96 6.77 Compressional 623 So scanning for Depth=NULL is fine; this is actually all of the event solutions, where the row with the values defines the nodal planes. I have around 2928 events in the shapefile! Can this be solved by scanning for the quadrant attribute, but then how does one specify the value for "Depth". I think if one applies "Depth" NOT NULL it returns 1 I could not find a guide in the documentation for the field calculator that was similar. Cheers Lester On 8 April 2016 at 15:00, Neumann, Andreas <a.neum...@carto.net> wrote: > Hi Lester, > > The field calculator is meant to change "a lot" of values. It will update > all selected records with the new value or calculation (expression). > > With CASE WHEN END you can introduce switches for different rules. > > So - please don't export to Excel. You can do it all with the field > calculator. > > Andreas > > On 2016-04-08 15:28, Lester Anderson wrote: > > Hi Andreas, > > I am trying change a lot of values, if it was a few that is no problem. > > The other option is to export the attribute table as a database and > edit in Excel etc and then join the table in QGIS > > Cheers > Lester > > On 8 April 2016 at 14:23, Neumann, Andreas <a.neum...@carto.net> wrote: > > Hi Lester, > > I thought you want to set the value to 623 where the value was NULL before? > - so just write 623 in the left field after you selected the values. > > Alternatively, you can do without the previous selection and use the > following expression. > > CASE WHEN depth IS NULL THEN 623 ELSE depth END > > Hope this helps, > > Andreas > > > > On 2016-04-08 15:13, Lester Anderson wrote: > > Hello Andreas, > > Selecting the rows where depth = NULL is fine. The field calculator > does not update the depth with the depth where known values are > present. > > Only update selected features is checked, update existing field > checked, with output field set to depth: > Expression: tried just "depth" and also "depth"="depth". > > Have I missed something here? > > Thanks > > On 8 April 2016 at 12:30, Neumann, Andreas <a.neum...@carto.net> wrote: > > Sure. > > It is a two-step thing: > > 1. Select all records where Depth IS NULL. Use the "Select Features using an > expression" button (the Epsilon sign) for that and "depth IS NULL" as an > expression > > 2. Use the field calculator and only update the selected records (the top > checkbox in the field calculator). > > You can find details about the field calculator in the QGIS manual. > > Hope this helps, > > Andreas > > On 2016-04-08 13:18, Lester Anderson wrote: > > Hello, > > I have an attribute table of earthquake data (focal mechanism beach > balls) and need to edit the depth attribute. Each ball is defined by > two rows in the table, eg first ball > > Row_ID Strike Dip Rake Magnitude Quadrant Depth > ---------------------------------------------------------- > 0 NULL NULL NULL NULL Tensional and Compressional NULL > 1 233 38 -96 6.77 Compressional 623 > 2 NULL NULL NULL NULL Tensional and Compressional NULL > 3 68 36 83 5.7 Compressional 39 > etc > > where rows 0,1 and 2,3 represent separate beach balls, so basically it > is a row calculation > > What I need to do is replace the Depth NULL value with the depth 623 > etc for each entry. Is there an easy way of doing this? > > Thanks > > Lester > _______________________________________________ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > List info: http://lists.osgeo.org/mailman/listinfo/qgis-user > Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user > > > > > > > > > > _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: http://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user
