This blog entry from Simon Mercier describes how this works.
http://www.mapgears.com/en/blog/archive/2013-03-05-roads_network_mapping Lars S. -----Originalmeddelande----- > Från: "Stephen Woodbridge" <[email protected]> > Till: [email protected] > Datum: 2017-01-22 05:35 > Ämne: Re: [mapserver-users] Mapfile CLASS hierarchy > > Oh, and I forgot to mention that if you want objects rendered in a > particular order, then your should sort the data in the sources in that > order. You can do this with order by clause on SQL based data sources > and using shpsort for shapefiles, ogr2ogr and also sort data. > > On 1/21/2017 10:03 PM, Stephen Woodbridge wrote: > > Within a layer objects are always drawn in the order they are delivered > > from the datasource. Think of the CLASSes are an IF-ELSEIF-BLOCK, when > > an object is presented each CLASS is tested and the first one the > > accepts the object renders it. > > > > I often up a default class at then end that has no expression ans render > > it in red just so I can see if I missed any cases, but remove it when > > I'm done developing the mapfile. > > > > -Steve W > > > > On 1/21/2017 8:48 PM, Stefanos Anastasiou wrote: > >> Hi list, > >> according to the documentation, the first layer in the mapfile is > >> drawn first, and the second is drawn on top of that and so on... I was > >> wondering if the same principle applies to the CLASS object as well. For > >> example: I have a "Roads" layer stored in PostGIS with a "Category" > >> column representing the different types of roads. So a category 3 is > >> very small roads, category 2 is city roads, 1 is major roads and 0 is > >> highways and on the same layers I create four CLASS objects with > >> different styles for each Road category. But regardless the order of the > >> classes (either I draw the small roads first or the highways) the same > >> effect insists: the small roads are drawn over the highways. So what > >> is the solution here? Create different layers of the same dataset > >> representing the various values of the "Category" column ?? > >> > >> > >> Regards, > >> -Stefanos > >> > >> > >> _______________________________________________ > >> mapserver-users mailing list > >> [email protected] > >> https://lists.osgeo.org/mailman/listinfo/mapserver-users > >> > > > > > > --- > > This email has been checked for viruses by Avast antivirus software. > > https://www.avast.com/antivirus > > > > _______________________________________________ > > mapserver-users mailing list > > [email protected] > > https://lists.osgeo.org/mailman/listinfo/mapserver-users > > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > > _______________________________________________ > mapserver-users mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/mapserver-users --
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