Setting Free the Map
Some places make for challenging map making. In this post we look at one way of working with the dragonfly data to produce a (hopefully) effective map.
In a previous post we looked at massaging some spatial data from Wallis and Futuna to make them mappable. One of the end results of those data was a map that will go into a journal article to communicate where all the dragonflies were observed. We saw previously where the island group is roughly:
As we zoom in closer, we can see where they sit within the area between Fiji and Samoa:
(interestingly, this next map makes me think that the islands are split between Melanesia and Polynesia but from what I can tell, the country is mainly thought of as Polynesian)
By User:Kahuroa – Outline: File:World2Hires filled mercator.svg; Map information based on Vaka Moana: Voyages of the Ancestors – the discovery and settlement of the Pacific, ed K.R. Howe, 2008, p57., Public Domain, https://commons.wikimedia.org/w/index.php?curid=61904861
But I digress… The first challenge is posed as soon as I try and set up a map that shows all of the observations across both of the main island groups:
At this scale (~1:700,000) I can’t really show very much detail – most of the map is empty space and this doesn’t really work. So, my next option was to use two separate maps that would allow me to zoom in to each island group and show more meaningful detail. With Pro, we can handle this by having two map windows (Insert tab > New Map):
I’m showing them here as side by side map windows but they could just as easily be stacked. Two separate maps is going to allow me to get both sets of islands on a layout with sufficient detail to see where they are. I’m using the exact same layer on both maps – in fact I copied it from one and pasted it into the other. If I wanted to, I could symbolise them differently, no problem. Next, I’ll add those to a Layout and see how they fit (Insert tab > New Layout with a A4 portrait chosen):
Not very pretty, but it’s a start. I’d like to adjust the extents so that no island parts are cut off. To do this, I can click on one of the map frames, right-click and choose Activate. Then I can pan and zoom the map around to suit:
When I’m finished, I click Close Activation from the Activated Map Frame tab. Still not very pretty but we’re getting there. I’m feeling the need for a locator map to give things some better spatial context, so I’ve added a third map for this. The scale makes it difficult to see the islands so I quickly spun up a point layer and labelled it with the island names:
This is helpful, but I think an even wider context would be useful, so another map goes on to show the wider Pacific:
Right – I think the guts of it are here – I’ll add some scale bars and a compact legend – this map will end up as a figure in a journal article so I’m not going to worry about a title and keep it as simple as possible. At this point, I can’t say that I’m very happy about this map…but I sent it off to my colleague, Milen, for some comments so that I could focus on something else. Here’s what I sent:
Okay, I do cringe about letting this loose on the world. It’s like an unfinished demo song that leaks out on the internet…pretty crap actually. Milen suggested a few things: add the island names and perhaps swap their positions so the map reflects their actual positions better.
Giving it a bit of thought, I realised that the main thing I didn’t like about this was that it was in portrait orientation – maybe landscape would give me some better opportunities? From the layout properties I switched it over to Landscape:
And worked through it this way:
(Forgot to tell you that I added in some transects, the blue lines, as well…sorry.) Some things I like about this version – the islands are similar on the page to how they are spatially in reality, but I’m not sure I like a locator map in the upper left-hand corner – this is one of the first places people will look and having it there might place too much emphasis on it; it’s a secondary element after all. To keep things simple, I thought I’d have just one scale bar on the map – to honour this, I had to set the scales for both island maps to be the same and then trial and error shaped the map windows til they fit well. I’m counting on my reader assuming that the scale bar relates to the two island maps and not the two locator maps, which each (of course) have their own, very different, scale. That might be what’s called an heroic assumption. (For that matter, I’m assuming my reader will know that north is “up”.) Milen prefered an explicit scale for each island map so I added them:
Almost there methinks, but not quite. In a fit of rearrangement (Ed. more like a spasm…), the next version was pretty much the final version:
There were a few little tweaks in there that I haven’t mentioned but my aim here was to talk through the design problems one often faces with maps. I rattle on to my students about maps being just another, visual, form of communication and it pays to think hard about how effective your maps are. My aim was also to show that developing maps is often an iterative processes between the cartographer and the map reader. I wanted to ensure that it was fit for purpose and that meant running it by Milen enough times to make sure we agreed. We saw something similar when making a tourism map previously.
From a design point of view, a few things I’d like to highlight:
- Both the locators maps are smaller (and therefore attract less attention) than the main maps – they are also roughly the same size and position on the page;
- The vertical margins of the locator map on the right match those of the map above it;
- The main maps are closer to the top of the page and larger, helping to highlighting their importance. Left to right, they match the positions of the islands’ actual positions;
- Both the island maps are at the same scale – this is less important since they each have their own scale bar, but it soothes my OCD that the scale bars are the same size – now my reader doesn’t have to stretch too much in comparing distances between the two;
- I’ve tried to maintain a consistent spacing between the map boxes and lined them all up so that there is none that sticks out. It’s a small detail which most people would never notice, but when they don’t line up, people DO notice it.
I’d say I’m about 85% happy with this but it is fit for purpose. What do you think?
I often see people spending hours and hours getting a map just right (I’m guilty of that too). As a form of communication, maps need that, but at some point you’ve just got to let it go out into the world. Be free Wallis and Futuna map.