To North Arrow or Not to North Arrow
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I started my GIS education back when hand cartography was still a course offered at UCLA. My early teachers drilled into me the standard of adding a title, north arrow, and scale bar automatically to all maps. The GIS manager at a place where I first worked was adamant that all maps produced in that GIS group have north arrows placed onto them. A recent post on another blog to a quick article I had written about things to consider when making a map brought up the issue that not all maps should or need a scale bar or north arrow. Using north arrows and scale bars has admittedly become rote over the years for me and I felt it was time to take a look at this issue.
Some advocate the use of the north arrow in almost every instance, with few exceptions. Jon Zeitler, Science and Operations Officer at the National Weather Service Forecast Office in Austin, Texas responded to an email debate about the use of north arrows with:
The addition of a north arrow can never harm a figure, only help with clarity. I’m flexible enough that if it’s presented on the first of similar figures, it can be left off subsequent frames. Also, some figures (e.g., a U.S. map with number of tornadoes per state) don’t need a north arrow. So, while certainly not as “required” as a distance scale, best practice would be to include a north arrow or compass rose.
The use of north arrows does require some critical thinking. As in this post on Esri’s Mapping Center entitled “Does every map need a north arrow or scale bar?” blog:
I teach my students that a north arrow and scale bar are not necessary on all maps — indeed some should not have them, such as orthographic views of the world. One common mistake I see is a north arrow on a smaller scale map (say the United States) in a Lambert Conformal Conic or Albers Equal Area projection — on these types of map, north is only North along the central meridian (due to the convergence of the meridians toward the pole). But we still have an obligation to help the map reader with scale and orientation, so instead of a north arrow the graticule should be shown. A cardinal rule is that a large scale map oriented such that North is not “up” must have an orientation indicator, most easily shown with a north arrow, since these tend to be larger scale maps.
The City of Santa Monica’s use of orientation on its maps is a great example of needing a north arrow. For aesthetic purposes, the City’s GIS shifts the display of the city so that north is offset (see below). Per Mike Carson, the GIO for the City of Santa Monica, the maps are rotated 46 degrees so that the beach is located at the bottom of the map and most of the streets run vertical/horizontal. The new orientation allows the boundaries of the city to fit better within rectangular sheets of paper.
A map of the city, with north towards the top of the page, looks like this map produced by the Big Blue Bus Company:
Santa Monica Big Blue Bus Lines (click on map for source file).
The City of Santa Monica’s GIS reorients the map so a similar map showing the bus routes within the city looks like this:
Bus Routes within the City of Santa Monica (click on image for source file).
When considering the issue of whether or not to use north arrows, it’s good to understand the answers to a few questions about the map before deciding the appropriateness of using a north arrow:
- Is the map showing a large area such as a map or the world, or the United States where north orientation would be obvious to most of the general public?
- Is north towards the top of the map?
- If not, is it clear which direction is north without needing to add a north arrow?
- Does the intended audience of the map understand the orientation of the geographic area shown? As Jerry Ratcliffe from the Department of Criminal Justice notes (tongue in cheek) “Anyway, if you have visitors from outside your suburb, city, or country, why the hell should they want to know which direction is North, so they can orientate themselves? They probably are not interested anyway.“
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Tags: cartographic elements, cartographic philosophy, Cartography, map elements, map making, orientation, use of north arrows
I can’t believe this is even a question… North arrows and scale bars are two of the most important items on a map. It boils down to legalities. Nobody likes to be sued because someone didn’t know which way was north or that a map wasn’t to scale. What about map reproduction? What if it gets rotated unknowingly? If you plot of six paper sheets of maps and only the top sheet has a north arrow, what happens when you lose the top sheet?
At least take some pride in your work. It boils down to tradition if you want nothing else. A good looking map can look great with a well designed North Arrow!
So that nobody blows a gasket the best rule to follow is that the situation dictates the use of a North Arrow. As was stated previously, most people that would be looking at a map of the world or their continent/country know which way it has been oriented. Governments, as a rule, don’t orient their country to the South; thus not necessary, again, DEPENDING ON IT’S PURPOSE.
Cartographically speaking they can help visually and even be used as a signature of sorts so that your hard work can be recognized and take pride in your work.
Either way, pride will be taken where it is due. The times and traditions change learn to change with them or cease to learn. After all you perform your craft on a computer instead of squiggling lines with ink stained fingers on a piece of reed parchment. Do you not?
North arrows are not necessary on certain coarse scale maps not just because of the instant recognition of north (in the case of a map of America) but also because they may not be appropriate at that scale depending upon projection. When a conic projection is used, maps of large portions of the earth are better off using lat/long lines because the true direction of north changes across the map. This of course is an exception as most maps are set at a much finer scale.
Are you aware of another recent post on this same topic? http://cartastrophe.wordpress.com/2011/09/13/assembly-line-map-elements/
Yes. As noted, this article was written as a result of that blog’s reaction to a previous post on this site. The post on the Cartastrophe blog was addressed in Ten Things to Consider When Making a Map.
Hey folks,
It all sounds like good ol’ common sense to me. I get really frustrated when I pick up a map from the hotel lobby and it doesn’t have a scale or north arrow. Other times when you see something on the news, weather- or crime-related, questions or conclusions may arise that specifically pertain to these elements. So please include them!!
Of course, you don’t need it on maps of your state or country. As mentioned earlier, when the scale is that large, different projections are used that eliminate the need for either.
More important for me is an arrow showing southern aspects. Not because I live in the southern hemisphere, but it shows the way the light goes from west to east on a plot. So to me North arrow isn’t always necessary as long as the User can visualise the West/East orientation.
By the way, I think the last map makes more sense…