📚 Edexcel GCSE Geography Formula & Theorems Quick Reference | Edexcel GCSE 地理公式定理速查手册
This quick reference guide breaks down the essential formulas, calculations, and theoretical models you need to master for the Edexcel GCSE Geography exam. From drainage density to population change and urban models, every key equation and concept is explained simply, with step-by-step examples. Understanding these tools will sharpen your data analysis skills and help you answer investigation, fieldwork, and decision-making questions accurately.
本速查手册为你拆解 Edexcel GCSE 地理考试必须掌握的核心公式、计算方法和重要理论模型。从排水密度到人口变化再到城市模型，每个关键公式和概念都用简单明了的方式解释，并配有分步示例。掌握这些工具将提升你的数据分析能力，帮助你准确回答调查、实地考察和决策类题目。
1. Drainage Density | 排水密度
Drainage density (Dd) measures the total length of stream channels per unit area of a drainage basin. It reveals how well a basin is drained and indicates the influence of geology, slope, and land use.
排水密度（Dd）衡量流域内单位面积上河道总长度。它能揭示流域的排水效率，并反映地质、坡度和土地利用的影响。
Dd = L ÷ A
Where L = total length of all streams (km) and A = area of drainage basin (km²).
其中 L = 所有河流总长度（千米），A = 流域面积（平方千米）。
A high density (e.g. > 2.0 km/km²) suggests impermeable rock, steep slopes, and high rainfall, producing rapid runoff and a flashy hydrograph. Low density (e.g. < 0.5 km/km²) points to permeable rock, gentle relief, and more infiltration.
高密度（如大于 2.0 km/km²）表示不透水岩石、陡坡和高降雨量，产流迅速，洪水过程线陡涨陡落。低密度（如小于 0.5 km/km²）则指向透水岩石、平缓地形和更多下渗。
2. River Gradient & Slope | 河流梯度与坡度
Gradient describes the steepness of a river channel or valley side. It is used in river profiles and slope stability analysis.
梯度描述河道或谷坡的陡峭程度，用于河流剖面分析和边坡稳定性研究。
Gradient = Vertical Rise (m) ÷ Horizontal Distance (m)
To express as a percentage, multiply by 100. Fieldwork often calculates gradient between two points along a river: measure the change in elevation (Δh) and the distance along the ground or valley.
若要表示为百分比，乘以 100 即可。野外考察常计算河流两点间的梯度：测量高程变化（Δh）和地面或河谷长度。
Example: If a river falls 15 m over a 300 m reach, the gradient is 15/300 = 0.05, or 5%.
示例： 如果某段河流在 300 米距离内下降 15 米，则梯度为 15/300 = 0.05，即 5%。
3. Birth Rate and Death Rate | 出生率与死亡率
Crude Birth Rate (CBR) and Crude Death Rate (CDR) are fundamental indicators of population change. They are expressed per 1000 people per year.
粗出生率（CBR）和粗死亡率（CDR）是人口变化的基本指标，以每年每千人中的发生数表示。
CBR = (Number of live births ÷ Total population) × 1000
CDR = (Number of deaths ÷ Total population) × 1000
Mid-year population is usually used. These rates help classify stages of the Demographic Transition Model (DTM).
通常使用年中人口数。这些比率有助于划分人口变迁模型（DTM）的各个阶段。
4. Natural Increase & Migration Growth | 自然增长与迁移增长
Population growth can be decomposed into natural change and net migration. Natural increase is the difference between births and deaths.
人口增长可分解为自然变动和净迁移。自然增长是出生人数与死亡人数之差。
Natural Increase = Births – Deaths
Rate of natural increase (RNI) is often given as a percentage:
自然增长率（RNI）常用百分比表示：
RNI (%) = (CBR – CDR) ÷ 10
Total population growth rate includes migration:
总人口增长率包括迁移：
Growth Rate (%) = (CBR – CDR + Net Migration Rate) ÷ 10
Where Net Migration Rate = (Immigrants – Emigrants) / Population × 1000.
其中净迁移率 = （迁入 – 迁出）/ 人口 × 1000。
5. Population Density & Dependency Ratio | 人口密度与抚养比
Population density expresses how crowded an area is, while the dependency ratio shows the pressure on the productive population.
人口密度表示一个地区的拥挤程度，而抚养比则显示劳动力人口所承受的抚养压力。
Population Density = Total Population ÷ Area (km²)
Dependency Ratio compares the non-working-age population (0–14 and 65+) to the working-age population (15–64).
抚养比将非劳动年龄人口（0-14 岁和 65 岁以上）与劳动年龄人口（15-64 岁）进行比较。
Dependency Ratio = [(Population 0-14 + Population 65+) ÷ Population 15-64] × 100
A higher ratio indicates greater economic burden on the workforce, typical of developing countries with youthful populations or ageing developed countries.
比率越高，劳动力经济负担越重，常见于年轻型人口结构的发展中国家或老龄化的发达国家。
6. Urbanisation Level & Rate | 城市化水平与速率
Urbanisation level is the percentage of a country's population living in urban areas. The rate of urbanisation measures how quickly this percentage changes.
城市化水平是指一国居住在城市地区的人口百分比。城市化速率衡量该百分比的变化快慢。
Urbanisation Level (%) = (Urban Population ÷ Total Population) × 100
The annual rate of urbanisation compares the increase in urban population percentage over time.
