2 Maps, Scale, and Map Projections Free Online FlashCards

What does a reference map show?

Reference maps show where features such as roads, rivers, place names, and boundaries are located.

What does a map legend explain?

A legend, or key, explains the map’s symbols, colors, and line styles.

How does a representative fraction express map scale?

A representative fraction gives the map-to-ground distance ratio using the same units. For example, on a $1:50{,}000$ map, $1$ unit on the map represents $50{,}000$ units on the ground.

Why does every flat world map distort some spatial property?

A map projection mathematically represents locations on Earth’s curved surface on a flat map. Flattening the surface necessarily distorts at least one property: area, shape, distance, or direction.

What should guide the choice of a map projection?

Choose a projection based on the map’s purpose, geographic extent, and location. For example, equal-area projections suit regional area comparisons, while conformal projections may suit navigation or detailed local mapping.

What is the purpose of a thematic map?

A thematic map emphasizes a particular subject or spatial pattern, such as population density, rainfall, or land use.

What information does a topographic map commonly show?

A topographic map represents landforms and elevation, commonly using contour lines, and may also show roads and water.

What does map orientation indicate?

Orientation indicates direction, often with a north arrow or compass rose. True north, grid north, and magnetic north are not always identical.

How do large-scale and small-scale maps differ?

A large-scale map has a smaller representative-fraction denominator and usually shows a smaller area in greater detail. A small-scale map has a larger denominator and generally shows a larger area in less detail.

Why is a graphic scale useful when a printed map is resized?

A graphic scale is a marked bar that represents ground distance. If a printed map is resized, the bar resizes with it, unlike a printed ratio or verbal scale.

What trade-off is characteristic of conformal projections?

Conformal projections preserve local angles and the shapes of small features, but can distort area. Mercator is useful for some navigation tasks, yet greatly enlarges high-latitude areas.

When is an equal-area projection useful?

Equal-area projections preserve relative area, making them useful for comparing quantities across regions. They may distort shapes, especially over large areas.