HOW TO CREATE A SIMPLE CHOROPLETH MAP IN ARCGIS PRO

A choropleth is a type of thematic map (i.e a map that focus on specific themes like population, climate or land use) that uses shading, coloring, or patterns to show the value of a variable across geographic areas such as countries, states, local government areas (LGA) or neighborhoods. 

It answers the question: “How does this value vary by location?”

For example:

• A darker color might show a higher population 
• A lighter color can show a lower rate

Why are choropleth maps important?

1. They Make Data Instantly Visual: Choropleth maps make data easy to interpret even for non -experts. Rather than reading a tables of numbers, users can see patterns immediately.
2. They Help Identify Geographic Patterns: With choropleth map, you can simply spot areas with high or low value, regional cluster, trends related to location (e.g urban vs rural, coastal vs island).
3. It Is Useful for Decision Making: Choropleth map supports policy planning, risk assessment, education and public communication of data.
4. It Is Great for Comparing Areas: They are specially useful when comparing population densities, access to schools or clinic, income levels, crime rates.

HOW TO CREATE A CHOROPLETH MAP IN ARCGIS PRO

Open ArcGIS Pro, start a new project and Load your data

In your catalog pane, drag your polygon shapefile or feature into the map view. E.g Nigeria_states.shp. 

Open the symbology pane

• In the content pane, right click in the layer name and click symbology
• Change the symbology from “single symbol” to graduated colors.
• In the symbology panel, under field, choose the attribute you want to map.

Example: population_density, poverty_rate, e.t.c

Choose a classification method

• Natural breaks(Jenks) – great for highlighting natural groupings
• Quartile- put equal area of areas in each class
• Equal Interval- evenly spaced numeric ranges

Set the number of classes (usually 4-6 for clarity)

Choose a color ramp: Pick a color that fits your themes

• ArcGIS pro has several preset ramps
• Best Practice: Use darker colors for higher values and lighter colors for lower values

Add Map Element

• Switch to layout view (insert layout via the insert tab)
• Add a legend, title, north arrow, and scale bar using insert tab

Export your map

• Go to the share tab
• Click export layout to save your map as PDF, PNG, or JPEG.