GPS/GIS Test 1

A. False

All trained professionals should recognize all features of an aerial photograph identically. Ture or false?? A. False B. True

B. datum

An estimate of the earth's surface based on an ellipsoid provides a determination of the elevation of every point on the earth's surface, including sea level is often called what? A. coordinate system B. datum C. geographic coordinate D. projection

The interpreter's skills can be enhanced by practice.

An increase in the skills of the photo interpreter will reduce the dependence on subjectivity. How can the interpreter's skills be enhanced?

B. False

All maps and map Projections maintain a constant correct scale throughout a printed image of a map. A. True B. False

B. 60 Nautical Miles

1 degree is equal to...? A. 125 Nautical Miles B. 60 Nautical Miles C. 75 Nautical Miles D. 50 Nautical Miles

The equatorial diameter is greater.

Based on the GRS80 Ellipsoid, is the polar diameter or equatorial diameter greater?

GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to the earth, GPS receivers take the information to compare the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is. Now, with distance measurements from a few more satellites, the receiver can determine the user's position and display it on the unit's electronic map.

Basically, how does GPS work to determine a position?

The space segment of the system consists of GPS satellites. The control segment consists of a system of tracking stations located around the world. The user segment consists of the GPS receivers and the user community.

Briefly describe each GPS segment.

GPS is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense.

Briefly state what GPS is.

Yes, shadows can be helpful when interpreting objects in an aerial photo. Shadows give clues to the profile shape and relative sizes of landscape features. They can obscure detail in other landscape features.

Can shadows be helpful when interpreting objects on an aerial photo? Explain the ways in which shadows can help with photo interpretation.

World Geodetic System (1972)

Compare the values given in the reference ellipsoids table and determine for which ellipsoid a value appears to be incorrect.

The geometry (more or less spread) of the satellite constellation can affect the accuracy of the GPS positions. DOP is an indicator of the spread.

Define DOP (Dilution of Precision)?

A datum is defined as any numerical data set of earth references that serve as a basis for other references.

Define datum.

Map projection is the transformation of an essentially spherical surface to a plane surface.

Define map projection.

Photogrammetry is defined as the technique of obtaining reliable measurements of objects from their photographic images.

Define photogrammetry.

The Greenwich Meridian passes through the Royal Greenwich Observatory in London. Null Island (0 degrees North, 0 degrees East).

Describe the Greenwich Meridian. At what point on earth would the position be 0 degrees latitude and 0 degrees longitude?

Good satellite geometry is if the satellites are spread apart, while poor satellite geometry is if the satellites are physically close together.

Describe the characteristics of good and poor satellite geometry?

An imaginary great circle around the earth's surface, everywhere equally distant from the North Pole and the South Pole that divides the earth into the Northern Hemisphere and the Southern Hemisphere.

Describe the earth's equator.

The GPS Nominal Constellation has 24 satellites in 6 orbital places, 4 satellites in each plane, and 20,200 km Altitudes, 55 Degree Inclination.

Describe the nominal GPS constellation including the number of satellites, orbital planes, altitude of satellites, inclination, etc.

Latitude lines are parallels, run east-west, indicate position by north-south, and do not converge. Longitude lines are meridians, run north-south, indicate position east-west, and do converge.

Discuss lines of latitude and line of longitude with respect to the following: - Are they meridians or parallels? - Which way do they run? - In which direction do they indicate position? - Do they converge?

GPS receivers are accurate to within 15 meters on average. Newer GPS receivers equipped with WAAS (Wide Area Augmentation System) capability can improve accuracy to less than three meters on average. Users can also get better accuracy with DIfferential GPS (DGPS), which corrects GPS signals to withing an average of three to five meters.

Discuss the accuracy of GPS units.

Selective keys are usually made up of typical illustrations and descriptions of objects in a given category. They are organized for comparative use. Elimination keys require the user to follow a step-by-step procedure, working from the general to the specific.

Discuss/explain the two categories of photo interpretation keys.

The process of gathering information from afar, such as viewing the Earth from space. Also regarded as 'reconnaissance from a distance'.

For the purpose of this class and simply stated what is the definition of 'Remote Sensing'?

NAD83 provides a better worldwide fit.

