Routes and networks

Two ways of drawing lines from rows that are points: a route joins one query's rows in the order they come, and a network joins the nodes of one query by the edges of another.

Routes

Map → Draw as a route and pick the queries. Each row is joined to the next, in the order the query returns them, so order the query by time:

SELECT time, lat, lon, speed FROM gps WHERE vehicle = 'T1' ORDER BY time;

The query keeps its own dataset and layers. Beside it the panel adds a dataset of segments, "Query A · route", one row per pair of consecutive rows: the starting row's columns, plus both ends as lat0, lng0, lat1, lng1. A Line layer draws them.

Query A (points)	Query A · route (segments)
row 1 -2.890, -79.00 20	1 → 2, with row 1's speed 20
row 2 -2.889, -78.99 35	2 → 3, with row 2's speed 35
row 3 -2.887, -78.98 70	3 → 4, with row 3's speed 70
row 4 -2.884, -78.98 55

Because each segment carries its starting row, the line can be coloured and sized by any column, and the Line layer's target arrow shows the direction of travel.

A row with no position breaks the route at that point: the segments into and out of it are left out.

On a map with a saved configuration

The Line layer is added by itself only while the map has no saved configuration, like every layer the panel builds for you. Once it has one, add a Line layer on the route dataset in the side panel, its columns lat0/lng0 → lat1/lng1, and save the map.

When not to use it

A route is one line through every row. Rows of several vehicles in one query make one line jumping between them: for those, a trip id makes trajectories, one animated path per vehicle.

Networks

A query of edges is drawn as lines between the nodes of another query. This is the shape of Grafana's Node graph panel, and nothing has to be configured:

• the edges are the frame named edges, or the one with source and target columns, and no coordinates of its own;
• the nodes are another query with an id column and coordinates.

-- A: nodes
SELECT code AS id, name, lat, lon FROM stations;
-- B: edges
SELECT source, target, trips FROM links;

Each edge takes the positions of its two nodes and keeps its own columns, so a Line layer can colour and size it by trips. An edge whose source or target is not among the nodes is left out. The nodes are an ordinary point dataset.