Thoughts on a map legend

[froggie]

For some of my GIS mapping projects, I'm working on a map legend to keep track of the various road types that I'm including in the projects.  Would like some input on a conceptualized legend that I'm considering.

This mapping style is a melding of several map types.  I've combined elements of the American Map series road atlases with elements of the Minnesota, Virginia, and Pennsylvania state highway maps, along with my own twists.

Here's the legend:



Thoughts/comments are appreciated.

[froggie]

A few additional notes:

While we don't have any 2-lane Interstates in this country (at least in the Lower-48 or Hawaii), I've included the 2-lane Interstate to reflect cases in other countries where segments of their national freeway network are 2 lanes instead of 4 lanes.

I'm using the standard engineering definitions of Freeway and Expressway here.  So Freeway is fully controlled access, while Expressway is limited access (i.e. private access prohibited, but allows at-grade intersections).

Super-2 can refer to either freeway or expressway.

Improved-2 is my own term, as discussed in a previous thread.  An Improved-2 highway has better geometrics than the typical 2-lane state highway, turn lanes at major and intermediate intersections, and paved shoulders, and may have some partial control of access (though private access may still be allowed).

Parkways, as I include them here, refer to limited- or controlled-access parkways.  Examples include the George Washington Parkway, the various New York state parkways (Taconic, Robert Moses, Palisades, Bear Mtn, etc etc), and the Natchez Trace.

Local Roads refers to locally/city/county-maintained streets and roads....i.e. roads not on the state highway system.

[usends]

In general, I like the color choices for the various categories.  One question, though: do you feel it's necessary to differentiate between "multi-lane interstate" and "multi-lane freeway"?  To me, they're pretty much the same thing, except for the shape of their markers.  However, if you do feel it's necessary, then you might consider using colors that are a bit more similar.  As it is, red and blue are on the opposite sides of the color wheel, so to me that implies that the road classifications are significantly different.

It's one thing to view the road classes in a legend, but it's another to see how the color and line-weight choices play out on an actual map.  So you might try them out on a test map and see how they work together.  But right now, just looking at the legend, I'm trying to determine which road class appears to be the most "heavy-duty" in the visual hierarchy.  In my opinion, it's the "multi-lane expressway".  I think this is because of the thick line-weight in combination with the dark casing and median.  On the other hand, the other multi-lane roads have no casing and a relatively thick white median, which I think tends to "soften" their appearance, moving them down in the visual hierarchy.  I assume this is not what you intended, so here's an idea:
- Switch the lines for M-L expressway and M-L freeway.
- Make M-L toll road the same as M-L freeway (black casing and median), except green.
- Make M-L interstate the same as M-L freeway, except blue.

Finally, these are cartographic issues that you're dealing with, so I'd like to invite you to another discussion group that I've found to be very helpful: it's called CartoTalk, and some of the best cartographers in the world post there.  http://www.cartotalk.com

[vdeane]

While we don't have any 2-lane Interstates in this country (at least in the Lower-48 or Hawaii), I've included the 2-lane Interstate to reflect cases in other countries where segments of their national freeway network are 2 lanes instead of 4 lanes.

I-81 over the Thousand Islands Bridge is two lanes.

I like the system you've developed.  Very comprehensive.

[corco]

I-81 over the Thousand Islands Bridge is two lanes.

As is I-93 through Franconia Notch

[mightyace]

One question, though: do you feel it's necessary to differentiate between "multi-lane interstate" and "multi-lane freeway"?

In general, call that one a personal preference.  Plus, for some of the projects I'm working on, it's important to note the difference.

However, if you do feel it's necessary, then you might consider using colors that are a bit more similar.  As it is, red and blue are on the opposite sides of the color wheel, so to me that implies that the road classifications are significantly different.

True, blue and red are opposites, but I'm also aping several other entities in this regard.  Numerous maps out there denote Interstates in blue and U.S. routes and/or major arterials in red.

The differentiation between Interstate and non-interstate freeway has been done on Official Pennsylvania roadmaps for years.  The current scheme is Blue for I-xx and Red for all other freeways.

In PA's case, it makes sense as the non-I freeways are more likely to be built lower than current interstate standards.

Once difference between froggie's legend and the PA map is that froggie uses two lines for the freeways and three lines for multi-lane expressway while the PA map uses the triple lines for the freeways and double lines for both divided hihgways and expressways.

[SSOWorld]

In PA's case, it makes sense as the non-I freeways are more likely to be built lower than current interstate standards.

Even interstates aren't up to standard (See I-70 in SW PA or the Turnpike) [/off topic]

A freeway is a freeway is a freeway.


except when it has at-grade intersections.

[Bickendan]

For some of my GIS mapping projects, I'm working on a map legend to keep track of the various road types that I'm including in the projects.  Would like some input on a conceptualized legend that I'm considering.

This mapping style is a melding of several map types.  I've combined elements of the American Map series road atlases with elements of the Minnesota, Virginia, and Pennsylvania state highway maps, along with my own twists.

Here's the legend:



Thoughts/comments are appreciated.

