5:21 p.m.
Topic 1:
I had seen some interesting behavior where the name of an abandoned
line was rendered even though it was not tagged in the way but was
tagged in a relation. I also saw cases where a street was rendered
with an abandoned line even though it wasn't tagged on the way but was
included in the relation. I've also seen instances in the
electrification layer where there's a double render: both the
electrification color and a gray line appeared in the same location
conflicting. Thirdly I've seen instances where the way and the
relation were tagged 'abandoned' and the line showed up as solid
rather than dashed.
It took me a while to figure out what was going on since I had seen
ORM documentation that says we do not render relations. It turns out
that the OSM backend turns relations into ways, assigning them a
negative osm_id. ORM then renders these ways.
Basically, if a relation is tagged
railway=construction/abandoned/razed/disused/rail/light_rail/tram/subway,
it will render in ORM. There are guidelines that say don't use
railway=rail on a relation
(https://wiki.openstreetmap.org/wiki/Tag:route%3Drailway). Perhaps
they should be expanded. Maybe even a validation rule should be added
to the editors.
So the question I have is what's the best way to deal with these
relations? For some the easiest thing to do is remove the railway tag
from the relation. For others, the relation is so large (I saw one
last night that was 500+ ways), and not every way is individually
tagged that map accuracy would be decreased if the railway tag was
removed from the relation. For those cases, it seems easier to de-tag
a few ways and let the relation take over. But then if the way ends
up being blank, I feel guilty and I then rely on others to not delete
it and realize it's part of a relation. I also feel like I'm
violating the rule of not tagging just for the sake of the renderer.
Thoughts? Are there any guidelines?
Topic 2:
The ORM renderer will shade in turntables and traversers if and only
if they are polygons. Took me a while to figure out why some were
rendering (like
https://openrailwaymap.org/?style=standard&lat=40.87473288924837&...)
and others weren't. It seems that a "closed way" (group of nodes
joined by a line where the starting node is the ending node) isn't
automatically a polygon unless certain tags are present. I'm thinking
in the above case the tourism=attraction tag may have tripped the
above case into a polygon. An area=yes tag will always force the
database to create a polygon.
So the question is what do we do with all these turntables and
traversers that are closed ways and not polygons?
-retag with area=yes to force the renderer? I've done this for
several but I'm not sure it's the right thing to do
-request the OSM Project make a change so that a closed way tagged
'railway'='turntable' is treated as an area when uploaded. Not sure if
this is a backend or editor issue. Is this even a backend thing or is
it a local database thing?
-have ORM render closed ways and areas/polygons. Not sure that's even
possible with the rendered.
Thanks for reading,
Jonathan