Practical Cartography: Texture

I am making a last-minute scheduling change: This week was supposed to be the debut of the first Made-For-Maphugger map, but it needs a bit more development time. Welcome instead to the first of MapHugger’s practical cartography essays- writings geared for the ‘on-the-ground’ aspects of designing unboring maps.

Let’s talk about texture.

The word ‘texture’ has a lot of meanings, including some pre-existent meanings within cartography (it’s synonymous with ‘pattern fill’), but I’m referring to a specific sense of the word texture, that is: overlays designed to break up the flat panes of color within an image, and give it a richer or weathered appearance.

Texture is a super-common thing to see in digital illustration and graphic design, but is almost unheard of in modern digital-made maps. And that’s a shame! Because it’s a relatively simple graphical flourish that adds a lot to the appeal of an image.

ABOVE: This blog’s illustrious logo, in flat and textured versions.

In fairness, I can identify a few reasons why texture isn’t common in cartography, or maybe reasons why you may not want to use texture in a map:

•  Care must be taken so that texture does not obfuscate data. If you are dealing with a choropleth map, for instance, you don’t want a blob of color making one map feature look dissimilar from other map features in the same class. People already have enough problems with simultaneous contrast.
• It might be even worse if you’re working with shaded relief or hypsometric tints. Any texture you could add would be impossible to visually disentangle from the nuanced texture that already exists in the relief.

ABOVE: Phony landscape features appear when I overlay some texture onto this hypsometric tint of the Tibetan Plateau.

• The second reason has to do with vector/raster. Textures are almost always done via raster, while maps are generally vector. Mapmakers are probably none too keen on adding raster post-production to their maps, because it means having to jump over to a program they’re probably less familiar with. More important, probably: if you have a raster overlay on top of a vector image, the image is no longer infinitely scalable. Mapmakers are super fond of printing their works at poster size, and to keep your map properly printable at that big a scale you’d need a really high-res raster. Even if you had no qualms with restricting your map like that, and you knew where to locate such a high resolution raster, adding it on top of your map would bump up the filesize quite a bit.

That’s not to say that maps can’t look really awesome with texture, though! Some nice examples:

ABOVE: ‘World Map of Inventions’ - Owen Gatley, 2011. Impeccable flourishes.

BELOW: ‘United States of Baseball’ – Nike, 2007. The texture here warms the map up nicely.

So anyway, getting texture onto an image falls decidedly into ‘easy to learn, difficult to master’ territory. The first step is going to be to site some overlays to use. There’s plenty of websites dedicated to giving out good, hi-res textures such as Lost & Taken, LoveTextures, and TextureWarehouse. An alternative is to create your own. Take photographs of walls/concrete. You can also make your own by scanning things, like weathered paper or things you’ve scribbled on with paints/markers. It’s not hard actually! Just keep sourcing textures when you find or search for them, and you’ll build up a very usable collection.

Once you have something to use, just pop open your image and your textures in your favorite raster program, and slap ‘em on a new, semitransparent layer.

Getting the textures to look nice though requires a bit of fiddling around. Some things to play around with:

• Scaling: Pan and zoom your texture around so it fits nice. If you’re too ‘zoomed in’ on your texture, it will look chunky. Too far out, and it’ll be too fine.
• Levels: It’ll be very common that the texture image you bring in will introduce too much contrast to your image, or maybe doesn’t have enough contrast. Look under your color or image adjustment options for a ‘brightness/contrast’ or ‘curves’ tool, which will let you fine tune the darkness and contrast of your image.
• Color: Unless your textures are in greyscale, they will ‘tint’ your final image. This can sometimes be a nice effect, actually, but if you don’t want texture to mess with your carefully selected hues, run them through the greyscale filter.
• Blending Mode: Pretty much every graphics program will let you select from different overlay modes for the layer – multiply, color burn, etc. I’ll spare you a description of each of these, since it’s better just to trial & error your way through them.
• Masks: You may want only parts of your image to be covered with a certain texture, or the texture to overlay differently over different items. This is easy to pull off with judicious use of the magic wand tool.
• Other Filters: You can modify your textures further by running image filters on them. Vignettes, art filters, what-have-you. I consider it a bit of a business secret, but one that I personally use a bunch is a halftone filter, as seen below.