SYMBOLISATION. Generalisation: which / how many features we display.. Symbolisation: how to display them?

Transcription

1 Generalisation: which / how many features we display.. Symbolisation: how to display them? SYMBOLISATION General Goal: easy and effective communication based on design principles and common sense as much as rules

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3 Universal STOP sign

4 Visual Design Variables Shape: the detail or outline of a point Pattern: regular repetition of shapes Texture: variation of tones or lines Orientation: direction of symbol element Size: size in a point, or width of a line Tone: shades of gray Colour: hue Has three 'dimensions' (wavelength) chroma (saturation) value (intensity)

5 Visual Design Variables Shape: the detail or outline of a point Pattern: regular repetition of shapes Texture: variation of tones or lines Orientation: direction of symbol Size: size in a point, or width of a line Tone: shade of gray ( % of black) Colour: Has three 'dimensions' hue: "the visual sensations from different wavelengths of light " e.g. red, blue chroma: saturation or intensity = tints, e.g. pale v solid blue value: purity or lightness = shades, e.g. blue, blue/black

6 The electro-magnetic colour spectrum the longest wavelengths of light (red) are the least refracted

7 Chroma / saturation and value / intensity

8 Munsell color chart (hue-saturation-intensity) for soils - and also used for beers Saturation ->

9 hue - basic colour we perceive, eg 12 step wheel value - lightness or darkness. Can be hard to perceive variations in value saturation - intensity or purity compared to a neutral gray

10 Design criteria: 1. Association Vegetation green Contours brown (except on ice ) Battlefield Winter sports Camping Railway line Symbols should be 'associated' with their features, physically or by function

11 Shape: Iconic and abstract symbols Iconic (pictorial) Abstract (choice may depend on map purpose and space available)

12 Association - Points Iconic symbols are common -> Letters are not used except for: H Hospital P Parking i Information (why the 'lower case' 'i'?)

13 Association - Lines 'permanent' physical features are shown as solid. e.g. rivers, roads Less certain features are shown in broken lines. e.g. intermittent streams, trails Administrative boundaries use a dot-dash pattern

14 Association - Polygons/areas ArcMap default patterns Do NOT believe all the defaults?

15 Polygons / areas Colour or pattern fill? Outline colour? Both? Fill Transparency (0-100%)?

16 Polygons / areas Use of fill v outline v both depends on: meaning / significance of area edge Rivers and lakes: outline (+ colour fill) Park boundary: outline / no fill? Forest /vegetation: fill only (no outline) Size: small - fill (+outline) large - outline only

17 Example 1 Note: No polygon outlines for vegetation, outlines only for regions

18 Example 2: PGmap use of area transparency but outline only might be better Note: No polygon outlines for vegetation, outlines only for regions

19 Example 3: Assignment 1- good line width contrast (streams still too thick)

20 Design criteria: Colour association Colour associations: physical and psychological Yellow sun, bright (cheery..) ; Blue water, calm, cool etc.. Red heat, danger, blood Green vegetation, parks, recycling, envy..

21 Association size larger / more important features e.g. road width

22 Using visual variables ensure good contrast GIS software applies colours by attribute sometimes too many categories or values Example: Unsuccessful forest classification (primary species) colours: too many similar tints/shades of the same hue

23 2. Convention symbols e.g. topographic mapping

24 Canada NTS conventions Green vegetation Red roads Orange - minor roads Black buildings Urban pink (why pink?)

25 Venice, satellite image Most conventions are based on association e.g. blue for water, while others are less obvious, e.g. light red for urban.

26 3. Qualitative versus quantitative data Qualitative: [nominal / categorical] HUE *, shape, pattern e.g. soil types, schools versus churches * see next slide Quantitative: [interval] SIZE, tone, chroma, value e.g. population densities, city sizes

27 RED is reserved for importance due to its visual impact - as it has the longest wavelength and advances (blue retreats) ** Red implies importance: / danger (roads)

28 Yellow is next to red in the colour spectrum

29 Qualitative (nominal/categorical) data

30 ->? Quantitative (interval) data

31 ArcMap categories v quantities menus

32 Colour ramp for quantitative data (good example)

33 Poor use of colours and size

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35 4. Other factors: map purpose what features are more important in each case

36 5. Other factors: cost and media Colour costs v Monochrome: - In this case, colour could be avoided webpage 1x photocopy 10x publication 1000x Don t use colour, just because you can

37 More on colour. colour blindness. 7% of men and 1% of women

38 Summary on symbol design Symbols design variables: Qualitative shape, pattern, colour - hue Quantitative size, tone colour chroma / value Symbols use of design variables: 1.Association 2. Convention 3.Qualitative or quantitative data 4. Output purpose, cost and media Much of this is intuitive common sense..