Does NAD27 or NAD83 provide a better worldwide fit?

Mapping larger areas.

Does the problem of distortion errors become more of an issue when mapping larger or smaller areas?

Photo Interpretation is both reading the lines and reading between the lines, while photo reading is concerned with only identifications.

Explain photo interpretation as compared to photo reading indicating the significant difference between them.

Photo interpretation is examining photographic images for the purpose of identifying objects and judging their significance. Photogrammetry is obtaining reliable measurements of objects from their photographic images.

Explain the difference between photo interpretation and photogrammetry.

Water appears as shadows of blue, varying from nearly black (in clean water) to pale blue (increasing amount of sediment, and shallow water is determined by material present at the bottom. If it is very shallow it appears as white aerial photographs. In black and white aerial photographs, they use various shades of gray to tell the type of body of water.

Explain the tonal/color characteristics of a body of water on color and b/w aerial photographs. What causes the difference in tone/colors?

Global Positioning System

GPS is an acronym for what technology?

The effect of GPS signal errors can be reduced by differential correction.

How can the effect of GPS signal errors be reduced?

The interpreter's job can often be made easier when comparative, or sequential, coverage is available. This refers to two or more sets of photographs of the same area taken at different times.

How can the interpreter's job often be made easier?

He authorized the use of GPS by civilian commercial airlines in an attempt to improve navigation and safety for air travel. This became the first step towards authorized civilian usage.

How did President Ronald Reagan promote the development of GPS?

GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to Earth.

How does GPS work?

A datum is established using a reference ellipsoid.

How is a datum established?

By meridians and parallels.

How is a position on the earth measured?

Pattern deals with the spatial arrangement of objects on a landscape, whereas texture deals with changes in tone or the arrangement of tone on a landscape.

How is pattern different than texture? Same as slide #16.

D. 12 hours

How long does it take one satellite to orbit the earth? A. 10 hours B. 24 hours C. 6 hours D. 12 hours

B. 91.83

How many acres are in one square inch on a map/photo with a scale of 1:24,000? A. 160.00 B. 91.83 C. 99.64 D. 40

B. 180 degrees

How many degrees does the International Dateline mark? A. 1 years rotation B. 180 degrees C. 90 degrees D. 360 degrees

Four or more satellites.

How many satellites need to be tracked to determine 3-D positioning?

The GPS unit normally indicates the user's position with a blue dot.

How will the GPS unit normally indicate the user's position?

One feature I see is a field in each picture.

Shape is an important principle used to identify objects in an aerial photograph. Identify at least one feature on each of the 4 photos on slide #6... look closely.

Transverse Mercator Projection: Zones 6 degrees Longitude World-Wide, Northing Origin (0 meters - Northern Hemisphere) at the equator, Easting Origin (500,000 meters) at Central Meridian of each zone. NAD27 and NAD83 are both defined in meters, and NAD27 to NAD83 shift = 200-225 meters for the U.S.

Identify the basic characteristics of Universal Transverse Mercator.

D. Lines of Position

In navigation, what are the two lines called? A. Latitude and Longitude Lines B. Coordinate System C. Parallels D. Lines of Position

During winter because the light is good, winter also creates crystalline skies and unmatched clarity in photos, and with decreasing temperatures, the image noise decreases.

Normally, during what part of the year would it be best to take aerial photos? Explain your answer.

GPS technology is used in Forestry classes liked Applications of GPS/GIS in Forestry.

In which Forestry class will GPS technology be used?

- Acreage Determination - Aid to Navigation - Site Mapping - Location of pertinent geographical features or phenomenon

Indicate some forestry applications of GPS data collection and processing.

Equatorial Diameter is the major axis, and Polar Diameter is the minor axis.

Indicate the polar diameter and equatorial diameter in terms of axis.

Position in geodetic coordinates (LLA) with latitude and longitude given in degrees, minutes, and seconds.

Indicate the way in which the GPS unit (to be used in this class) can indicate your position on earth.

It is better to have lower DOP.

Is it better to have a higher or lower DOP?

Lower DOP values are better.

Is it better to have higher or lower DOP values?

Latitude because they do not converge at the poles.

Is it better to use latitude or longitude to determine distance? Why?

