Map Reading, Interpretation and Fieldwork Skills
Scale and grid references
Map scale is the ratio of map distance to ground distance; 1:50,000 means 1 cm represents 0.5 km. Use the linear scale for distance. Four-figure grid references give the grid square, read eastings first then northings; six-figure references add tenths of a square.
Relief and drainage
Contours join points of equal height, and the contour interval is the height difference between them. Closely spaced contours indicate a steep slope; widely spaced contours a gentle one. Spot heights and trig points give exact elevations. Rivers flow downhill, usually at right angles to contours, and V-shaped contours point upstream. Drainage patterns include dendritic, trellis and radial.
Human features and fieldwork
Identify settlement pattern (nucleated, dispersed, linear), land use, communications and services. Fieldwork follows a cycle: aim or hypothesis, sampling design (random, systematic, stratified), data collection (transects, quadrats, questionnaires, flow counts), presentation (bar chart, scattergraph, choropleth, cross-section), analysis, conclusion and evaluation of limitations.
Worked example
A bridge lies within grid square easting 456, northing 789, two-tenths east and four-tenths north. The six-figure reference is 4562 7894: read eastings along the bottom, northings up the side, then interpolate tenths. Gradient is vertical interval divided by horizontal distance in the same units, multiplied by 100.
Traps
Reversing eastings and northings; using map distance as ground distance; ignoring the scale bar; reading contour values downhill; failing to state a limitation of the sampling method.