Dot and choropleth maps

Thematic (distribution) maps show regional patterns of one theme. They can be quantitative (amounts) or qualitative (kinds).

Dot maps show distribution by placing dots of equal size and fixed value over each area. Example: at 1 dot = 1,00,000 people, a district with 23,40,000 people gets about 23 dots. Place fewer dots in mountains, deserts and snow-covered areas, where few people live, and more in the plains and towns.

Choropleth maps shade administrative units (states, districts) according to a rate or ratio: density, literacy, sex ratio. Darker shades usually mean higher values.

To make classes for a choropleth: find the range (highest − lowest), and divide it by the number of classes. For five classes, interval = range ÷ 5. Example: if literacy ranges from 50 to 95 per cent, the range is 45, so the interval is 9: 50-59, 59-68, and so on.

Dots for counts, shades for rates.