It means that aerial photo interpretation is two different things. It's a science, but it's also commonly referred to as an art.

It is stated that aerial photo interpretation often involves a considerable amount of subjective judgment. What does this mean? Use your own words as much as possible.

C. State Plane

Large states often require several zones when using this projection for the U.S. It can be based on either the Lambert Conformal Conic or Transverse Mercator Projection, depending on the orientation of each state. A. WGS84 B. Universal Transverse Mercator C. State Plane D. NAD83

Shape: The element of shape describes the external form or configuration of an object. Cultural objects tend to have geographical shapes and distinct boundaries, whereas natural features tend toward irregular shapes with irregular boundaries. Size: In two-dimensional space, size is a measure of the surface dimensions of an object. Relative size comparisons can be an important aid in identifying features. Pattern: Pattern refers to the overall spatial form of related features. The repetition of certain forms is characteristic of many cultural objects and some natural features. Shadow: Shadows cat by oblique illumination are important in photo interpretation because their shapes provide profile views of certain features that can facilitate their identification. Tone or Color: Tone or color relates to the reflective characteristics of objects within the photographic spectrum. Texture: The visual impression coarseness (roughness) or smoothness caused by the variability or uniformity of image tone or color is known as texture. Association: Certain objects are "genetically" linked to other objects so identifying one tends to indicate or confirm the other. The association is one of the most helpful clues for identifying cultural features that compromise aggregate components. Site: The location of an object in its environment is called the site factor and is important for recognizing many cultural and natural features.

List and briefly define each of the recognition elements.

Tangency at the pole is a polar aspect; at mid-latitude, an oblique aspect; and at the equator, an equatorial aspect.

List and describe the three aspects of projection.

1. Pseudorandom Code is simply an I.D. code that identifies which satellite is transmitting the information. 2. Ephemeris Data is constantly transmitted by each satellite and contains important information about the status of the satellite, current date, and time. Essential for determining a position. 3. Almanac Data tells the GPS receiver where each GPS satellite should be at any time throughout the day.

List and describe the three different bits of information that a GPS signal contains.

1. Space Segment: consists of GPS satellites, and space vehicles send radio signals from space. 2. Control Segment: consists of a system of tracking stations located around the world. 3. User Segment: consists of the GPS receivers and the user community.

List and describe the three segments that makeup GPS.

Location, navigation, tracking, and mapping.

List some general uses of GPS technology.

Monitoring the changing water levels of lakes and reservoirs, assessing crop diseases, locating new highway routes, identifying and assessing land-use changes, and mapping archaeological sites.

List some of the uses of photo interpretation.

1. Atmospheric Conditions a. Ionosphere - a layer of the atmosphere 80-120 miles above the earth. - Factors include elevation angle, time of day, season, solar activity, etc. b. Troposphere - a layer of the atmosphere that extends to about 80 miles above the earth. - Factors include weather (temperature, humidity, pressure, etc) and are strongly linked to elevation angle. 2. Position of the Satellite (Elevation Angle) - Factors include more noise to its signal. 3. Multipath Error - Factors include obstructions and reflective surfaces (roofs, glass, metal, and water). 4. Ephemeris Error - Orbital information broadcast by the satellite contains errors. - The receiver does not know the exact position of the satellite. 5. Satellite Clock Drift - Very small errors in the satellite clock time may exist. - Causes errors in the psudorange or carrier phase measurements. 6. Selective Availability (SA)

List the possible sources of GPS errors and factors that can affect accuracy.

-Photographic Imagery: The oldest and perhaps the best-known form of remote sensing. 1. Black and White Photography: Panchromatic film 2. Color Photography 3. Color Infrared Photography: Vegetation studies 4. Black and White Infrared Photography -Non-photographic Imagery: Gather information using the non-visible portions of the electromagnetic spectrum. 1. Radar: Radio Detecting And Ranging; the sensor generates its own energy with which to scan the environment. 2. Thermal Infrared: Thermography 3. Ultraviolet Sensing: Collects energy in short wavelengths that are outside the visible light band of the electromagnetic spectrum. -Satellite Imagery 1. Landsat (Land Satellite) - Multispectral Scanning System (MSS) and Thematic Mapping (TM). 2. SPOT (Satellite Pour L'Observation De La Terre) - High Resolution Visible (HRV) imaging system. 3. GOES (Geostationary Operations Earth Satellite) -Satellite Positioning: GPS

List the various forms of remote sensing and the categories within each form.

