withPoints X

[cvvergara]

pgr_withPointsDD(Edges SQL, Points SQL, root vid, distance, [options A])
options A: [directed, driving_side, details]

become

pgr_withPointsDD([Edges SQL, Points SQL, root vid, distance, driving side, [options A])
options A: [directed,  details]

"Both" is only valid on undirected graphs

[krashish8]

What if the graph is undirected and the end pgRouting user gave 'b' driving_side? Shall we raise an SQL error in that case?

Also, what will shall be the default value of driving side - same as before ('b') or are we changing it to 'r' for 3.6 onwards?

[squarege]

Confusion:

In the change @cvvergara do here, in fact, [r,l,b] all treated as b on undirected graphs, and b is still valid on directed graphs. It's different from what we discussed before in which "Both" is only valid on undirected graphs.

Should I throw an error when b is given on directed graphs?

[cvvergara]

Lets read a little:
https://docs.pgrouting.org/latest/en/withPoints-family.html#driving-side

[squarege]

Summary of the discussion in Gitter

When thinking of vehicles:

• There are countries with left side driving, like India, UK
• There are countries with right side driving, like Mexico, China
• No country has both sides driving
• Directed graph is used to represent streets for vehicles

When thinking of pedestrians:

• They can go in both directions in any case.
• driving side is meaningless for pedestrians.
• Undirected graph used to represent sidewalks.

Q: What would be the best default value of "driving side" for vehicles
A: r as default for vehicles, reasons:

• Most of app are for vehicles, and can only choose between r & l.
• Most of countries are right side driving.
• So r is more suitable for most cases.

[cvvergara]

So vehicles is 'R', 'L', 'r', 'l'
Therefore directed graphs is 'R', 'L', 'r', 'l'
But, who knows... for "routing" application that is what makes sense
but pgRouting is about graphs
and maybe, it is been used to throw cables for electircity and many unknown application that we as developers of the back end can not think.
So, for the moment, lets keep directed graphs valid values to be: 'R', 'L', 'r', 'l'
we will need to think what 'both' really would mean in a directed graph
For pedestrians
aka is undirected graph
is Right and left driving side would be walking side, does not matter
so 'Both' is when it makes sense
Because it is no loger default:
pseudocode

if graph is directed then valid values are  'R', 'L', 'r', 'l', 
else valid values 'B', 'b'

There is no default value, so do not change the value given by the user
of course this applies to the C function you are creating
Do not change the old logic on the old function, aka the one that is going to be deleted on v4
Later on we will see if 'B' and 'b' is also ok on directed graph, and what that value be interpreted as.
Or if 'R', 'L', 'r', 'l', be added to undirected graph.
but for the moment keep the

if graph is directed then valid values are  'R', 'L', 'r', 'l', 
else valid values 'B', 'b'