GISP FINAL EXAM
• Satellites in the are arranged into six equally-spaced or-bital
planes surrounding the Earth. Each plane contains four "slots" occupiedby baseline satellites.
This 24-slot arrangement ensures users can view at least four satellites from virtually any
point on the planet.: GPS Constellation
• Russia's global navigation system. Fully operational worldwide.: -
GLONASS
• A global system being developed by the European Union and other partner countries, which
began operation in 2016 and is expected to be fully deployedby 2020: Galileo
• People's Republic of China's regional system, currently limited to Asia and the West Pacific,
global coverage planned to be operational by 2020: Beidou
• A regional navigation system developed by the Indian Space Research Organisation:
IRNSS
• A regional navigation system in development that would be receivablewithin Japan:
QZSS
• launched by the U.S. Department of Defense in for use by the
United States military and became fully operational in 1995. It was allowed forcivilian use in
the 1980s, although the US govt can selectively deny access tothe system: 1973
• The of an artificial satellite system is one of its
three operational components (the others being the user and ground
segments). It comprises the satellite or satellite constellation and the uplinkand downlink
satellite links.: Space segment
• Consists of a global network of ground facilities that track the GPS satel- lites, monitor
their transmissions, perform analyses, and send commands and data to the constellation: GPS
Control Segment
• This includes a master control station, an alternate master control station, 11 command and
control antennas, and 16 monitoring sites.: Operational Con-trol Segment (OCS)
• Consists of the GPS receiver equipment, which receives signals from the GPS Satellites
and uses the transmitted information to calculate the user's
3-dimensional position and time.: GPS User Segment
• A positioning and timing service for peaceful civil, commercial, and sci- entific use. It is
provided by way of ranging signals broadcast at the GPS L1 frequency.The L1 frequency,
transmitted by all satellites, contains a coarse/ac-quisition (C/A) code ranging signal, with a
navigation data message.: StandardPositioning Service (SPS)
,• Computed by measuring the time interval between the transmission andreception of a
satellite signal: Distance calculation (GPS)
• Distances of at least 3 GPS satellites are used to determine the position of the GPS receiver.
Satellites broadcast signals as a sphere - Where all spheres intersect determines the position of
the GPS receiver: Trilateration
• Dependent on: type of GPS receiver, field techniques, post processing,error from various
sources: Field Data Accuracy
• Recreational grade, Mapping grade, Survey or High Accuracy grade: GPSReceiver types
• Caused by reflected GPS signals arriving at the GPS receiver (e.g. nearbystructures and
other reflective surfaces): Multipath errors
• GPS signals can experience delays when traveling through the atmos- phere. Common
conditions are tropospheric and ionospheric delays: Atmos-pheric errors
• Differential correction will increase the quality of data, but accuracy is de- graded slightly
as the distance from the increases:
BaseStation
• Intentional degradation of the GPS signals by the DoD to limit accuracyfor non-US
military/govt users - currently turned off, but can turn on any time: Selective availability
• The distortion of the satellite signal prior to reaching the GPS receiver and/or additional
signal piggy-backing onto the GPS satellite signal.: Noise
• Collect data when there are an optimal number of satellites (4+), and when satellites are
configured in a way that produces lower
values (6 or less). Higher values = less reliable data.: Position Dilution of Precision
(PDOP)
• This value should be set higher to help minimize noise error (user manu- facturer
recommendations): Signal to Noise Ratio mask (SNR)
• This is the default angle to minimize the amount of atmosphere through which the
satellite signal must travel. Should be set to 15 degrees.: Elevationmask
• Recommendation is to collect point data at 1-second intervals (same collection interval as
base station), collect polygon and line data at 5-secondintervals: Data collection rate (sync
rate)
• GPS receivers are designed to collect positions relative to this: WGS84datum
• Degrees minutes seconds : 40° 262463N 79° 582563WDegrees decimal minutes: 40°
26.7672N 79° 58.9332W
Decimal degrees: 40.446° N 79.982° W: Formats for measuring Latitude & Longi-tude
• There are in one degree: 60 minutes
,• There are in one minute: 60 seconds
• There are seconds in one degree: 3600 seconds
• Latitude in the southern hemisphere is : Negative
