11. Mapping and Cartography
Mapping and Cartography
This domain tests map scale, projection, generalisation, symbol design and map metadata. Expect calculations of scale and area, and judgement about what a map can and cannot show.
Core rules
- Scale is map distance divided by ground distance; a 1:10,000 map has 1 cm representing 100 m.
- Area scales by the square of the linear scale; a 1 cm2 map area represents 10,000 m2 at 1:10,000.
- Generalisation simplifies features for legibility; it must not create false topology.
- Projection, grid, datum and north direction must be stated on a professional map.
- Symbolisation should match the map purpose and user; metadata supports discovery and reuse.
Worked example
On a 1:25,000 map, a measured 4.0 cm line represents 4.0 cm x 25,000 = 100,000 cm = 1,000 m. A rectangular parcel measuring 2.0 cm by 3.0 cm on the map has map area 6.0 cm2. Ground area = 6.0 x (25,000)^2 cm2 = 6.0 x 625,000,000 cm2 = 3.75 x 10^9 cm2 = 375,000 m2 = 37.5 ha.
Traps
Applying the linear scale to area; using a photocopied bar scale without checking reproduction; confusing grid north with true north; over-generalising small parcels; omitting datum metadata.