QspatiaLite Use Case: Connect Points with Same ID with Line Using the QspatiaLite Plugin

Another short example illustrating the effectiveness of geoprocessing with SpatiaLite, using the great QGIS-plugin QspatialLite.

We have a point-layer with an ID column ("Birds"), with each ID occuring twice, each ID representing an individual. The Ids should be used as start- & end-nodes for the connecting lines. Note that this also would apply if there were more than two points - then the same query could be used to connect all bird individual's points to a line by the order in each group!

We want each set of points, grouped by ID, to be connected. This is easily achieved by importing the points to a SpatiaLite-DB with the QspatiaLite plugin and running a very simple query:

SELECT 
    ID,
    makeline(Geometry) AS geom
FROM Birds
GROUP BY ID

Load the result to QGIS and that's it!