---
watermark: ORIRO
disable-model-invocation: true
name: social-geography
provider: ORIRO.ai
copyright: Copyright (c) 2026 ORIRO.ai
description: >
  Human and physical geography — population geography, urbanization, development
  geography, climate geography, and GIS fundamentals. Sources: OpenStax Geography
  (CC-BY), ESRI GIS basics (free), UN data (free).
---

# Human and Physical Geography

## Population geography

**Demographic Transition Model (DTM):**
Stage 1: High birth + High death. Pre-industrial. Slow growth.
Stage 2: High birth + Falling death. Early industrial. Rapid growth. Sub-Saharan Africa.
Stage 3: Falling birth + Low death. Mature industrial. Slowing growth. India, China.
Stage 4: Low birth + Low death. Post-industrial. Near zero growth. Europe, Japan.
Stage 5 (proposed): Deaths > Births. Population decline. Germany, Japan.

**Population distribution:** 90% of humans live on 10% of land. N Hemisphere bias.
**Mega-cities:** 35+ cities with >10 million people. Tokyo (37M) largest.

## Urbanization

**Urbanization rate:** 56% of world population urban (2021). Rising.
**Push factors:** Rural poverty, unemployment, conflict.
**Pull factors:** Jobs, services, social opportunity.
**Urban heat island:** City temperatures 1-3°C higher than surroundings. Dark surfaces + waste heat.
**Informal settlements:** 1 billion people in slums/squatter settlements globally.

## Development geography

**HDI (Human Development Index):** Life expectancy + Education + GNI per capita.
Norway (0.96) highest. Niger (0.40) lowest.
**Gini coefficient:** 0 = perfect equality, 1 = perfect inequality.
World average ~0.35. South Africa highest (~0.63).

## Climate geography

**Köppen classification:**
A = Tropical (rainforest, monsoon, savanna).
B = Arid (desert, semi-arid).
C = Temperate (Mediterranean, humid subtropical).
D = Continental (humid continental, subarctic).
E = Polar.

**Climate vs Weather:** Weather = short-term. Climate = 30-year averages.
**El Niño/La Niña (ENSO):** Pacific Ocean temperature cycle. 3-7 year cycle. Global weather impacts.

## GIS (Geographic Information Systems)

**Raster data:** Grid of pixels. Satellite imagery, elevation models.
**Vector data:** Points, lines, polygons. Roads, boundaries, locations.
**Coordinate systems:** WGS84 (GPS standard), UTM (projected, for measurement).
**Free GIS tools:** QGIS (open source), Google Earth Engine (free for research).

Sources: OpenStax Geography and Environment (CC-BY, free), ESRI GIS basics (free), UN Population Data (free)