• Latitude in the northern hemisphere is : Positive
• Longitude in the western hemisphere is : Negative
• Longitude in the eastern hemisphere is : Positive
• Spatial reference system measured in Northings & Eastings (e..g.4740283N, 434057E):
UTM
• A United States government committee which promotes the coordinated development, use,
sharing, and dissemination of geospatial data on a nationalbasis.: Federal Geographic Data
Committee (FGDC)
• Content standard that adds elements to describe imagery and gridded data as well as data
collected using instruments (monitoring stations andmeasurement devices): ISO 19115-2
• This is product-oriented and focuses on defect identification - finding andeliminating
sources of quality problems.: Quality control
• Captures, manages and analyzes data changes (most often done with data-bases): Archiving
• The science and technology of gathering, analyzing, interpreting, distribut- ing, and using
geographic information (includes surveying, mapping, remotesensing, GIS, GPS).: Geomatics
• Combines multiple input datasets of the same data type into a single newoutput: Merge
• Extracts input features that overlay the clip features (keeps the input'sattributes): Clip
• Extracts features which overlap in all layers to a new feature class (joins theattribute tables):
Intersect
• Based on the principle that the 3D location of any point can be determinedby measuring
angles and distances from other know points: Ground surveying
• Expensive and time consuming: Disadvantages of ground surveying
• Receives signals from GPS satellites to calculate the current position andtime. Four
satellites must be in view for it to compute four unknown quanti- ties (three position
coordinates and clock deviation from satellite time): GPSreceiver
• 1. Determine the result of the field work
2. Determine what needs to be collected, inspected or surveyed (Set up a fieldcollection
form/data dictionary)
3. Determine how it will be collected (Pen and paper, mobile tablet,Trimble unit,drone)
4. Begin field collection on a good representation of the entire dataset
5. Review sample field collection and adjust the data being collected or themethod of
, collection
6. Plan locations and timing for field work
7. Conduct field collection for all assets.: Field collection process
• The shape that the surface of the oceans would take under the influence ofthe Earth's
gravitation and rotation alone in the absence of other influences such as winds and tides. It is a
model of global mean sea level that is used to
measure precise surface elevations by registering the ocean's water level atcoastal places
using tide gauges. The radius at the equator is larger than at the poles due to the long term
effects of the earth's rotation. Mountains havemore mass than valleys, thus the pull of gravity
is regionally stronger near mountains.: Geoid
• This is a mathematically defined surface that approximates the geoid, thetruer figure of
the Earth, or other planetary body.: Reference ellipsoid
• Fits the geoid to a first order approximation, which is formed when anellipse is rotated
about its minor axis.: Oblate ellipsoid
• As can be seen from the dimensions of the Earth ellipsoid, the semi-majoraxis a and the
semi-minor axis b only by a bit more than 21 km.: Sphere
• Given a point (in terms of its coordinates) and the direction (azimuth) and distance from
that point to a second point, determine (the coordinates of) that second point.: First (direct)
geodetic problem
• Coordinate-based local, regional, or global system used to locate geo-graphic entities.:
Spatial reference system (SRS)
• Given two points, determine the azimuth and length of the line (straightline, arc or
geodesic) that connects them.: Second (inverse) geodetic problem
• Coordinate-based local, regional, or global system used to locate geo-graphic entities.:
Coordinate reference system (CRS)
• Transforming coordinates from a curved earth to a flat map using a grid oflines of latitude
and longitude: Map projection
• Model of the earth as a spheroid (2 components, reference ellipsoid and aset of survey
points both the shape of the spheroid and its position relative to the earth, i.e. by 'attaching' the
ellipsoid to a monument on the earth's surface): Horizontal datum
• Reference point for elevations of surfaces and features on the earth. Couldbe based on tidal,
sea levels, gravimetric, based on a geoid.: Vertical datum
• Gravity based geodetic datum in North America: NAVD88
• Projection: preserves shape and direction, area gets distorted - projecting earth onto a
cylinder tangent to a meridian.: Mercator projection
• Satellites in the are arranged into six equally-spaced or-bital
planes surrounding the Earth. Each plane contains four "slots" occupiedby baseline satellites.
