Document the centreline data

[Nate-Wessel]

What this pull request accomplishes:

• documents the centreline data

Issue(s) this solves:

closes #801

What, in particular, needs to reviewed:

• facts, clarity

What needs to be done by a sysadmin after this PR is merged

NA

[Nate-Wessel]

Nudge @radumas

[Nate-Wessel]

@chmnata This is not meant to be complete; I've only been able to find out so much about this dataset, and currently there is no documentation that I'm aware of. This is just intended to be a start that we can add to later as time permits. Thanks!

[chmnata]

Thanks for starting a readme for centreline! Some comments below, and I will have to update it after merging to include some new changes on centreline_latest.

[chmnata]

FYI @raha1986 looked into intersection before #466. We could also include some comments mentioned on centreline intersections e.g. elevation10 can be used to filter major and minor arterials, and limitations like how centreline id for intersections are not unique

[Nate-Wessel]

I'm not sure I'll be able to give a good summary of the discussion there. Perhaps we could let Raha add to this documentation in a later PR?

[chmnata]

Thanks @Nate-Wessel for the speedy fixes, @radumas wanna take a quick look at it? FYI I am gonna add the routing stuff in after this merge.

[radumas]

I realize there's a centreline folder but I kiiiind of find it not that useful (anymore) (this is about to be superseded by #885 ). Feel like this should instead be front and centre in the gis/README.md, though maybe it's a bit long. IDK.

There should be a reference somewhere that the code for the pipelines for these datasets are in gccview/ folder.

centreline_intersection_point I would say is the preferred intersection layer, it is almost unique on intersection_id

intersection appears to be 1 row to describe every relationship between edges at a node.

I think it would be helpful to add that intersection_id is the ID in the intersection layer(s) that matches centreline_id from MOVE

[gabrielwol]

I appreciate this attempt to document the centreline.
As a centreline user recently what I feel is still lacking is some obvious pointers to use gis_core over gis, and centreline_latest over centreline.

• As part of this PR could we add comments to these two schemas and most of the tables under gis_core?
• Add a link and overview of this readme under the main gis/readme.md.

[gabrielwol]

Great improvements to the documentation. Also thanks for adding comments on those tables in bigdata.

[gabrielwol]

@radumas I addressed your comments from above. Can you review updates?

[chmnata]

Thanks for adding all the other folders description and more info on intersection! @gabrielwol

[radumas]

Great job team