Cartography, Map Reading, Remote Sensing and GIS
What this domain tests
Questions cover scale, map projections, contour interpretation, remote-sensing platforms and GIS data models.
Core rules
- Scale types: statement, representative fraction (RF) and graphical. RF 1:50,000 means one unit on the map equals 50,000 of the same units on the ground.
- Contours join points of equal elevation. Close contours mean steep slopes; widely spaced contours mean gentle slopes. Contour interval is the vertical difference between adjacent contours.
- Remote sensing records electromagnetic radiation. Passive sensors use reflected sunlight or emitted radiation; active sensors emit their own signal, such as radar.
- GIS stores spatial data as vector (points, lines, polygons) or raster (cells). Layers can be overlaid for analysis.
Worked example
On a 1:50,000 map, 2 cm represents how much ground distance? 1 cm = 50,000 cm = 0.5 km. Therefore 2 cm = 2 × 0.5 = 1 km.
Traps
A small RF denominator means a large-scale map with more detail. Contour lines crossing a valley bend upstream, not downstream. GIS is not the same as GPS; GPS provides location, GIS analyses spatial data. Remote sensing does not replace field verification.