100+ Free TASC Geography Level 3 Practice Questions

Explanation: At a scale of 1:25,000, 1 cm on the map represents 25,000 cm (250 meters or 0.25 km) on the ground. Multiplying 8.0 cm by 0.25 km yields an actual ground distance of 2.0 km (8 * 25,000 cm = 200,000 cm = 2,000 m = 2.0 km). The choice showing 0.2 km misplaces the decimal place. The choice showing 20 km miscomputes scale by a factor of 10, while 8.0 km confuses map centimeters directly with ground kilometers.

Explanation: Slope gradient is computed as Vertical Rise divided by Horizontal Distance. Rise = 440 m - 120 m = 320 m. Gradient = 320 m / 1,600 m = 0.20, which equals 20% or a ratio of 1 in 5 (1600 / 320 = 5). Calculating rise as 400 m yields 25% (1 in 4). Using 160 m rise yields 10% (1 in 10). Using 640 m rise yields 40% (1 in 2.5).

Explanation: In GIS, the raster model structures geographic space as a tessellated grid of regular cells (pixels), each containing an attribute value (e.g., elevation, land cover class). The vector model structures features as discrete geometry—points, lines, or polygons—defined by explicit X,Y coordinate pairs. Inverting the raster and vector definitions is incorrect. Stating that raster cannot represent continuous elevation surfaces or vector cannot model property boundaries introduces false constraints.

Explanation: NDVI is calculated using the formula: NDVI = (NIR - Red) / (NIR + Red). Substituting the values gives: (0.60 - 0.20) / (0.60 + 0.20) = 0.40 / 0.80 = 0.50. The value 0.40 represents the numerator (NIR - Red) without dividing by the denominator. The value 0.80 represents the denominator (NIR + Red). The value 0.33 divides 0.20 by 0.60.

Explanation: Temporal resolution refers to the frequency at which a satellite sensor re-visits and acquires imagery over the exact same ground location. For monitoring changes over a 30-year span, multi-decadal repeat frequency (temporal resolution) is primary. While spatial resolution is also important for seeing channel details, temporal resolution guarantees historical time-series availability. Radiometric resolution refers to bit-depth sensitivity, spectral resolution to narrow wavelength channels, and thermal resolution to thermal emissions.

Explanation: V-shaped contour lines that point upstream or uphill toward higher elevations represent a river valley or gully carved by flowing water. Conversely, contour V-shapes pointing downhill toward lower elevations represent a ridge or spur. A sharp mountain ridge or spur is indicated by V-shaped contours pointing downhill towards lower elevation. Widely spaced contours indicate flat terrain, while closed depression contours require hachure marks.

Explanation: Dense forest canopies cause GPS satellite radio signals to bounce off leaves, branches, and damp foliage before reaching the receiver antenna (multipath interference) and weaken signal strength (attenuation), significantly increasing spatial error. Selective availability was deactivated globally in 2000. Geoid undulations and map projection distortion describe earth-shape geometry unrelated to canopy interference.

Explanation: A Geographic Coordinate System (such as WGS84) models the Earth as a 3D sphere or ellipsoid using angular measurement units (degrees latitude and longitude). A Projected Coordinate System (such as Map Grid of Australia / Universal Transverse Mercator) mathematically projects that 3D surface onto a flat 2D map using linear units (meters). Reversing the measurement units (meters for GCS and degrees for PCS) is incorrect. Associating GCS/PCS exclusively with vector/raster is false. Asserting that PCS preserves all geometric properties simultaneously contradicts Gauss's Theorema Egregium.

Explanation: Equal-Area (equivalent) projections preserve relative areal proportions across the map surface, ensuring that 1 square centimeter on any part of the map represents the exact same ground area. This is essential for comparing deforestation polygon areas across different continents. Conformal projections (like Mercator) distort area severely at high latitudes. Equidistant projections preserve scale only along specific lines.

Explanation: Stratified random sampling involves partitioning a target study population or landscape into distinct sub-groups (strata) based on known environmental characteristics (e.g., vegetation zones), and then taking random samples within each stratum. Simple random sampling samples the whole site without sub-grouping. Systematic sampling uses regular intervals (e.g., every 50 meters).