HSC Geography cheat sheet

Four biophysical components of an ecosystem: atmosphere, hydrosphere, lithosphere, biosphere; each stores and transfers matter and energy.

Ecosystem functioning is described through energy flows (solar input, trophic transfer, ~10% ecological efficiency), nutrient cycles (carbon, nitrogen, phosphorus), and feedback loops.

Primary productivity: gross primary production minus respiration equals net primary production; NPP sets the energy available to consumers.

Spatial concepts: location (absolute vs relative), distance (linear and time-space), scale (local to global), distribution (density, concentration, pattern), and region.

Population dynamics: change equals (births minus deaths) plus (immigration minus emigration); natural increase rate equals CBR minus CDR per 1,000.

Demographic Transition Model stages: high stationary, early expanding, late expanding, low stationary, and a possible declining stage.

Urbanisation processes: suburbanisation, counter-urbanisation, gentrification, and urban consolidation each alter population distribution within a city.

Human wellbeing indicators: HDI combines life expectancy, education (mean and expected years), and GNI per capita; it is a composite, not a single measure.

Map scale conversions: 1:25,000 means 1 cm on map equals 250 m on ground; 1:100,000 means 1 cm equals 1 km.

Large-scale maps show small areas in high detail; small-scale maps show large areas with less detail.

Contour rules: closely spaced contours indicate steep slopes; contours crossing a valley form a V pointing upstream; hachures mark depressions.

Gradient equals vertical rise divided by horizontal run, expressed as a ratio or percentage; convert both to the same units first.

Cross-sections: plot distance along the horizontal axis and elevation on the vertical axis, then transfer contour intersections.

Fieldwork sequence: define a question, form hypotheses, design sampling (random, systematic, stratified), collect data, analyse, and evaluate reliability and validity.

Data types: primary (collected in the field) vs secondary; quantitative vs qualitative; discrete vs continuous.

Central tendency and spread: mean, median, mode, range, and standard deviation summarise field data; correlation does not establish causation.

GIS layers: raster (grid cells, e.g. satellite imagery) vs vector (points, lines, polygons); overlay analysis combines layers to reveal spatial relationships.