This 24-slot arrangement ensures users can view at least four satellites from virtually any
point on the planet.: GPS Constellation
• Russia's global navigation system. Fully operational worldwide.: -
GLONASS
• A global system being developed by the European Union and other partner countries, which
began operation in 2016 and is expected to be fully deployedby 2020: Galileo
• People's Republic of China's regional system, currently limited to Asia and the West Pacific,
global coverage planned to be operational by 2020: Beidou
• A regional navigation system developed by the Indian Space Research Organisation:
IRNSS
• A regional navigation system in development that would be receivablewithin Japan:
QZSS
• launched by the U.S. Department of Defense in for use by the
United States military and became fully operational in 1995. It was allowed forcivilian use in
the 1980s, although the US govt can selectively deny access tothe system: 1973
• The of an artificial satellite system is one of its
three operational components (the others being the user and ground
segments). It comprises the satellite or satellite constellation and the uplinkand downlink
satellite links.: Space segment
• Consists of a global network of ground facilities that track the GPS satel- lites, monitor
their transmissions, perform analyses, and send commands and data to the constellation: GPS
Control Segment
• This includes a master control station, an alternate master control station, 11 command and
control antennas, and 16 monitoring sites.: Operational Con-trol Segment (OCS)
• Consists of the GPS receiver equipment, which receives signals from the GPS Satellites
and uses the transmitted information to calculate the user's
3-dimensional position and time.: GPS User Segment
• A positioning and timing service for peaceful civil, commercial, and sci- entific use. It is
provided by way of ranging signals broadcast at the GPS L1 frequency.The L1 frequency,
transmitted by all satellites, contains a coarse/ac-quisition (C/A) code ranging signal, with a
navigation data message.: StandardPositioning Service (SPS)
,• Computed by measuring the time interval between the transmission andreception of a
satellite signal: Distance calculation (GPS)
• Distances of at least 3 GPS satellites are used to determine the position of the GPS receiver.
Satellites broadcast signals as a sphere - Where all spheres intersect determines the position of
the GPS receiver: Trilateration
• Dependent on: type of GPS receiver, field techniques, post processing,error from various
sources: Field Data Accuracy
• Recreational grade, Mapping grade, Survey or High Accuracy grade: GPSReceiver types
• Caused by reflected GPS signals arriving at the GPS receiver (e.g. nearbystructures and
other reflective surfaces): Multipath errors
• GPS signals can experience delays when traveling through the atmos- phere. Common
conditions are tropospheric and ionospheric delays: Atmos-pheric errors
• Differential correction will increase the quality of data, but accuracy is de- graded slightly
as the distance from the increases:
BaseStation
• Intentional degradation of the GPS signals by the DoD to limit accuracyfor non-US
military/govt users - currently turned off, but can turn on any time: Selective availability
• The distortion of the satellite signal prior to reaching the GPS receiver and/or additional
signal piggy-backing onto the GPS satellite signal.: Noise
• Collect data when there are an optimal number of satellites (4+), and when satellites are
configured in a way that produces lower
values (6 or less). Higher values = less reliable data.: Position Dilution of Precision
(PDOP)
• This value should be set higher to help minimize noise error (user manu- facturer
recommendations): Signal to Noise Ratio mask (SNR)
• This is the default angle to minimize the amount of atmosphere through which the
satellite signal must travel. Should be set to 15 degrees.: Elevationmask
• Recommendation is to collect point data at 1-second intervals (same collection interval as
base station), collect polygon and line data at 5-secondintervals: Data collection rate (sync
rate)
• GPS receivers are designed to collect positions relative to this: WGS84datum
• Degrees minutes seconds : 40° 262463N 79° 582563WDegrees decimal minutes: 40°
26.7672N 79° 58.9332W
Decimal degrees: 40.446° N 79.982° W: Formats for measuring Latitude & Longi-tude
• There are in one degree: 60 minutes
,• There are in one minute: 60 seconds
• There are seconds in one degree: 3600 seconds
• Latitude in the southern hemisphere is : Negative