A. Revolution

Motion of the earth in its yearly orbit around the sun... A. Revolution B. Rotation

Shape, Size, Pattern, Shadow, Tone or Color, Texture, Association, and Site.

Name the eight basic principles used in photo interpretation.

Areas with increased moisture will be darker because, moisture absorbs light making i darker.

On B/W IR photographs, will areas with increased moisture be darker or lighter than the surrounding area? Why?

Conifer trees will be darker.

On black and white infrared (B/W IR) photos, will hardwoods or conifers appear darker?

Ephemeris Errors

Orbital errors are also known as what type of errors?

GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to Earth. GPS receivers take this information and use trilateration to calculate the user's exact location.

Provide a simple explanation of how GPS works.

B. True

Shadows captured on aerial photographs are often useful in identifying what an object actually is. True or false?? A. False B. True

The technique of obtaining information about objects through the analysis of data collected by special instruments that are not in physical contact with the objects of investigation.

Remote Sensing can also be defined as what?

This question pertains to the patterned picture, which looks to be a subdivision. It's asking which house is yours.

Slide #18: Which one is yours?

It looks like a pattern of hills.

Slide #19: What"s going on here?

Fields

Slide #29: What is this?

Power plant, and it is made by humans.

Slide #30: What is this? Made by humans?

Over the years, wind the wind picked up the sand making sand dunes.

Slide #31: What happened here?

Bodies of water.

Slide #32: What are these?

Because moisture is good there. The vegetation type is grass.

Slide #33: Why are the oak trees dense here? What vegetation type is this?

In the afternoon.

Slide #34: Assuming North is the top of the photo, and South is the bottom, what time of day was this photo taken?

Because there is no current.

Slide #35:Why is there a big swath in this stand?

Crater; the red "stuff" is either red dirt or clay.

Slide #36: What is this? What is the red "stuff"?

He's telling the time with his shadow.

Slide #37: What is this guy doing?

A floodplain.

Slide #39: What is this man-made landscape feature?

Pines and oaks because of their shape and colors.

Slide #40: What tree species are here? How do you know?

Trees

Slide #41: What landscape features are these?

Plane of water.

Slide #42: What is this landscape feature?

Sinkholes.

Slide #43: What are these round features?

Live vegetation.

Slide #44: What are these red areas?

Animals, like cows.

Slide #45: What are these dots?

Water is going off a cliff, making it a waterfall.

Slide #46: What's going on here?

Red trees are live vegetation, and yellow trees are dead vegetation.

Slide #47: Why are these trees red? Why are some of them yellow?

I see trees, water, roads, bridges, sport fields, buildings like houses, and parking lots.

Slide #48: What are some of the items that you see in this photo? List as many as you can.

An oblate spheroid is a solid obtained by rotating an ellipse on (average) its shorter (minor) axis.

Some references describe the earth as an oblate spheroid. What is an oblate spheroid?

B. Rotation

Spinning of the earth around its own axis each day... A. Revolution B. Rotation

- LLA- Latitude, Longitude, and Altitude - UTM - Universal Transverse Mercator - SPC - State Plane Coordinates

The GPS unit can be set up to use any of which coordinate systems?

Satellite Navigation System

The Global Positioning System is primarily what type of system.

When cartographers specify geometric coordinate into geographic reference points, or when other source documents (aerial photos, remotely sensed images) are referenced to a common coordinate system, it is called georeferencing.

What is georeferencing?

Satellite geometry is the relative position of the satellites at any given time.

What is satellite geometry?

World War II because countless military decisions were based on intelligence reports derived from aerial reconnaissance.

The development of photo interpretation skills was primarily the result of what major historical occurrence? Explain.

