With many thanks to Richard McDonnell, his suggestion of using rules instead of categories solved the problem I had. The result is http://mrdata.usgs.gov/geology/state/lithclass.qml with context provided by http://mrdata.usgs.gov/geology/state/
I'm still a little puzzled by what's required and what is not required in the QML file; I'm guessing that the solution would be to delve into the QGIS source code, but it would be nice to have at least a rudimentary document; I simply used the automatically-generated qml as an example, then omitted a lot of things, but was pleased at how simple I could make it and have it still work. Thanks! Peter On Thu, Oct 15, 2015 at 6:46 AM, Richard McDonnell <richard.mcdonn...@opw.ie> wrote: > Peter > > I would advise you to use the QGIS rule based symbology to do what you > require, the filter would be something like:- > > your attribute_column _name = 'carbonate rock' OR area_code = 'carbonate' > > keeping it simple!! > > This should do the trick for you. > Regards, > > Richard. > > > On 14/10/2015 17:20, Schweitzer, Peter wrote: > > Is there a QML reference document? > > What I really want to do is specify that two different category values > will have the same symbol, like this: > <category render="true" symbol="64" value="carbonate rock" > label="Carbonate rock"/> > <category render="true" symbol="64" value="carbonate" label="Carbonate > rock"/> > I want to read this as > > when the value of the attribute is EITHER "carbonate rock" OR > "carbonate", render the feature using the symbol named "64" > > But this does not have the effect that I want, so I'm thinking > incorrectly about how the QML file works. > > I would welcome advice on how to do what I want, or direction to the > QML reference, or both. > > Thanks! > > Peter > > > OPW - Ag féachaint don am atá le teacht - Ag caomhnú ón am atá thart > OPW - Looking to the future - Caring for the past > > Email Disclaimer: http://www.opw.ie/en/disclaimer/ > > _______________________________________________ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/qgis-user -- Peter N. Schweitzer (U.S. Geological Survey, Reston, VA 20192) (703) 648-6533 email: pschweit...@usgs.gov http://geology.usgs.gov/peter/ _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user