📚 Year 11 Edexcel Geography: Formula & Theorem Quick Reference Handbook | Year 11 Edexcel 地理：公式定理速查手册
This concise handbook brings together every essential formula, calculation and key quantitative concept you need for your Year 11 Edexcel Geography exam. From river discharge and gradient to population change and map skills, each section pairs a clear formula with worked explanation to speed up revision and boost confidence in data-response questions.
这本速查手册汇集了 Year 11 Edexcel 地理考试所需的全部公式、计算方法和关键数量概念。从河流流量与梯度到人口变化和地图技能，每个部分都将清晰的公式与解释配对，帮助你快速复习，增强应对数据分析题的信心。
1. River Discharge | 河流流量
Q = A × v
Discharge (Q) is the volume of water flowing through a river channel cross-section per second. A is the cross‑sectional area (in m²) measured across a section of the channel, and v is the mean water velocity (in m/s). The result is expressed in cubic metres per second (m³/s), often called cumecs. In fieldwork, you may measure width and depth at intervals, calculate area, then use a flowmeter to find velocity.
流量 (Q) 是每秒钟通过河道横截面的水量。A 为横截面积（单位 m²），v 为平均流速（单位 m/s），结果用立方米每秒 (m³/s) 表示，常称为 cumecs。实地考察中，你可能需要间隔测量河宽和水深，求出面积，再用流速仪测定速度。
2. River Gradient | 河流梯度
Gradient = Vertical rise ÷ Horizontal run
Gradient describes the steepness of a river channel. On an Ordnance Survey map, find two contour lines along the river’s course; the vertical rise is the difference in height (e.g., 10 m) and the horizontal run is the ground distance between them (converted to metres). The result is often expressed as a ratio (1 : 50) or a fraction.
梯度描述河道的陡峭程度。在 Ordnance Survey 地图上，沿河道选取两条等高线；垂直高差即为高度差（如 10 m），水平距离为两条线之间的地面距离（换算成米）。结果通常用比 (1 : 50) 或分数表示。
3. Birth Rate, Death Rate and Natural Increase | 出生率、死亡率和自然增长
Birth Rate = (Number of live births ÷ Total population) × 1000
Death Rate = (Number of deaths ÷ Total population) × 1000
Natural Increase = Birth rate − Death rate
Birth and death rates are standardised per 1000 people to allow comparison between countries of different sizes. When the birth rate exceeds the death rate, there is natural increase; when the reverse happens, natural decrease occurs. The natural change (without migration) can be left as a rate per 1000 or converted into a percentage.
出生率和死亡率以每千人为单位进行标准化，便于不同规模国家之间进行比较。出生率高于死亡率时出现自然增长，反之则为自然减少。自然变化（不含迁移）可保留为每千人的数值，也可以转换为百分比。
4. Population Growth Rate (Including Net Migration) | 人口增长率（含净迁移）
Population Change = (Births − Deaths) + Net Migration
Net Migration = Immigrants − Emigrants
Growth Rate (%) = (Population Change ÷ Population at start of period) × 100
To understand overall population dynamics, combine natural change with net migration. A positive net migration adds to the population; a negative figure signals net emigration. The growth rate is typically expressed as a percentage for annual or decadal change and is vital for evaluating development indicators and demographic transition.
要理解整体人口动态，需将自然变化与净迁移相加。净迁移为正则人口增加，为负则表示净迁出。增长率通常以百分比表示年度或十年变化，对于评估发展指标和人口转型至关重要。
5. Population Density | 人口密度
Population Density = Total population ÷ Land area (km²)
Density figures reveal how crowded a country or region is. Be careful to use land area, not total area including water bodies, if specified. Units are people per square kilometre. Apart from the simple arithmetic mean, exam questions might ask you to calculate density for an outlined area on a map, combining grid skills.
