Is there a way to make a QGIS symbology that uses attribute fields from other features?
Example:
<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?
Other possibilities?