A. 360 degrees

The earth rotates how far on its axis in 24 hours? A. 360 degrees B. The earth is flat it does not rotate C. 90 degrees D. 180 degrees

B. 24

The nominal GPS Operational Constellation consists of how many satellites? A. 34 B. 24 C. 12 D. 32

B. The Coriolis Effect

The rotation of the earth affects cyclones by means of an apparent process called... A. Deflection B. The Coriolis Effect C. Trade Winds D. The Butterfly Effect

The result of changes in tone, or the arrangement of tone on a landscape.

What is texture?

The opposite of geographic north, the geographic south.

What is the antipodal point?

Geoid; the earth is flattened at the poles and extended at the equator.

Today, what term is commonly used to describe the shape of the earth? Briefly discuss the earth's shape.

World Geodetic System 1984 (WGS-84)

Upon which datum is GPS based?

Differential correction is the process of using position data (control Data) collected by a receiver at or from a precisely known location to correct data collected by a rover GPS receiver.

What is differential correction?

Map projection

WHat is the system used to portray a part of the round Earth on a flat surface?

Navigation Satellite System

What GPS unit is used in the ICC Forestry classes?

Human forms of remote sensing are sight, smell, and hearing.

What are examples of human forms of remote sensing?

-Acreage Determination -Aid to Navigation -Site Mapping -Location of pertinent geographical features or phenomenon

What are some basic forestry applications of GPS?

GPS operates in all weather conditions, is available 24 hours/day, and is available anywhere on the planet. There are also no subscription fees or setup charges to use GPS.

What are some of the advantages of GPS?

Photo interpretation techniques are used on such diverse projects as monitoring the changing water levels of lakes and reservoirs, assessing crop diseases, locating new highway routes, identifying and assessing land-use changes, and mapping archaeological sites.

What are some of the diverse projects on which photo interpretation techniques are used today? Indicate how you might be using aerial photo interpretation in your Forestry Technology courses.

Some land-based applications of GPS are maps of property lines, county roads, highways, etc.

What are some of the land-based applications of GPS?

- Ionosphere and Troposphere Delays - Signal Multipath - Receiver Clock Errors - Orbital Errors - Number of Satellites Visible - Satellite Geometry/Shading - Intentional Degradation of the Satellite Signal- Selective Availability

What are some sources of error that will have an effect on GPS accuracy?

PDOP= Position Dilution of Precision (3-D) HDOP= Horizontal Dilution of Precision (Latitude, Longitude) VDOP= Vertical Dilution of Precision (Height) TDOP= Time Dilution of Precision (Time)

What are the components of GDOP?

Identifying both natural and man-made features on the earth's surface and judging their significance.

What are the concerns when interpreting aerial photographs?

The North and South Poles and the equator.

What are the most important elements of the earth's coordinate geometry?

The requirements are long hours of practice, ground visitations, and a background in earth sciences and biological sciences.

What are the requirements to become skilled in Photo Interpretation?

Space Segment, Control Segment, and User Segment.

What are the three (3) segments of GPS?

Plane, cylinder, and cone.

What are the three basic forms of developable surfaces?

Tearing, shearing, or compression.

What are the three causes of map distortion error?

Data Collection and Data Analysis

What are the two major components of remote sensing?

1. Real-Time Differential Correction: a radio signal containing the differential corrections is transmitted from a base station to a receiver built-in or connected to the GPS unit - the radio signal is used to correct the GPS positions in the field in real-time. 2. Post-Processing Differential Correction: corrects much of the error in GPS data from 15-meter errors.

What are the types of differential correction?

A. Photo Interpretation

What can be defined as the process of identifying objects or conditions in aerial photographs and determining their meaning or significance? A. Photo Interpretation B. Imagery Interpretation C. Imagery Interpretation D. Photo Analysis

Latitude, longitude, and altitude.

What data would a 3-D position provide?

A. Scale

What defines the relationship between a linear distance on a vertical photograph and the corresponding actual distance on the ground? A. Scale B. Relationship Factor C. Focal Length D. Photogrammetry

The determination of the type of key and method of presentation to be used depends on (1) the number of objects or conditions to be recognized and (2) the variability normally encountered within each classification.

What determines the type of key and method of presentation to be used?

Geodetic datums define the size and shape of the earth and the origin and orientation of the coordinate systems used to map the earth.

What do geodetic datum define?

The spherical elements, the meridians and parallels, are called projection graticule.

What does the term graticule mean?

