Is there a way to make a QGIS symbology that uses attribute fields from other features?
<featurecollection> <feature> <id>1235</id> <!-- same id --> <time>100</time> <!-- older ----> </feature> <feature> <id>1235</id> <!-- same id --> <time>101</time> <!-- newer ----> </feature> <feature> <id>1236</id> <!-- unique id -> <time>102</time> <!-- is new ----> </feature> </featurecollection>
When there are 2 features with the same "id", then the symbology of the feature having the older time should have a certain (symbology A) style. The feature with the identical "id" with a newer time value should have another (symbology B) style.
When there is only 1 feature with an "id", then that feature should have the "B" symbology style.
With symbology categorize this will of course not work. A have some basic knowledge of Rule based symbology .. is that the way to go?
Or are there other ways?
Adding a new field to the source file is not possible. An XSD determines the fields and I cannot add a field to that XSD like that.
Possibility 2: can I add a attribute field and have it populated dynamically within QGIS?