[OSM-talk] The Proposed Great Colour Shift

Minh Nguyen minh at nguyen.cincinnati.oh.us
Thu Aug 20 21:46:02 UTC 2015

Paul Johnson <baloo <at> ursamundi.org> writes:

> Along these lines, the standard style as it isn't too far off from what
Americans expect out of a motorist-oriented roadmap (though mapgeeks might
see it as a bit "German" by comparison to our maps).  Surface streets tend
to be all the same color (usually purple or red) with the thickness of the
lines tending to be rather thin, increasing in thickness up to primary or
sometimes trunk, with motorways tending to be purple with red borders.  Toll
roads are always green, there's never ways that are green that are not
toll.  This style of rendering is almost certainly heavily influenced by
Rand McNally, given it's ubiquity for casual use maps, which traditionally
has favored as described above in a somewhat simplified, stylized form (such
as rather than each ramp mapped out in detail, an entire, possibly almost
absurdly complex junction, is simplified to a single white square
representing a motorway junction).  Rand McNally was, for quite a long time,
the official cartography provider for the American Automobile Association,
which probably helped propel this style as an expectation.  Thomas Guide
(still usually preferred by professional local drivers even when equipped
with a GPS in the US, as a single metro gets published as a lay-flat atlas
hundreds or thousands of pages long with detailed annotation, sometimes down
to building suite level, at a scale roughly equal to z20 and handy for that
"last thousand feet" navigation) tends to use the same form, but rather than
simplifying junctions, often goes the map porn route by mapping out
everything to scale without simplification.

A few additional observations from having used a variety of print atlases by
Rand McNally, DeLorme, and municipal suppliers:

 - Controlled-access highways (that is, motorways with dual carriageways)
are commonly colored red, amber, purple, or blue. The specific color doesn't
matter so much, just as long as it isn't green (which is reserved for toll
roads, as Paul points out). Motorways are drawn as 2-3 parallel strokes,
imitating the dual carriageways.

 - Limited-access roads (think trunk or primary) are given a single thick
stroke, colored black, except for U.S. routes, which are usually red. All
other roads are given a single, thin stroke. In the West, prominent unpaved
roads might be dashed. There usually aren't any other classifications.

 - Streets in general are very thin because each street label is placed
above the street, not on it. However, I have a few municipal maps that do
place the label inside much wider roads, giving the map a more casual feel,
less like a schematic.

 - Full motorway junctions are simplified into white squares or diamonds,
while partial junctions are half that: a thin rectangle. At higher "zoom
levels", a complex junction such as a cloverleaf is drawn in full, but the
space inside it is filled in the same color as the motorway.

 - Shields are either reproduced in colors that match the signage, or
they're colored to match the road. So a map might end up with white-on-blue
Interstate shields, red-on-white U.S. route shields, and black-on-white
state route shields.

I would consider the proposed style to be closer to what a U.S. visitor
would expect than the current UK-influenced style.

minh at nguyen.cincinnati.oh.us

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