Selective Availability is an intentional degradation of the signal once imposed by the U.S. Department of Defense. It was intended to prevent military adversaries from using highly accurate GPS signal.

What is 'Selective Availability'?

Trilateration is the use of distances for determining the unknown position coordinates of a print of interest, often around Earth.

What is 'Trilateration'?

A grid system of intersecting perpendicular lines on a plane containing two principal axes called the x-and-y-axes. It compares to plane coordinate geometry by; (1) latitude is measured by counting angular degrees along a meridian and (2) longitude is measured by counting degrees along a parallel.

What is Cartesian coordinate geometry? How does it compare to plane coordinate geometry?

Dilution of Precision (DOP) is used to specify the error propagation as a mathematical effect of navigation satellite geometry on positional measurement precision. The geometry (more or less spread) of the satellite constellation can affect the accuracy of the GPS positions. DOP is an indicator of the spread.

What is DOP and how does it relate to satellite geometry?

GDOP is Geometric Dilution of Precision. GDOP is computed from the geometric relationships between the receiver position and the positions of the satellites that the receiver is tracking.

What is GDOP? Provide a brief description.

GPS is a satellite-based navigation system comprising 24 satellites placed into orbit by the U.S. Department of Defense (DOD). GPS stands for the Global Positioning System.

What is GPS? Describe the Global Positioning System.

Geodesy is the science of earth measurement.

What is Geodesy?

A specialized electronic device equipped with the ability to determine the user's position on earth by receiving and processing signals from orbiting satellites.

What is a GPS receiver?

D. Global Positioning System

What is a U.S. - owned utility that provides users with positioning, navigation, and timing (PNT) services? A. Geographic Information System B. Geographic Position Sensing C. Remote Sensing D. Global Positioning System

A base station is a GPS receiver logging position data at a known location.

What is a base station?

A geographic grid is a spherical coordinate system (parallels and meridians) used for the determination of location on the earth's surface.

What is a geographic grid?

Pattern is the spatial arrangement of objects on a landscape. Man-made objects have well-defined geometric patterns made up of smooth lines and curves, whereas naturally occurring objects are not as uniform.

What is a pattern and how would patterns of man-made objects normally be different from the patterns exhibited by naturally occurring objects?

A set of guidelines used to assist interpreters in rapidly identifying photographic features; selective keys and elimination keys.

What is a photo interpretation key? What are the two general classes into which they can be grouped?

A. Photo-Interpretation Key

What is a set of guidelines used to assist interpreters in rapidly identifying photographic features? A. Photo-Interpretation Key B. Imagery Element Key C. Imagery-Interpretation Key D. Recognition Element Key

D. Dot Grid

What is a sheet of transparent material imprinted with dots arranged in a regular grid or in a spatially stratified random pattern? These can be purchased from forestry suppliers or developed from graphics software and printed onto transparency material. A. Grid Square B. Dot Transect C. Grid Dot D. Dot Grid

To be able to recognize landscape features on an aerial photograph and make inferences about the environment.

What is an objective of Photo Interpretation?

B. Geographical North

What is another name for the north pole? A. Antipodal Point B. Geographical North C. Bermuda Triangle D. Geographical South

B. Remote sensing

What is defined as the technique of obtaining information about objects through the analysis of data collected by special instruments that are not in physical contact with the objects of investigation? A. Geographic Sensing B. Remote Sensing C. Geographic Positioning D. Remote Positioning

C. Photogrammetry

What is defined as the technique of obtaining reliable measurements of objects from their photographic images? A. Scale Relationships B. Scale Recognition C. Photogrammetry D. Photo Interpretation

GPS units that we would use are satellite-based radio navigation systems and the control station GPS unit is a global network of ground facilities.

What is the basic difference between the GPS unit that we would use and a control station GPS unit?

The position of the plane that produces the simplest graticule.

What is the basis for the 'normal aspect'?

In each case these projections in effect project as rectangular grids, with negligible areal or distance distortion. Because the grids are conformal, no angular distortion is present. Each state has defined its large-scale coordinate system and its starting point. In order to reduce distortion many states have corrections built in that may run N-S or E-W depending on state orientation. The central meridian of a state's grid has an assigned 'easting' value (the x value( and each grid begins with a specified false 'northing' (the y value). In those states with two or more grids, each zone has its central meridian.

