Lecture on Remote Sensing and GPS Technology

Flashcards summarizing key concepts from the lecture on remote sensing and GPS technology.

What does the legend 'R: Red, G: Green, B: Blue' indicate when seen on an image?

A true color composite.

What are the devices called that generate separate signals for the primary colors in monitors, projectors, and TVs?

Color guns.

What is the only form of energy transfer that can occur in a vacuum?

Radiation.

When light travels, it behaves like a , but when it interacts with matter, it behaves like a .

wave, particle.

What is defined as the distance between consecutive maximum or minimum of a roughly periodic pattern?

Wavelength.

Is the speed of light generalized to 3 x 10^8 m/s?

True.

According to the wave model, do wavelengths with higher frequencies tend to be shorter than those with lower frequencies?

True.

In quantum theory, the lower the energy content (Q), the _ the frequency.

lower.

In what portion does the sun produce a continuous spectrum of electromagnetic radiation, peaking in the ____ portion?

visible.

List the wavelengths in ascending order, shortest to longest.

UV, blue, green, red, near infrared.

What is the longest visible wavelength?

Red.

What is the wavelength range of the shortest infrared SWIR region?

1.3 to 3.0 micrometers (µm).

What is remote sensing?

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

Can sensors detect light outside the visible portion of the electromagnetic spectrum while humans cannot?

False.

What does passive remote sensing record?

Energy.

What phenomenon primarily affects blue wavelengths and contributes to blue skies?

Rayleigh scattering.

What type of scattering occurs when radiation interacts with atmospheric particles whose diameter is approximately equal to the wavelength?

Mie scattering.

Why are clouds white?

Due to non-selective scattering.

What are portions of the electromagnetic spectrum that effectively transmit energy called?

Atmospheric windows.

What is the term for the process whereby radiation bounces off an object?

Reflectance.

What is a Lambertian surface?

A surface that reflects energy equally in all directions.

What pigment is responsible for the reflectance of healthy green plants in the green portion of the spectrum?

Chlorophyll pigments.

What term describes the transition between strong absorption in red and significantly high reflectance in NIR?

Red edge.

How is a vegetation index calculated in a satellite image?

On a pixel-by-pixel basis.

Which region of the electromagnetic spectrum do many active remote sensing systems operate in?

Microwave region.

What wavelengths do LiDAR systems use for topographic mapping?

Near Infrared (NIR).

What does a LiDAR system measure?

Distance.

What is the formula LiDAR uses to measure the range to a target?

Range = (t * c) / 2.

What do we need to create a Canopy Height Model?

A Digital Surface Model and a Digital Terrain Model.

What method is used to determine position based on intersecting circles or spheres?

Trilateration.

How many satellites must a GPS receiver detect at minimum to calculate an accurate location?

4.

What principle do GPS receivers use to determine their position on Earth?

By receiving signals from at least four GPS satellites and calculating travel time.

Why is a fourth satellite required in GPS trilateration?

To resolve the receiver's clock error by introducing a fourth dimension, time.

Who initiated the OpenStreetMap project?

Steve Coast.

What does geotagging from social media provide access to?

Valuable location-based data related to people's activities, interests, and behaviors.

What is the concept of Volunteered Geographic Information in Neogeography?

The engagement of private citizens in creating geographic information.

Who is the originator of the Volunteered Geographic Information concept?

Dr. Mike Goodchild from UC Santa Barbara.