To north arrow or not to north arrow?
I started my GIS education back when hand cartography was still a course offered at UCLA. My geography teachers drilled into me a 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.
Using north arrows and scale bars inside the map frame admittedly became rote over the years for me until I took a look at the debate about whether or not a map actually needs a north arrow. Believe it or not, cartographers can become quite passionate over the issue.
The Debate About Using North Arrows on a Map
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:
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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. This post by Aileen Buckley on Esri’s ArcGIS blog entitled “Does every map need a north arrow or scale bar?” provides some food for thought on the issue:
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 map 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.
An Example of When to Use a North Arrow on a Map
The City of Santa Monica’s use of map orientation is a great example of the need for a north arrow. For aesthetic purposes, the City’s GIS shifts the display of the city on its maps so that north is offset.
The reason why Santa Monica GIS rotates its maps 46 degrees is so that the beach is located at the bottom of the map and and the grid layout of the streets are now vertical and horizontal with the edges of the page.
The new orientation allows the boundaries of the city to fit better within rectangular sheets of paper. All maps shift the orientation of the north arrow to match the rotation.
A map of the city produced by Santa Monica’s Big Blue Bus Company (the location public bus transportation system) has a layout with north towards the top of the page:
The City of Santa Monica’s GIS reorients the north so a similar map showing the bus routes within the city looks like this:
What to Consider When Using a North Arrow on a Map
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?
- Does your map have a reference map or inset map that lets the reader understand already where north is located?
- Is the north direction towards the top of the map?
- If not, is it clear what the direction of north is without needing to add a north arrow?
- Would adding a north arrow help with understanding the context of the area you are showing in your map?
- 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.“
- Will your audience need to compare maps of the same geographic area that have different map orientations? In the case of the Santa Monica bus maps that I discussed earlier in the article, having a north arrow on both maps would help the reader. If a person takes a Big Blue Bus map with its north orientation and then tries to compare routes on a north rotated map produced by the City of Santa Monica, having a north arrow on both maps would be important for context.
The decision to include a north arrow on a map should be based on the map’s purpose, the intended audience, and the degree to which orientation is important for understanding the map’s content.
This article was originally written September 13, 2011 and has since been updated.
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…
Maps by convention are north facing. Only put a north arrow if the map has no graticule lines and is rotated relative to north.