Geospatial Visualization Design AI Prompt

Design an effective geospatial visualization for this data.

Data: {{data_description}} (geographic level: country, region, state, city, zip code, lat/lon)
Metric to show: {{metric}}
Key question to answer: {{question}}

1. Map type selection:

   Choropleth map:
   - Colors geographic regions by a metric value
   - Best for: showing variation in a metric across well-known geographic boundaries
   - Danger: choropleth maps are biased toward large areas — large regions dominate perception even if their values are typical
   - Fix: use a cartogram or pair with a bar chart for small-area analysis

   Proportional symbol map:
   - Places circles or shapes at each location, sized by the metric value
   - Best for: showing absolute counts or totals where geography is context, not the unit
   - Better than choropleth for showing concentration vs dispersion

   Dot density map:
   - Places one dot per N events at the event location
   - Best for: showing distribution of individual events (crime incidents, store locations)
   - Reveals clustering that choropleth aggregation hides

   Flow map:
   - Arrows showing movement between origins and destinations
   - Best for: trade flows, migration, commuting patterns
   - Danger: quickly becomes unreadable with many flows — limit to top 10–20

   Heat map (geographic):
   - Continuous color gradient showing density of events
   - Best for: high-volume point data where individual dots overlap

2. Choropleth design:
   - Color scale: sequential for single direction (more → less). Diverging for above/below baseline.
   - Classification scheme:
     - Quantile: equal number of areas in each class — good for comparing areas to each other
     - Natural breaks (Jenks): class breaks at natural data gaps — good for showing clustering
     - Equal interval: mathematically equal class widths — good for absolute scale comparison
   - Number of classes: 5–7 classes for most maps
   - Projection: choose a projection appropriate to the geographic extent
     - World maps: Robinson or Winkel Tripel (avoid Mercator for choropleth — distorts area)
     - Country maps: use a projection that preserves area for that country

3. Accessibility for maps:
   - Color: always pair color with a supplementary encoding (pattern or label) for colorblind users
   - Tooltip: rich tooltips with exact values on hover
   - Table alternative: provide a sortable table of the data alongside the map

4. What maps cannot show:
   - Causation or correlation between geographic proximity and outcomes
   - Temporal patterns (use small multiples of the same map, or an animated time series)
   - Non-geographic relationships (use a chart, not a map)

Return: map type recommendation with rationale, color scheme specification, classification method, projection, and tooltip design.