2

i am working with temporal controller for just a cluple of days - before i've been using time manager. right now i am searching for a way to display the last/latest/most recent feature within a time interval which is defined by the "Frame" settings of the "Temporal Controller" GUI.

finally it should look like img_01 (see below): the yellow trace is implemented already and works fine. but the red dot is the thing i am asking for ...

within my time frame of 15min the temporal manager returns a set of 3 (sometimes 4) points. and i would like to implement kind of a selection algorithm that returns just this one point, which is the last one within the frame i.e. the one with the MIN value of an expression that could look like @map_end_time - "points_time"

i have been trying differnet things but

  • i could not find out how to get a collection/set of geometries within an QGIS expression by using "geometry generator"
  • and even if i could find out how to get that collection i would not be able to select the one last point with the max-value of the time-field
  • i've tried to use the temporal controller variables @map_start_time and @map_end_time in QGIS Query Builder to select features on the layer level - but i could not find a way to get along with the syntax for handling date and time SELECTs on geopackage-data within the Query Builder-environment
    e.g. how a select of to_datetime(@map_start_time + '2 Hour') could be translated into QGIS Query Builder syntax ? (the expamle works fine in QGIS expressions -> see labels/last line out of 4 in img_02)

img_01: enter image description here

img_02:

img_01

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.