Symbology Flashcards
(15 cards)
What is a map symbol?
A visual mark representing data/concepts (e.g., shapes, colors).
How do symbols differ by relationship?
Shapes vary by data type (e.g., △ for parks, □ for buildings).
What are resemblance symbols?
Symbols mimicking real objects (e.g., ✈ for airports, 🔴 for danger).
Why follow symbol conventions?
Avoid confusion (e.g., blue for water, ⛪ for churches).
How does size/shape vary in symbols?
Size = quantity, Shape = quality/type.
When to use proportional symbols?
For absolute point data (e.g., city populations), not densities/ratios/rates
What is absolute scaling?
Symbol size matches exact data values (e.g., 1,000 people = 1,000-unit circle).
Why use perceptual scaling?
Corrects human underestimation of large symbols.
Graduated vs. proportional symbols?
Graduated: classed ranges; Proportional: unclassed raw values.
Best symbol shape?
Circles (visually stable); squares (easier area calculation).
Dot map advantages?
Shows spatial variation; allows multi-phenomena overlay (e.g., colored dots).
Dot map disadvantages?
Dots may merge; random placement can misrepresent patterns.
How to design symbol sets?
Maximize distinctness; prioritize hierarchy (theme > base info).
Pie vs. bar chart maps?
Bar charts easier to compare lengths; pies show proportions.
What’s true point data?
Actual locations (e.g., cities). Conceptual = aggregated data (e.g., state GDP at capital).
