Generalisation l A map is a two dimensional, scaled down representation of selected geospatial information within a ‘geographical area of interest.’ The size and type of the display medium as well as the map’s intent influences the selection and scaling of information. 1. simplification -> 2. selection -> 3. classification 4. -> symbolization

SYMBOLIZATION ..how do we choose design options? Goal: fast and easy communication

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 (printing = % of black)  Colour:    Has three 'dimensions'  hue: "the visual sensations from 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 interactive colour wheel

Design criteria: 1. Association Symbols should be 'associated' with their features, physically or by function Vegetation green Contours brown Battlefield Winter sports Camping Railway line Colour associations: yellow – sun, bright (cheery!) ; blue – water (calm), etc..

1. Association - Points ‘Iconic’ symbols are common Geometric symbols are more abstract Letters are not used except: H  for Hospital,     P   for Parking and       i   for Information  (why the 'lower case' 'i' ?)

Data downloaded from geogratis.ca

Association – points How is population classified Association – points How is population classified? Nominal, ordinal or interval?

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

Association - lines

Association - Polygons / areas ? How to balance area colour/pattern versus boundary outline ?

Association - polygons

Association – size larger / more important features are symbolised bigger e.g. major river for watersheds

2. Convention most conventions are based on association e.g. blue for water, while others are less obvious, e.g. light red for urban.

Conventional symbols – topographic mapping

3. Qualitative versus quantitative data Qualitative:   shape, pattern, hue*      e.g. soil types, schools versus churches [nominal / categorical] Quantitative:     size, tone, chroma, value      e.g. population densities, city sizes Mixed Example

RED is reserved for importance due to its visual impact ** Red – implies importance: ‘danger’, road signs …

Arcmap – categories v quantities menus

Qualitative (nominal) data

Quantitative (interval) data -> ?

4. Levels of Contrast The variables have different levels of visual power. Symbols that belong to the same general group (e.g. hydrographic features) should contrast more strongly with symbols from another group (such as cultural features). The hierarchy is as follows (most powerful first)        Qualitative:      1. hue            2. shape 3. pattern        Quantitative:    1. size           2. chroma 3. value / tone        In other words, we might use 'hue' to distinguish water features from cultural, and pattern between different types of water features - lakes, swamps etc.. The variables have different levels of visual power. Symbols that belong to the same general group (e.g. hydrographic features) should contrast more strongly with symbols from another group (such as cultural features). The hierarchy is as follows (most powerful first)        Qualitative:      1. hue            2. shape 3. pattern        Quantitative:    1. size           2. chroma 3. value / tone        In other words, we might use 'hue' to distinguish water features from cultural, and pattern between different types of water features - lakes, swamps etc..

contrast

5. Visual Hierarchy Map's purpose determines which visual aspects of the map should be most important. Important elements should be most visually prominent and highest in the visual hierarchy. Base information supports the main message and should be lowest in the visual hierarchy. Scale: country Emphasis: vegetation distribution Scale: forest type Emphasis: parks

6. Other factors: purpose what features are more important in each case …

6. Other factors: cost Colour costs v Monochrome: webpage 1x photocopy 10x ! publication 1000x ! ! 6. Other factors: cost

Summary on symbol design Symbols – design variables: Qualitative Quantitative shape, pattern, size, tone colour - hue, colour – chroma / value Symbols – use of design variables: Association Convention Qualitative or quantitative data Levels of contrast visual hierarchy Output purpose and medium