人口密度显示一个国家或地区的拥挤程度。请注意，如果题目说明，应使用土地面积而非包含水体的总面积。单位为每平方公里人数。除简单算术平均外，试题可能要求结合地图技能计算划定区域的人口密度。
6. Dependency Ratio | 抚养比
Dependency Ratio = [(Population 0–14 + Population 65+) ÷ Population 15–64] × 100
The dependency ratio compares the economically 'dependent' age groups (young and old) with the working-age population. A high ratio places pressure on social services, health care and pensions. When interpreting graphs or population pyramids, you frequently need to extract these three age bands and apply the formula.
抚养比将经济上“受抚养”的年龄组（幼年与老年）与劳动年龄人口进行比较。高抚养比给社会服务、医疗和养老金带来压力。在解释图表或人口金字塔时，常需提取这三个年龄段的数据并应用公式。
7. Urbanisation Level | 城市化水平
Urbanisation (%) = (Urban population ÷ Total population) × 100
Urbanisation level measures the proportion of people living in towns and cities. It is also used to calculate the rate of urbanisation over a time period using the percentage change formula (see Section 9). Contrast with counter‑urbanisation, where the urban percentage may fall.
城市化水平衡量居住在城镇和城市的人口比例。也可用百分比变化公式（见第9节）计算特定时期的城市化速率。逆城市化现象则表现为城市人口比例下降。
8. Gross Domestic Product (GDP) per Capita | 人均国内生产总值
GDP per capita = Total GDP ÷ Total population
This indicator divides a country’s total economic output by its population, giving a rough average of individual prosperity. Values are commonly quoted in US dollars. It does not reflect income distribution. For more accuracy in development geography, you might also encounter GNI per capita, but the calculation principle is identical.
该指标将一个国家的经济总产出除以人口数量，粗略反映个人的平均富裕程度。数值通常以美元表示。它无法体现收入分配状况。在发展地理学中，你可能还会遇到人均国民总收入 (GNI)，但计算原理相同。
9. Growth Rate of a Variable | 变量的增长率
Percentage Change = [(New value − Old value) ÷ Old value] × 100
This universal formula is used for GDP growth, population change, urban expansion and many other time‑series data sets. Always identify the starting (old) and ending (new) values correctly. A negative result indicates a decrease. When calculating over multiple years, consider using the compound annual growth rate only if specifically required by the question.
这个通用公式适用于 GDP 增长、人口变化、城市扩张及许多其他时间序列数据。务必正确识别初始值（旧值）和最终值（新值）。负值表示下降。计算多年变化时，仅在题目特别要求时才使用复合年增长率。
10. Map Scales and Distance Calculation | 地图比例尺与距离计算
Actual distance = Map distance × Scale factor
On an Ordnance Survey map (e.g., 1:25 000 or 1:50 000), 1 cm on the map represents 25 000 cm (0.25 km) or 50 000 cm (0.5 km) on the ground. Use a ruler to measure straight‑line distances; for curved features (rivers, roads), use a string or the edge of a paper strip, then measure against the linear scale. Always convert carefully to the required unit, such as kilometres or metres.
在 Ordnance Survey 地图上（如 1:25 000 或 1:50 000），图上 1 cm 代表地面 25 000 cm (0.25 km) 或 50 000 cm (0.5 km)。用直尺测量直线距离；对于弯曲地物（河流、道路），可使用细线或纸条边缘，再对照直线比例尺。务必仔细换算为所需单位，如公里或米。
11. Area Measurement on Maps | 地图面积测量
Estimated Area = (Full grid squares + ½ partial squares) × Area of one square
To estimate the area of an irregular feature (a lake, woodland, urban settlement) on a grid map, count the number of complete squares covered by the feature. For squares that lie partly inside, count every two partial squares as one full square. Multiply the total equivalent squares by the real‑world area of one grid square (e.g., on a 1:25 000 map, a 1 cm grid square represents 0.0625 km²). This method is common in GCSE fieldwork and exam data‑response questions.
要估算网格地图上不规则地物（湖泊、林地、城镇）的面积，数出完全被该地物覆盖的方格数量。对于部分覆盖的方格，每两个算作一个完整方格。将等效方格总数乘以一个方格代表的实际面积（例如 1:25 000 地图上，1 cm 网格方格代表 0.0625 km²）。此方法在 GCSE 实地考察和数据分析题中常见。
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