What is the characteristics of distortion with these projections? How have the states reduced distortion that may exist?

Photo interpretation is defined as the process of identifying objects or conditions in aerial photographs and determining their meaning or significance.

What is the definition of Photo Interpretation?

Relative size is the size of an unknown object in relation to the size of a known object. Absolute size is the actual size of a landscape feature, which requires an understanding of the photo scale.

What is the difference in relative and absolute size?

Ellipsoid

What is the earth's flattened shape best described as what?

Within 15 meters on average.

What is the expected accuracy of today's GPS receivers?

Systems of parallels (lines of latitude) and meridians (lines of longitude).

What is the geographic grid of the earth?

D. Equator of a planet

What is the great circle who planes pass through the center of the body? A. Earths Equator B. Meridians C. Longitude and Latitude D. Equator of a planet

To determine a user's position and place it on an electronic map.

What is the job of the GPS receiver?

10 years

What is the life expectancy of each satellite?

With a system of reference lines called parallels of latitude and meridians of longitude.

What is the most convenient way to identify points on the surface of the earth?

B. Ephemeris

What is the name of the data that is constantly transmitted by each satellite, contains important information about the status of the satellite (healthy or unhealthy), current date and time? This part of the signal is essential for determining a position. A. Selective B. Ephemeris C. Almanac D. Orthogonal

Axis of rotation

What is the name of the imaginary axis about which the earth rotates?

B. Geographic Coordinate System

What is the name of the system of latitude and longitude? A. Universal Transverse Mercator B. Geographic Coordinate System C. Lambert Conformal D. State Plane

Azimuthal family's normal aspect is the polar aspect, Cylindrical family's normal aspect is the equatorial aspect, and Conic family's normal aspect is the oblique aspect.

What is the normal aspect of each of the projection families?

50 watts or less

What is the power of a satellite transmitter?

The line of longitude marks 0 degrees and passes through Greenwich, England. It divides the earth into the western hemisphere and the eastern hemisphere.

What is the prime meridian? What does it divide the earth into?

The principle behind the SPCS is that if the area being mapped is small enough, essentially no distortion (due to the earth's curvature) exists.

What is the principle behind the state plane coordinate system?

The projection aspect refers to the position of the plane of projection relative to the ordinary position of the geographic grid on the earth.

What is the projection aspect?

The angular measurement, used to specify a location on the earth, is based on the sexagesimal scale, with sixty as its base.

What is the sexagesimal system?

200-225 meters

What is the shift between NAD27 and NAD83?

A. Map Projection

What is the system used to portray a part of the round Earth on a flat surface? A. Map Projection B. Map Transformation C. Graticule Transformation D. Azimuthal Projection

C. Texture

What is the visual impression of coarseness or smoothness caused by the variability or uniformity of image tone or color? A. Appearance B. Consistency C. Texture D. Surface

Lambert conformal conic for states with long east-west directions, Transverse Mercator for states with long north-south directions, and Oblique Mercator for positions of Alaska.

What map projections did the USGS use to map the states?

Ephemeris Data

What part of the GPS signal is essential for determining your position?

A. Prime Meridian

What passes through Greenwich, England? A. Prime Meridian B. Equator C. Base Line D. Base Meridian

Tone (and color) varies both within and between photographs, between seasons of the year, and with the position of the sun in relation to the camera.

Why can tone/color vary on different photos of the same area?

Chlorophyll is sensitive to near-infrared light, so a high percentage of near-infrared light is reflected off the leaves in healthy plants.

Why do the healthy trees appear to be red?

Because of recent advances in satellite geodesy with higher degrees of accuracy, and because many surveying errors have built-up since the last datum was adopted (NAD27), a new datum was selected in 1983.

Why is NAD83 better than NAD27?

