Digital Mapping Final Review

What is remote sensing?

The acquisition of information about an object or phenomenon without direct physical contact.

Name two examples of remote sensing technologies.

Aerial photographs and satellites.

What is a passive remote sensor?

A sensor that detects only received light, like photo

What does temporal resolution refer to?

How often a sensor can return to image the same spot on Earth.

What is spatial resolution?

The size of the smallest object a remote sensor can detect.

What is spectral resolution?

The bands and their wavelengths measured by the sensor along the electromagnetic spectrum.

What is radiometric resolution?

The ability of a sensor to detect differences in energy levels.

What is relief displacement in aerial imagery?

The effect where tall objects appear to lean outward from the photo's center.

What is an orthophoto?

An image corrected for camera perspective, ensuring consistent geographic scale.

What happens during transmission of energy?

Energy passes through a surface to interact with something else later.

What is absorption in remote sensing?

When energy is trapped and held by a surface.

What do remote sensing devices measure?

The reflectance of energy from a surface.

How do different materials reflect EMR?

Different materials reflect or absorb EMR differently, affecting how we see them.

What is true color imagery?

Imagery where input data matches the RGB bands we see.

What is the swath width of a Landsat satellite?

185 kilometers.

What is the advantage of using satellites for remote sensing?

They provide global coverage and can image larger areas than aircraft.

What does it mean if a sensor has a finer temporal resolution?

It returns to image the same spot more frequently.

What is the visible light spectrum?

The portion of the electromagnetic spectrum visible to the human eye, between 0.4 and 0.7 micrometers.

How do our eyes perceive color?

Through three types of cone cells sensitive to red, green, and blue light.

What is the role of sunlight in remote sensing?

Sunlight reflects off surfaces, which is then measured by sensors.

What is the significance of different wavelengths in remote sensing?

Different wavelengths can indicate different materials or conditions on the ground.

What is the primary challenge in showing unseen bands in remote sensing?

Representing bands like reflective infrared or thermal infrared that are not visible to the human eye.

Why can't a photo be used as a map?

Photos do not maintain a consistent scale across the image.

What is the effect of the sun's EMR on different materials?

Different materials reflect or absorb EMR differently, allowing identification in RS data.

What is the purpose of remote sensing?

To collect data about the Earth's surface from a distance.

What are the primary colors of light used in true color images?

Red, Green, Blue (RGB)

Which band represents red light in a true color image?

Band 3 (R)

Which band represents green light in a true color image?

Band 2 (G)

Which band represents blue light in a true color image?

Band 1 (B)

What does radiometric resolution refer to?

The amount of information perceived by a satellite's sensor.

What is the significance of a higher radiometric resolution?

More shades of grey are visible in the image.

What is ground truthing?

Verifying measurements at sample sites to ensure accurate image interpretation.

What does 'pattern' refer to in photo interpretation?

The arrangement of objects in an image.

What does 'site and association' mean in image interpretation?

Location of objects and their related attributes.

What does 'size' refer to in image interpretation?

Physical dimensions of objects.

What does 'shadow' indicate in an aerial image?

Information about height and depth.

What is 'tone' in image interpretation?

Grayscale levels or intensity of colors in an image.

What is Mean Sea Level (MSL)?

The average sea level used as a baseline for elevation.

What is absolute relief?

Actual numeric heights and their differences.

What is relative relief?

Height of one point in relation to another.

What are contour lines?

Connected lines of uniform elevation on a map.

What does a contour interval represent?

The vertical difference between contour lines.

What do closely spaced contour lines indicate?

A steep slope.

What do widely spaced contour lines indicate?

A gentle slope or flat land.

What is hypsometric tinting?

Elevation represented by color on a map.

What are isobaths?

Lines of equal water depth below MSL.

What is slope in terrain measurement?

Change in elevation defined as rise/run.

How is slope calculated as a percentage?

Divide rise by run and multiply by 100.

What are hachures?

Short lines indicating steepness or depressions on maps.

What is relief shading?

