[Talk-ca] [Imports] Proposed import: Surrey, BC waterways

[Richard Weait]

On Tue, Mar 29, 2011 at 2:31 AM, Paul Norman <penorman at mac.com> wrote:
> In short, the waterways in Surrey BC are largely from NHN data which in some
> cases is accurate, but tends to be 20-30 years old. I'm proposing importing
> data from the city, licensed under PDDL. I'm at least 2-3 weeks away from
> being ready to do the import as I have some other priorities currently but I
> wanted to get feedback.
>
> I see this import as fixing two problems. The first is the old NHN data. The
> second is the high number of unmapped ditches in Surrey. Because of the
> nature of the soil, it is very common for houses to have drainage ditches in
> front of them. These are largely unmapped, but the shapefiles appear to have
> all ditches.
>
> Legal: The data is licensed under PDDL, a compatible license.
> Accuracy: The positioning is very good.
> Completeness: Not all culverts are mapped. Random checks revealed no missing
> ditches or streams.
> Existing data: It was all mapped by me or imported. I am proposing removing
> it.
>
> There are more details at
> http://wiki.openstreetmap.org/wiki/Canada:British_Columbia:Vancouver/Imports
> /Surrey/Waterways about the exact tagging. I intend to refine this, but this
> may require a couple of site surveys. Before importing I will post a sample
> .osm file for review.

I think that the Surrey, BC data under PDDL is wonderful.  And I know
that you have previously looked at their address data and road data
and found it very helpful with addr:, maxspeed and hgv information.

I wonder if these common roadside ditches will share the same
drawbacks as sidewalks in some other areas.  In fact, if sidewalks
exist in this area as well, the ditches may compound the problems of
sidewalks.  In summary portions of the OSM community are divided about
sidewalks.  Some feel that mapping sidewalks isn't needed where they
are common.  If all roads have sidewalks, why map them separately?
Others feel that sidewalks should be indicated as tags on roads, like
sidewalk=both for both sides.  Others feel that mapping each sidewalk
with a separate highway=footway way adds important detail to the map
for pedestrians.  Still others find that editing an area with a
substantial number of separate sidewalk ways makes editing more
difficult;  smaller download areas are permitted, editing the shape of
a road means editing the shape of two sidewalks as well, adding other
objects like building and POI have additional ways to "snap to"
unintentionally.

A road with two  sidewalks and two ditches sounds like a further
complication.  There would then be five ways for each road?  Perhaps
mapping each ditch, where they are common is over the line towards
photo-realism or "micro-mapping" in my book.

Would these ditches then need additional tunnel / culvert splits at
each intersection?