- Azimuthal Family- The spherical grid is projected onto a plane. This plane can be tangential to the sphere at a point (simple form) or pass through the sphere making it tangent along a small circle (secant form). The normal aspect for the azimuthal family is the polar position when the plane is tangent to one of the poles. - Cylindrical Family- Common forms that are frequently seen in atlases and other maps portraying the whole world. They are developed by wrapping a flat plane (sheet) into a cylinder and making it tangent along a line on the sphere. Points, lines, and features are transferred to this cylinder, which is then unrolled into a flat map. The normal spect for these projections is the equatorial aspect, with the equator as the standard line. - Conic Family- Constructed by transferring points from the sphere grid to a cone enveloped around the sphere. This cone is unrolled into a flat plane. In the simple conic projection (normal aspect), the cone is tangent along a chosen parallel forming a circle. The normal spect for these projections is the oblique aspect which means tangency at any point on the globe other than the poles or the equator.

What projection families do these developable surfaces provide? Describe the surface orientation (relative to the sphere) of the developable surfaces and the map projection process for each of the projection families.

Geodetic Reference System (GRS80). This datum was selected because of recent advances in satellite geodesy with higher degrees of accuracy, and because many surveying errors have built-up since the last datum was adopted.

What reference ellipsoid does NAD83 use? Why was this new datum selected?

Latitude, longitude, and altitude.

What three (3) grid systems can GPS units be set-up to use?

Control Data

What type of positions is required for differential correction?

The SPCS was intended as a simple rectangular system on which plane geometry and trigonometry could be applied for surveying and was less awkward than working with spherical coordinates.

What were the intentions for developing the state plane coordinate system?

A. 1978

What year was the first GPS satellite launched? A. 1978 B. 1975 C. 1998 D. 1995

B. 1995

What year was the full constellation of satellites achieved? A. 1988 B. 1995 C. 1998 D. 1985

Healthy trees will be red, and unhealthy trees will be yellow.

When interpreting color infrared images, what color will healthy trees be? What about unhealthy trees?

A. Small Scale

When mapping a large land area without great detail you are doing which type of scale of mapping? A. Small Scale B. Diffuse Scale C. Non-detail Scale D. Large Scale

D. Large Scale

When mapping a small land area with great detail you are doing which type of scale of mapping? A. Detail Scale B. Diverse Scale C. Small Scale D. Large Scale

Selective Availability was made inactive in May 2000.

When was Selective Availability made inactive?

A. Sun

Where does the atmosphere receive its energy? A. Sun B. Rotation of the earth C. CO D. Equator

Halfway around the earth is 180 degrees and marks what is called the International Date Line.

Where is the International Date Line?

Zones 15 and 16.

Which UTM zones cover Mississippi?

Zones 10-19.

Which UTM zones cover the continental U.S.?

D. PCC

Which coordinate system can GPS units not be set up to use? A. LLA B. UTM C. SPC D. PCC

Clarke ellipsoid of 1866

Which ellipsoid did NAD27 use as its reference?

D. tracking dementia inflicted

Which of the following GPS application is not usually associated with forestry or natural resource management? A. Aid in Navigation B. Acreage Determination C. Site Mapping D. tracking dementia inflicted

B. Photographic Imagery

Which of the following is considered to be the oldest form of remote sensing? A. Radar Imagery B. Photographic Imagery C. Microwave Imagery D. Thermal Imagery

B. Rectangular

Which of the following is not a developable surface or basic form of projecting maps? A. Conic B. Rectangular C. Azimuthal D. Cylindrical

A. Color Infrared

Which of the following is not an example of non-photographic imagery? A. Color Infrared B. Ultraviolet Sensing C. Radar D. Thermal Infrared

D. 1:15,840

Which pure scale or representative fraction associated with a map or photo yields 40 acres per square inch? A. 1 inch = 2083 feet B. 1 inch = 1320 feet C. 1:25,000 D. 1:15,840

C. Tone

Which term relates to the reflective characteristics of objects within the photographic spectrum? A. Texture B. Surface C. Tone D. Consistency

World Geodetic System 1984 (WGS-84), North American Datum of 1927 (NAD27), and North American Datum of 1983 (NAD83).

Which three Geodetic datum will primarily concern us?

U.S. Department of Defense (DOD); Global Positioning System is the official name for GPS.

Who operates and maintains GPS satellites and what is the official name os GPS?

Polar diameter is the axis of rotation for the earth.

Would the polar diameter or equatorial diameter be the axis of rotation for the earth?