GIS Map Projections and Datums 5

Question 1

A Stereographic projection is classified as:

Accepted Answer

Azimuthal and conformal

Answer

The Stereographic projection is azimuthal (projected onto a plane) and conformal (preserving local shapes and angles), commonly used for polar regions.

Question 2

When a GIS project requires area measurements to be accurate across a large country, the best projection choice is:

Accepted Answer

Equal-area (e.g., Albers Equal-Area)

Answer

Equal-area projections preserve relative areas across the map, making them the correct choice for any analysis involving area calculations.

Question 3

The difference between NAD83 (2011) and NAD83 (HARN) realizations of the same datum is due to:

Accepted Answer

Updated survey network adjustments providing more accurate station coordinates

Answer

HARN (High Accuracy Reference Network) was a 1990s re-observation of control stations; NAD83(2011) uses GPS-derived adjustments, both improving on the original NAD83 realization.

Question 4

In a Lambert Conformal Conic projection, which areas experience the least scale distortion?

Accepted Answer

Along the standard parallels

Answer

Scale distortion is zero at the one or two standard parallels where the cone intersects the ellipsoid, increasing with distance from those lines.

Question 5

The Gnomonic projection has the unique property that:

Accepted Answer

Great circles appear as straight lines

Answer

On the Gnomonic projection, any straight line drawn on the map is a great circle, making it useful for planning the shortest flight paths.

GIS - Geographic Information System Practice Test

GIS - Geographic Information System Practice Test

GIS Map Projections and Datums 5