Strictly matter of opinion here: I do not care for the differentiation between an Interstate and a non-Interstate freeway. Generally, I find that the simpler the legend, the simpler the map, making it easier to read.
I also don't think that differentiating between multi-lane and two-lane is needed generally, but I've seen some of your Twin Cities maps on your site and do agree that in specific cases, which you use, it is needed.

Also, personal preference, I despise blue for freeways (and I despise Rand McNally's symbology; I much prefer the Thomas Bros' symbology). Consider an orange or a pink for your Interstates to avoid blue.

One quibble about the mult-lane local road: I think the line is too thick. Narrow it a little and it will still be effective, but less obtrusive.

Finally, if you're open to suggestions or redoing the scheme, I'll schill out my own legend 
(All cased lines are the same thickness as your '2 lane freeway', uncased are slightly thinner; the map I posted in Fictional doesn't use casing because of Illustrator's... quirks.)
Red, cased: Freeway
Red, uncased: Freeway ramp; express lanes
Magenta, cased: Multi-deck freeway
Magenta, uncased: Multi-deck freeway ramps
Green, cased: Surface highways
Green, uncased: Surface highway ramps
Purple, cased: Arteries
Purple, uncased: Arterial ramps
Black, uncased: Collectors
Grey, uncased (thin): Local
Orange, cased: Tunnels

[froggie]

I've come up with an "Option B", based on a few of the comments posted here.  Does this one look better?  Worse?  Other changes to make?

(sorry, Bick, I like blue for Interstates, so that one's gonna stay)

[vdeane]

I like it.

[route56]

I do think the black border for freeways looks better than the original... particularly since most map-makers (including state cartographers) use that system

[Bickendan]

(sorry, Bick, I like blue for Interstates, so that one's gonna stay)

Mmm. Still not sure about differentiating between Interstates and Freeways, as it implies that there is a difference in design of the roadway. To me, a freeway is a freeway, whether it has an Interstate designation or not. Also, using a differentiation may also require a 'Toll Interstate' category.

So if blue is going to be used for Interstates, I suggest it be used for freeways as well.

[froggie]

Still not sure about differentiating between Interstates and Freeways, as it implies that there is a difference in design of the roadway.

Quite often, there is.

Two other reasons why I keep the differentiation.  For a couple of my GIS projects, I need to differentiate between the two.  And in a more general sense, this scale could be applied to other countries, where there ARE differences between their national-network freeways and lesser-routes that may also be considered freeway.

[mightyace]

I like it better than option A.

The blue/green/red is intuitive, at least to me, since it matches the current PA official state map.

My only question is why is there a separate designation for parkways.  Is that because many parkways don't allow trucks?

[treichard]

The Interstate vs. non-Interstate freeway distinction is helpful in cluttered map areas to help distinguish the freeways where there's no room  for enough route numbers to do the job.

Similarly, distinguishing state-numbered and local highways of the same quality (e.g., two-lane back roads) is helpful.  Take a look at the PennDOT official transportation map, where lesser state-numbered highways are shown in thick black and the more significant local highways in thin black.  Then compare to a recent Rand McNally USA atlas where both types are shown in the same color, thickness, and style.  The PennDOT style distinction more easily answers the question "where does route # go between marked numbers?", while the same-style way leaves you guessing.

So it can be quite helpful to a map reader to clearly distinguish between designation types as well as highway types without cluttering the map with too many extra numbers.

[Scott5114]

Similarly, distinguishing state-numbered and local highways of the same quality (e.g., two-lane back roads) is helpful.  Take a look at the PennDOT official transportation map, where lesser state-numbered highways are shown in thick black and the more significant local highways in thin black.  Then compare to a recent Rand McNally USA atlas where both types are shown in the same color, thickness, and style.  The PennDOT style distinction more easily answers the question "where does route # go between marked numbers?", while the same-style way leaves you guessing.

God, that's the worst thing about McNally, IMO. Especially bad when a route ends at a cross-highway and a major non-route road continues beyond that...

Blue/green/red works quite well, IMO. On Wikipedia, we use blue for all freeways and green for toll roads. Both ODOT and KDOT use green for freeways, yellow for toll roads, and red for other freeways, however.

[froggie]

My only question is why is there a separate designation for parkways.  Is that because many parkways don't allow trucks?

Correct.  Real-world, it applies mainly in NY, CT, and the DC area, but I need it for some of my projects...

[Bickendan]

RMN's symbology is just... problematic in general. A single color for freeways works best on the Street Guide or Regional Atlases, not the national atlas where an entire state must be compressed to a single page.

And don't get me started on RMN's Street Guide symbology.

Froggie, one last thing to consider with yours is what you're trying to most emphasize. RMN loves using reds for their arteries (red cased in red), which makes them the dominant feature -- over freeways and highways, helping give the map an incredibly cluttered look.

Legend B's most noticeable feature will be the Improved-2's, followed by the Super 2's and non-Interstate freeways. My sense is that there will be a good handful of Improved-2's running loose in the wild, less so than Super-2's, and when present, they will draw the eye. This is great if this is your intent; if not...
Conversely, the blues fade in and present an illusion of being part of the physical geography (water bodies). Obviously, the Interstates aren't, and they're easy enough to pick out, but against a spate of red freeways (Los Angeles, Seattle would be good examples), it may not work as well.