年城市化速率比较一段时间内城市人口百分比的增长。
Rate of Urbanisation = (Change in Urban % over period) ÷ Number of years
Rapid urbanisation is typical of emerging economies, while many developed countries already have high urban levels but slow or negative rates.
快速城市化是新兴经济体的典型特征，而许多发达国家城市化水平已很高，但速率缓慢甚至为负。
7. Development Indicators & HDI | 发展指标与人类发展指数
Single indicators like GNI per capita have limitations. The Human Development Index (HDI) combines health, education, and income into a composite measure.
单一指标如人均国民总收入有其局限性。人类发展指数（HDI）将健康、教育和收入结合成一个综合指标。
HDI = (IHealth × I_Education × IIncome)1/3
Each dimension index is normalised:
每个维度指数都经过标准化：
Dimension Index = (Actual Value – Minimum) ÷ (Maximum – Minimum)
Health uses life expectancy at birth; education uses mean and expected years of schooling; income uses GNI per capita (PPP). The Edexcel specification expects you to interpret HDI values and trends, not recalculate, but understanding the logic helps explain why a country's rank changes.
健康维度用出生时预期寿命；教育用平均和预期受教育年限；收入用按购买力平价计算的人均国民总收入。Edexcel 大纲要求你解读 HDI 数值和趋势，不要求重新计算，但理解其逻辑有助于解释为何一国的排名会发生变化。
8. Map Skills: Scale, Distance & Area | 地图技能：比例尺、距离与面积
Ordnance Survey (OS) map skills are tested in Paper 3 (Geographical Investigations). You must be able to read scales, measure straight-line and curved distances, and estimate areas.
英国地形测量局地图技能在试卷三（地理调查）中考查。你必须能够读比例尺、测量直线和曲线距离，并估算面积。
Scale conversion: A scale of 1:50 000 means 1 cm on the map represents 50 000 cm (0.5 km) on the ground.
比例尺换算： 1:50 000 表示图上 1 厘米代表实地 50 000 厘米（0.5 千米）。
Real Distance (km) = Map Distance (cm) × Scale Factor ÷ 100 000
For curved features like a river, use a piece of string or paper, then measure against the linear scale bar.
对于河流等弯曲地物，可用细线或纸片沿曲线摆放，然后对照直线比例尺测量。
Area of regular shapes: Area = Length × Width (converted using scale). For irregular areas, count grid squares and apply the area of one square (e.g. a 1 km grid square on a 1:50 000 map is 1 km²).
规则图形的面积：面积 = 长 × 宽（按比例尺换算）。对于不规则区域，数方格并乘以单个方格的面积（如 1:50 000 地图上 1 千米网格的方格面积为 1 平方千米）。
9. Key Geographic Models & Theorems | 重要地理模型与定理
Several conceptual models act as 'theorems' in geography, helping you explain patterns and processes. Memorising their structure and criticisms is vital for higher-mark questions.
几个概念模型在地理中起着“定理”的作用，帮助你解释空间格局和过程。记住它们的结构及批评观点对高分题目至关重要。
The Burgess Concentric Zone Model (1925) arranges urban land use in rings around the CBD: central business district, transition zone, working-class housing, middle-class housing, commuter zone. It explains urban social segregation based on bid-rent theory.
伯吉斯同心圆模型（1925） 将城市土地利用围绕中央商务区（CBD）排列成同心圆：CBD、过渡带、工人阶级住宅区、中产阶级住宅区、通勤带。它基于地租竞价理论解释城市社会隔离。
Hoyt Sector Model (1939) modifies Burgess by showing wedge-shaped sectors along transport routes. Industrial areas follow railways or rivers; high-class housing develops along roads away from industry.
霍伊特扇形模型（1939） 改进同心圆模型，显示沿交通路线分布的楔形扇区。工业区沿铁路或河流分布；高级住宅沿着远离工业的道路发展。
Harris-Ullman Multiple Nuclei Model (1945) suggests cities grow from several independent nodes, not a single CBD. Specialised districts (e.g. airport, industrial estate, university) attract different land uses.
哈里斯-乌尔曼多核心模型（1945） 认为城市由若干独立核心发展而来，而非单一 CBD。专业区域（如机场、工业园区、大学）吸引不同的土地利用。
The Demographic Transition Model (DTM) outlines five stages of population change based on birth and death rates. It links development with natural increase. Key features: Stage 1 – high fluctuating; Stage 2 – early expanding; Stage 3 – late expanding; Stage 4 – low fluctuating; Stage 5 – decline.
人口变迁模型（DTM） 根据出生率和死亡率描绘人口变化的五个阶段，将发展与自然增长联系起来。关键特征：第一阶段——高高低；第二阶段——早期扩张；第三阶段——后期扩张；第四阶段——低低低；第五阶段——衰退。
Clark-Fisher Model describes the structural change of employment from primary to secondary to tertiary and quaternary sectors as a country develops. It is linked to de-industrialisation and the service economy.
克拉克-费舍尔模型 描述随着国家发展，就业结构从第一产业向第二产业、第三产业和第四产业转变的过程，与去工业化和服务经济相关联。
Published by TutorHao | Geography Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
或截图后用「扫一扫 → 相册」选择本图