Choropleth Maps Flashcards
(16 cards)
What does “BOLTSS” stand for in map interpretation?
Border, Orientation, Legend, Title, Scale, Source.
How to approach interpreting unusual map patterns?
Seek explanations, use as inspiration for exploration, analyze layers for underlying processes.
What are the steps to interpret a thematic map (PQE)?
Observe patterns (P), quantify details (Q), identify exceptions (E), explain using prior knowledge.
What is a choropleth map used for?
Showing spatial variation influenced by boundaries (e.g., GDP per capita).
Key requirements for choropleth map data?
Data must vary spatially and align with enumeration units (not uniform).
How to compare choropleth maps effectively?
Use identical legends; boundaries separate areas but don’t carry values.
Why is map scale important for symbol recognition?
Ensures symbols/patterns are visible and distinguishable.
How does enumeration unit size affect choropleth maps?
Larger units show more detail; varying sizes require standardization (e.g., density calculations).
What issues arise from varying enumeration unit sizes?
Shading may misrepresent data; large areas dominate visually.
How to standardize data for choropleth maps?
Use ratios (e.g., population/area) or rates (e.g., deaths/population).
What does white indicate in choropleth maps?
Missing/no data.
What distinguishes unclassed choropleth maps?
No class intervals; each unique value has a unique shade/color.
What are sequential color schemes?
Same hue with varying saturation (e.g., light to dark blue).
When to use divergent color schemes?
For data centered around a midpoint (e.g., average/zero).
What are qualitative color schemes for?
Categorical data (different hues for different categories).
Can color scheme rules be broken?
Yes, in specific contexts.