• Latitude in the northern hemisphere is : Positive
• Longitude in the western hemisphere is : Negative
• Longitude in the eastern hemisphere is : Positive
• Spatial reference system measured in Northings & Eastings (e..g.4740283N, 434057E):
UTM
• A United States government committee which promotes the coordinated development, use,
sharing, and dissemination of geospatial data on a nationalbasis.: Federal Geographic Data
Committee (FGDC)
• Content standard that adds elements to describe imagery and gridded data as well as data
collected using instruments (monitoring stations andmeasurement devices): ISO 19115-2
• This is product-oriented and focuses on defect identification - finding andeliminating
sources of quality problems.: Quality control
• Captures, manages and analyzes data changes (most often done with data-bases): Archiving
• The science and technology of gathering, analyzing, interpreting, distribut- ing, and using
geographic information (includes surveying, mapping, remotesensing, GIS, GPS).: Geomatics
• Combines multiple input datasets of the same data type into a single newoutput: Merge
• Extracts input features that overlay the clip features (keeps the input'sattributes): Clip
• Extracts features which overlap in all layers to a new feature class (joins theattribute tables):
Intersect
• Based on the principle that the 3D location of any point can be determinedby measuring
angles and distances from other know points: Ground surveying
• Expensive and time consuming: Disadvantages of ground surveying
• Receives signals from GPS satellites to calculate the current position andtime. Four
satellites must be in view for it to compute four unknown quanti- ties (three position
coordinates and clock deviation from satellite time): GPSreceiver
• 1. Determine the result of the field work
2. Determine what needs to be collected, inspected or surveyed (Set up a fieldcollection
form/data dictionary)
3. Determine how it will be collected (Pen and paper, mobile tablet,Trimble unit,drone)
4. Begin field collection on a good representation of the entire dataset
5. Review sample field collection and adjust the data being collected or themethod of
, collection
6. Plan locations and timing for field work
7. Conduct field collection for all assets.: Field collection process
• The shape that the surface of the oceans would take under the influence ofthe Earth's
gravitation and rotation alone in the absence of other influences such as winds and tides. It is a
model of global mean sea level that is used to
measure precise surface elevations by registering the ocean's water level atcoastal places
using tide gauges. The radius at the equator is larger than at the poles due to the long term
effects of the earth's rotation. Mountains havemore mass than valleys, thus the pull of gravity
is regionally stronger near mountains.: Geoid
• This is a mathematically defined surface that approximates the geoid, thetruer figure of
the Earth, or other planetary body.: Reference ellipsoid
• Fits the geoid to a first order approximation, which is formed when anellipse is rotated
about its minor axis.: Oblate ellipsoid
• As can be seen from the dimensions of the Earth ellipsoid, the semi-majoraxis a and the
semi-minor axis b only by a bit more than 21 km.: Sphere
• Given a point (in terms of its coordinates) and the direction (azimuth) and distance from
that point to a second point, determine (the coordinates of) that second point.: First (direct)
geodetic problem
• Coordinate-based local, regional, or global system used to locate geo-graphic entities.:
Spatial reference system (SRS)
• Given two points, determine the azimuth and length of the line (straightline, arc or
geodesic) that connects them.: Second (inverse) geodetic problem
• Coordinate-based local, regional, or global system used to locate geo-graphic entities.:
Coordinate reference system (CRS)
• Transforming coordinates from a curved earth to a flat map using a grid oflines of latitude
and longitude: Map projection
• Model of the earth as a spheroid (2 components, reference ellipsoid and aset of survey
points both the shape of the spheroid and its position relative to the earth, i.e. by 'attaching' the
ellipsoid to a monument on the earth's surface): Horizontal datum
• Reference point for elevations of surfaces and features on the earth. Couldbe based on tidal,
sea levels, gravimetric, based on a geoid.: Vertical datum
• Gravity based geodetic datum in North America: NAVD88
• Projection: preserves shape and direction, area gets distorted - projecting earth onto a
cylinder tangent to a meridian.: Mercator projection