Shading used to highlight terrain features.

What is relief reversal?

When hills appear as valleys and vice versa in shading.

What does a DEM represent?

The bare

What is a DSM?

Digital Surface Model, capturing natural and built features.

What is a DTM?

Digital Terrain Model, which includes vector features like rivers and ridges.

What are the x, y, and z values in GIS?

x

What is cartographic partition?

Dividing territory into parts to create new political entities.

What historical treaties exemplify cartographic partition?

Treaty of Tordesillas (1494) and Treaty of Zaragoza (1529).

What does 'marking people as others' refer to in cartography?

Labeling groups to create divisions, often seen in colonial contexts.

What is gerrymandering?

Manipulating district boundaries to favor a political party.

What are the two methods of gerrymandering?

Cracking and Packing.

What is the consequence of gerrymandering?

Majority of votes may not equal majority of seats.

What is critical map reading?

Analyzing maps for biases and intentions.

What should you notice when reading a map critically?

What is included and omitted, symbols/colors, and creator's credibility.

What is the difference between a map's topic and proposition?

Topic is the subject; proposition is what the authors want you to believe.

What is a map projection?

A method to flatten the Earth's surface for a map.

What are ellipsoids in mapping?

Mathematically smooth 3D models of the Earth.

What is the purpose of coordinate systems in mapping?

To locate positions using latitude and longitude.

Why is understanding cultural context important in maps?

Maps reflect social and political biases.

What is the significance of visual hierarchy in maps?

It determines what the reader notices first.

How can maps persuade readers?

By what they include, visual elements, and storytelling.

What is the role of data in map creation?

Maps should be based on observable and replicable data.

What is the impact of urban planning on cartography?

It shapes how land is divided and utilized.

What does 'redlining' refer to?

Discriminatory practice preventing certain groups from home ownership.

What is the importance of analyzing map creators?

To assess credibility and potential biases.

What is the relationship between maps and power dynamics?

Maps can reflect and reinforce social hierarchies.

What is a datum?

A reference surface or model of Earth used for plotting locations.

What is NAD27?

North American Datum of 1927, centered at Meades Ranch, Kansas.

What is NAD83?

North American Datum of 1983, an updated reference frame.

What is WGS84?

World Geodetic System of 1984, a global datum.

What is NAVD88?

North American Vertical Datum of 1988, used for elevation measurements.

What is the NSRS 2022?

National Spatial Reference System 2022, modernizing outdated datums.

What is a datum transformation?

A computational process to convert measurements between different datums.

What is a Geographic Coordinate System (GCS)?

A system using latitudes and longitudes to represent locations.

How are GCS measurements expressed?

In degrees, minutes, and seconds (DMS) or decimal degrees (DD).

What do Projected Coordinate Systems (PCS) represent?

The Earth's surface on a flat map.

Why is it called a 'Projection'?

It simulates shining light through Earth onto a flat surface.

What are standard points/lines in projections?

Locations where the projected surface meets the Earth, minimizing distortion.

What is area distortion?

Alteration of the size of features on a map compared to their true size.

What is shape distortion?

Alteration of the true shapes of features on a map.

What is direction distortion?

Inaccuracies in angles or bearings between points on a map.

What is distance distortion?

Inaccurate representation of distances between points on a map.

What is Tissot's Indicatrix?

A tool illustrating how a projection distorts the world.

What is an Azimuthal projection?

A flat plane projection that best preserves direction at a standard point.

What is a Conic projection?

A projection created by wrapping a cone around the Earth's surface.

What is a Cylindrical projection?

A projection created by wrapping a cylinder around the Earth.

What is the Mercator Projection?

A cylindrical projection preserving angles and direction.

What is UTM?

Universal Transverse Mercator, dividing the world into zones for coordinates.

How does UTM measure coordinates?

Using easting and northing in meters from the Equator.

What is false northing in UTM?

Adding 10,000,000 meters to avoid negative values in the southern hemisphere.

What is SPCS?

State Plane Coordinate System, a grid