Cartography and Mapping
This domain tests map design, scale, and map content, including record-of-survey and ALTA/NSPS requirements. Expect questions on representative fractions, contour intervals, north references, and required map elements.
Core rules
- Scale is a representative fraction, such as 1:1,200. A large-scale map shows more detail over a smaller area; 1:1,200 is larger than 1:24,000.
- A scale bar remains valid if a map is enlarged or reduced; a numeric RF does not unless the map is rescaled.
- Contour interval is chosen from terrain, scale, and purpose. Steep terrain needs a larger interval to avoid overcrowding.
- North references include true north, magnetic north, and grid north. State magnetic declination with its date.
- Record of survey content under B&P section 8764 includes title, scale, north arrow, basis of bearings, date of survey, and the surveyor's statement.
- ALTA/NSPS surveys add Table A items and show both record and measured evidence.
Worked example
A map is drawn at 1 in = 100 ft. The representative fraction is 1:1,200 because 100 ft = 1,200 in. On a 2 percent slope, the ground distance between 2-ft contours is 2 / 0.02 = 100 ft, which plots as 1.0 in. A 2-ft interval is therefore readable at this scale.
Traps
- Mixing feet and inches when computing the RF.
- Omitting the basis of bearings.
- Showing magnetic north without a declination date.
- Labeling vertical exaggeration without showing the calculation.
- Confusing a small-scale map with a large-area map.