Hi Dodd, Try deviding by 100.0 instead of 100. That way at least you should get decimal results.
Did you try to write the column name like this: "DBH(mm)"/100.0 The way I understand it, this function simply multiplies the symbol base size with the value in the attribute. Best wishes, Anita On Wed, Mar 7, 2012 at 4:51 PM, M.E.Dodd <[email protected]> wrote: > I would like to set the size of point marker in qgis to be controlled by > its data i.e. if the value is larger then the marker itself is larger. > This appears to be possible in e.g. new symbology>advanced>size scale > field, also possible to get to this other ways. However its not clear how > the value in the column affects the size, bigger numbers give bigger > markers but no idea how much bigger or what the numbers in the column mean > for the size, the particular numbers I had in the column gave huge markers > totally unsuitable for the map. > So I then tried to alter the numbers by creating extra column in the > attributes table using the field calculator to divide the numbers by 100. > Firstly this failed because the column title was DBH(mm), it seems the () > are not allowed. so I then changed name of column to dbh (in an external > editor as I could not do it in the attributes table itself) which then > allowed me to divide the numbers by 100. However the new column only > showed one figure so e.g. 180/100 = 1 not 1.8 even though that new column > was width 10 precision 2, actually it showed number 1 whatever values I set > for width and precision. > Not sure if any of this is a bug but these potentially very useful > functions don’t seem to quite work. > > > > -- > The Open University is incorporated by Royal Charter (RC 000391), an > exempt charity in England & Wales and a charity registered in Scotland (SC > 038302). > > _______________________________________________ > Qgis-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/qgis-user > >
_______________________________________________ Qgis-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-user
