Applying Colour & Style. Christopher Wesson London Borough of Redbridge

Transcription

1 Applying Colour & Style Christopher Wesson London Borough of Redbridge

2 The components of colour Generally, the colours on our maps are made up of combinations of Red Green Blue from light sources such as screens, monitors and projectors. RGB is an attempt to mimic the way our eyes compute the light spectrum Cyan Magenta Yellow K (black) in ink printing based on traditional lithographic printing which uses 4 plates for each of these colours to create combinations. Modern and digital printers still use CMYK but may actually use more inks such as photo black or light cyan

3 The components of colour Each of the colours we perceive can be represented by 3 independent values: Whether an object is red, yellow or any other colour of the spectrum. Think of it as a rainbow. Yet also, if the colour is say red, then it tells us the redness of red saturation The purity of the colour (or how much the colour has been diluted by white). For example, royal blue is more saturated than sky blue luminance The intensity of light coming from the colour, this will diverge from the original colour to either white or black Brightness: for measuring self-luminous objects that emits light (e.g. laptop) Lightness: for measuring reflected light (e.g. from paper)

4 Choosing Palettes

5 Creating colour schemes This refers to the combination of colours that we use on any given map It takes lots of practise and a designer s eye to produce pleasing and effective color schemes But help is on hand as we will see shortly

6 Expected familiarity It is cartographic convention for water features to be coloured (and labelled) blue, for natural or woodland features to be green, etc. Departing too far from this expectation may cause people to struggle to interpret the map Evolved technology Digital workflows have replaced a considerable amount of previous reproduction techniques and offset printing processes So now, with modern computers and software, we can pretty much see what we re going to get, even for printed maps But there are still many colours that are simply not transferrable between RGB (for on-screen) and CMYK (for print), so we must either work in the correct preview mode or accept that some colours may need revising

7 Devices Trend towards OLED screens on mobiles has enabled larger colour gamuts the amount of colour that can be reproduced The HP Envy 17 laptop for example can produce 209% of the common srgb colour space Whereas the Lenovo IdeaPad 320 covers 53% of the same colour space, so has 4x less colours to choose from

8 Paper Colour profiles help to aid reproduction on paper Desktop inkjets print in srgb and paper manufacturers publish profiles online. Whereas the CMYK profiles of FOGRA 27 and FOGRA 39 are common for commercial printing Uncoated papers tend to produce solid, more pastel-like colours. Gloss and photo papers tend to produce richer, bolder colours as well as less defined line/text detail Some good compromises exist but depends on your use perhaps try a coated matt(e) paper or polymer As actual printers vary, it is a good idea to ask for a sample book

9 Choosing colours in software GIS and other software, e.g. web mapping applications, are making our lives easier by making it quicker and easier to test different colour combinations Trial and error is for example a far more efficient method since QGIS introduced a live colour preview, i.e. you can change the colour in the menu and instantly see the result on the map at the same time If you combine this with a professional finishing application such as Adobe Illustrator which can preview the CMYK colour space then you have a very easy and efficient workflow

10 Colour palettes Nominal or qualitative Unique classes of data, e.g. school subjects, or people s names Sequential Indicates the level of a particular variable, from low to high Diverging Has both positive and negative values or connotation, e.g. temperature, or wealth A single numerical field such as a count, percentage or density that can be continuous or discrete

11 I said help was on hand Firstly, there are many websites that will help choose your colour palette, for example color.adobe.com tristen.ca/hcl-picker colourco.de paletton.com colorbrewer2.org

12 What about colour ramps in GIS? So, if you are stuck using an outdated version of GIS, then stick with the web-based tools. Initially, colour schemes in GIS were poor However, latest versions of ArcGIS, QGIS, MapInfo, all have excellent colour schemes built-in

13 Dark maps Everything in reverse!

14 Colour vision deficiency (aka colour blindness) We should choose our colours to be sympathetic towards CVD Bespoke CVD styles are better reserved for extreme cases and bespoke projects, because, just like poor eye sight, there are infinite levels of severity; i.e. there will be far more shortsighted people than there are blind people Colour pairings that are less impacted by CVD include: source: Cartography. Kenneth Field Red and blue Red and purple Orange and blue Orange and purple Brown and blue Brown and purple Yellow and blue Yellow and purple Yellow and grey Blue and grey

15 Mixing

16 Blend modes or compositing When we print in CMYK we mix different inks. We can use the same idea to produce some Remarkable results using transparencies and blend modes in digital mapping Multiply Multiplies the luminance levels of the current layer with those of the layer(s) below, usually resulting in a darkened image tinted to the color of the current layer As in the example (right) Screen Will paint light from the current layer over those layer(s) below. Some consider it to be the opposite of multiply

17 Blend modes or compositing When we print in CMYK we mix different inks. We can use the same idea to produce some Remarkable results using transparencies and blend modes in digital mapping Overlay Uses a combination of the screen blend mode on the lighter pixels, and the multiply blend mode on the darker pixels. It uses a half-strength application of these modes, and the mid-tones (50% grey) become transparent Addition (aka Linear Dodge) This mode simply adds the values from the current layer to the one(s) below. Note as we are adding RGB or light then the colours become whiter (brighter) As in the example (right)

18 Blend modes or compositing This is also useful if we think back to hillshading, if we manually create multi-directional hillshade

19 Map Style

20 But I only make GIS maps There's no such thing as GIS maps...you can do a lot by combining GI Systems with GI Science. One function of which is to make maps. But they're not a special breed. They're just maps, much like you'd make a map using many other tools. It's true that many maps made using GIS have a similar appearance but that's the fault of the person making them because they do not go beyond the defaults. Ken Field, Senior Cartographic Production Engineer at ESRI

21 Style for understanding GIS data dump Styled map

22 Style for understanding

23 Live GIS demo!

24 GIS Analysis: World Oil and UFOs!

25 GIS Analysis: Smart Cities

26 Style includes Text Fonts can emphases a theme

27 Style includes Text

28 SUMMARY The concept of style is applicable to every type of map and deliberately developed style is important not only for aesthetics but also for better perception of the map s geographic data. Giedre Beconyte, Professor at GIS-Centras, Vilnius University

29 Thank