[OSM-talk] Mapping streets as areas - can I do it now?

Richard Weait richard at weait.com
Tue Feb 23 04:10:10 GMT 2010


I was initially impressed with the German example of area mapping but
I have had a change of heart.  While an interesting experiment, and
relatively well implemented in the small test area, I just don't think
area mapping of ordinary roads makes sense.

To do area mapping without also doing the traditional OSM vector
mapping of those roads just seems like low-grade vandalism to me.  Why
would a mapper choose to say, "I'm going to make a really detailed
representation of road width and corner radii, that looks great on one
renderer at one zoom level, and I just don't care that it breaks
routing, breaks street names, and takes my time away from mapping
other roads, or addresses, or crosswalks."  I don't get it.  It seems
a very limited view of the map for one specific, perhaps selfish
implementation.

I expect to find wide variation in what individual mappers find worthy
of their mapping time.  When you consider that we have a map that we
can improve with roads, intersection, interchanges, rivers and other
waterways, cycle and multi-use paths, snowmobile trails, kayak routes,
canoe portages, trees, steps, power pylons and lines, turn
restrictions, businesses, buildings, zoos with penguin enclosures,
street lighting, fire hydrants, and so many other things *deep
breath*.  Some will map half of these things, and many will map a much
smaller subset.

I understand why some mappers do cycle trails and others do coffee
shops and bowling alleys.  How much does the width of one road, plus
the radius of the curb at the junction really add to the map?  And
this is all while ignoring so many other features.  And as far as I
can tell, these appeals to show reality more accurately extend only as
far as the paved driving surface.  Even the curbs are ignored.  No
curb:height or curb:width?  Not even any indication of curb ramps,
crosswalks, or audible crossing assistance?  The focus is just on this
idea that the curb has a radius.

Students at the University of Maryland have even built a pedestrian
routing system that allows choosing sloped curbs, and avoids steep
inclines.
http://seamster.cs.umd.edu:8090/map/index.html#
Check the data, they don't bother with area-mapped roads.
http://www.openstreetmap.org/?lat=38.987313&lon=-76.941263&zoom=18&layers=B000FTTT

Having said all of this, and this email is too long to read, corners
with curb radii can look nice.  Why not put energy into allowing a
renderer to draw the radius for you?  Surely this can be abstracted in
a way that creates a sensible corner for a large class of general
intersections?  Why tag and draw every blade of grass, when we can
create a polygon of natural=grass?




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