Cartographer's Toolkit

Map Making Tips, Tricks, and Inspiration

Map Take-Aways

April 20th, 2017

One key to cartographic success is employing a deft mixture of subtle and forthright elements in order to achieve that most difficult of harmonizations: effortless yet highly informative communication. Here’s an example that came up in my twitter thread just a few moments ago:

Here we see several elements that help to achieve the right balance:

  • Masked basemap: focuses reader attention on the area of interest while also providing geographic context.
  • Gray titling: “DISTRICT OF COLUMBIA” is in a light gray color, which minimizes its appearance despite its being diffused across the legend box. You see this often with titles in all-caps.
  • Black titling: “LAND USE PLAN” is what the map author really wants you to read first, so this is both in black and all-caps.
  • Legend box in light gray: since the light-gray text elements could blend with the light-gray masked basemap, the legend box is needed in this case, but it is kept subtle.
  • Bold colors for the landuses: landuse plan maps are notorious for their cartographic difficulty in that the combination of landuses and basemap information can make for an entirely cluttered aesthetic. Making the landuses the number one focus point was a good idea for this map.
  • Polygon boundary colors in slightly darker shades: slightly darker polygon boundaries in the same hue as the polygons helps to define the boundaries of the polygons while not overwhelming the map. Black boundaries on all polygons would not have served well here.

A New Kind of Directional Icon

March 26th, 2017

Maps that use projections in which North is only constant along meridians are disingenuous when it comes to their north arrows and scale bars, since both scale and North vary depending on where they are on the map. On large scale maps this matters very little. On medium and small scale maps, however, this matters a lot. The typical solution for the directional indicator is to display graticule lines instead of a north arrow. There are some potential solutions for scale bars, too, but I will focus only on the directional indicators in this post.

The problem with using graticules is that they can clutter up the map unnecessarily. You can seek to minimize that clutter by using thin gray line symbology. In this example, you see how a thin gray graticule looks. Also notice that the north arrow that I’ve placed here solely for purposes of illustration is definitely erroneous for most parts of this map.

Graticules and north arrow

You can go a step further and run the graticule lines only over the portions of the map that aren’t as important: the oceans, for example. That isn’t always possible, especially for those of us who make extensive use of single-layer basemaps such as that shown above, where there is no way to place the graticule layer between the oceans and the land. In this particular example it wouldn’t much help to run the graticules solely over the ocean area anyway, since there is too little ocean area compared to the land area and therefore only a single meridian line would be visible.

In no way is a graticule grid covering this entire map a bad thing. But what if there might be another option to consider on maps that have a lot more information?

What if we made an icon out of the graticule grid to illustrate the directions, placed in a corner of the map just as we would have done with a north arrow if it had been an equirectangular projection? An illustration of this is probably the best way to explain it:

Map with graticule icon

Zooming in to the lower-right corner of the map:

Graticule icon zoomed in

To create this–and here I’m using ArcMap but it should be a very similar process in your GIS of choice–I created a new polygon data layer and edited it such that it contained one polygon of the extent of the map. This was pasted into a new data frame and that new data frame was set to the same projection as the first, then this data frame was zoomed to the extent of the new polygon layer. Now they both show the same exact location.

The new data frame needs to have the same height/width ratio as the main data frame so that the exact same graticules will show up in your graticule icon that would have shown up on the map itself had you placed them there. In this case the main page is 8.5 by 11 inches, so the secondary data frame is .77 by 1 inch.

The graticules, from Natural Earth data, are placed in this data frame and styled as thin gray lines, and the data frame is placed in the corner of the map along with the cardinal direction indicators in a nice serif font with matching gray font color.

As a side note, if anyone has seen this technique on any other existing maps please let me know as I have not yet come across it, and I would edit the “new” out of the title of this post accordingly.

January 6th, 2017

I’ve been using a new vector tile style editor to create some maps. The editor is called Maputnik and is still in early development, but it is usable even at this early stage. I’m really impressed with how much of the mapbox gl js spec has been implemented and the multitude of complex tasks that it makes easy.

Here’s a couple of screenshots from a style I’m working on called Camo:

screenshot1 screenshot2

Notes on a Map

November 3rd, 2016

I like to keep a Google Doc full of inspiration maps for whatever projects come up. Here’s one that’s in my inspiration doc and a few notes on techniques that are de rigueur in journalism mapping. 




Overall, this map by The Washington Post is clean and crisp. The hillshade is very subtle but not non-existent. We have an area indicated by dark gray shading and labeled straight on the map with a dark gray label. This is a good reminder that sometimes a map key isn’t needed if you can label the item(s) directly on the map.

They’re using a thin white halo around the place names in the main map (note halos are not present around “SYRIA” in the inset though I’m not sure if that was intentional). All caps are used for country names in bold black. We have bold black mixed case for major cities and regular black mixed case for minor cities. Blue italic serif font is used for the water feature labels. This constitutes a nicely executed, normal, typeface hierarchy.

The main two things that I really want to point out here, though, are the arrows and the arrow labels. The arrows indicate movement by means of gradual increases in arrow thickness, arcs, and gray drop shadows. Each arrow label matches the color of the arrow that it labels. This “pattern” of using arrows in this manner is something I’ve only recently taken note of, whether this means they are a newish development in map styling or not, I think they’re very effective.

British Library Maps, After-hour Tour

November 1st, 2016

The British Library in London is holding a contest to win an after-hours Maps and the 20th Century: Drawing the Line exhibition tour. The competition is free to enter and open until the 11th of November 2016 (midnight).

Competition Entry Form

The library sent me some additional information:

Five lucky winners and their guests will enjoy a tour with the exhibition curator and a special show and tell of rare maps from our collection, including cartographic gems like the personal maps of the kings and queens of England, the earliest maps of London and New York, and secret spy maps from the 17th century. Winners can quiz our curator on the stories behind our maps and hear how different items are selected for our exhibitions.

If I were anywhere close to this exhibit I would definitely want to enter this. Good luck to those who do!

Cartographer's Toolkit

Map Making Tips, Tricks, and Inspiration