ST_MakeLine returns Unsupported geometries not rendered in geometry viewer

Question

I am trying to run a ST_MakeLine query that will return the shortest distance between given coordinates The code is as follows:

SELECT ST_MakeLine(route.geom)  as test
FROM (SELECT *
      FROM pgr_fromAtoB('roads2_noded',73.1789,33.5183,73.1768,33.5191)
      ORDER BY seq
     ) As route

The result looks like this:

it's clear that the result does not show null. But when I view it in the Geometry Viewer, it gives the following message:

Can someone tell me what this message means and how can I find a workaround to this problem? The geometry type of my roads shapefile is MULTILINESTRING.

St_AsText (route.geom) shows the following result:

SELECT ST_AsText( ST_MakeLine(route.geom)) FROM (SELECT *FROM pgr_fromAtoB('roads2_noded',73.1789,33.5183,73.1768,33.5191)
      ORDER BY seq
     ) As route

Using simple Select from pgr_fromAtoB gives:

SELECT * FROM pgr_fromAtoB('roads2_noded',73.1789,33.5183,73.1768,33.5191) ORDER BY seq

The roads2_noded is the roads shapefile I am working on shown below:

Answer 1

pg_Routing functions cannot be used for MultiLineStrings. Therefore, first create a new table with all the data entries of the roads2 table. Then add the columns of roads2 to the new table. For example id, sub_id, name, distance ,geom etc. Then use the following query to convert the MultiLineString geometry of roads2 to LineString.

ALTER TABLE my_table
ALTER COLUMN geom TYPE geometry(linestring,4326) USING ST_GeometryN(geom, 1);

After that add the geom column of roads2 to the new table. After that apply the road network and topology queries i.e. pgr_nodeNetwork and pgr_createTopology and create the function pgr_fromAtoB Then run the ST_MakeLine query:

SELECT ST_MakeLine(route.geom)  as test
FROM (SELECT *
      FROM pgr_fromAtoB('my_table_noded',73.1789,33.5183,73.1768,33.5191)
      ORDER BY seq
     ) As route

The result will show the geometry: