GIS Exam
Study online at https://quizlet.com/_8ax108
1. Why can getting Poor connection - hardware and software issues; different companies/prod-
points from a GPS ucts/versions
into ArcGIS be prob- Difficult to find the specified datum/projection
lematic?
2. What is remote Collecting information from a distance; ex. photographs or radar/LiDAR.
sensing? Give exam- Typically satellite or air plane. Offer great detail over a continuous surface
ples.
3. How is remote sens- Great detail = large file sizes. Stored using raster data models - typically, three
ing imagery stored? rasters superimposed together to get color (one each for Red, Green, and
Blue value: RGB)
4. How can we pull in- Can often be detected by the human eye and then digitized or classified
formation from re- based on type; but is very time consuming and expensive. Plus, humans can
mote sensing? make mistakes. So we increasingly use computers to pull out the information
correctly. Computers use automatic processing, being trained to write rules to
automatically pull out information. This is hugely beneficial for large datasets.
Not ideal for small areas.
5. What is artificial in- Show computer what to look for and it figures it out; E.g. cancer on a brain
telligence? scan, gentrification on street view. Cutting edge of computer technology -
but humans are unsure of how it actually works. Computer is literally thinking
for itself (training itself). Huge potential moving forward - perhaps someday
replace all humans
6. What is LiDAR? Light Detection and Ranging - similar to SONAR, but uses laser rather than
sound waves. Device sends out a laser pulse, and records how long it takes
for it to bounce off surface and return to detector. Benefits: Highly Accurate;
can penetrate foliage
7.
, GIS Exam
Study online at https://quizlet.com/_8ax108
How are drones Similar to RS from air photos or satellite. However, much cheaper to collect
used in RS and what the information and can be collected by user at will, rather than relying on
is their benefit someone else's satellite.
8. How can smart Because they are hugely powerful data collection devices, with a large num-
phones be used for ber of sensors (accelerometer, GPS, gyroscope, microphone, barometer,
data collection? thermometer). Have lots of storage for data, cloud connections, and high
processing speed. The fact that our phones are constantly collecting data
about us creates massive privacy issues.
9. Define projections Projections compensate for the earth being spherical but being represented
and coordinates. on a flat surface (map)
Coordinates allow us to accurately and reproducibly locate features on the
earth's surface
10. Define geodesy Science of measuring the shape of the earth - humans have been refining the
model for thousands of years
11. Describe earth's Earth is an Ellipsoid, not a perfect sphere. Two radii:
shape. •r1, along semi-major (through Equator)
•r2, along semi-minor (through poles). More specifically, its shape is a geoid,
because it is rough, not smooth, due to differences in internal gravitational
pull. This causes some areas to bulge out while others are sunken.
12. What is essential for The poles and equator
defining x/y coordi-
nates?
13. Define datum. A model of the earth's size/shape (ie a model of the Geoid). Applied to a
specific origin/reference point. Different datums created for places around
the world. Continually refined over time (ex: NAD 27 vs 83). Not much change
in recent decades. Horizontal and Vertical datums exist
, GIS Exam
Study online at https://quizlet.com/_8ax108
14. With projections, is Small scale maps
there more distor-
tion on small scale
or large scale maps?
15. Projections typically Area, shape, distances, and angles
only maintain 1 or
2 of what following
features, and must
distort at least one
feature?
16. Define spherical co- Use the length of a vector originating at the ellipsoid center to define the
ordinates. location on the surface
17. Define latitude and Latitude: Lines running parallel east to west; Equator is the baseline
longitude.
Longitude: Lines running from pole to pole; Meridians; Greenwich (Prime)
Meridian is the baseline from which measurements are made
18. Define UTM. Divides the world into 60 zones (including North and South). Each zone has
an origin based on False Easting/Northing
19. Describe the re- Each layer has a coordinate system, and datum (usually projection) - even if
lationship between it is not defined. All layers on the map must be in the same system to allow
GIS, coordinate sys- them to line up (superimpose). Thus, GIS projects on the fly to one system for
tems, datum and all of the different layers. Data frame has one projection/coordinate system
projections and which is defined by first file added. All others that differ are re-projected on
what happens in GIS the fly to match this one.
when they differ.
20. What is the name of PRJ
the file that contains
Study online at https://quizlet.com/_8ax108
1. Why can getting Poor connection - hardware and software issues; different companies/prod-
points from a GPS ucts/versions
into ArcGIS be prob- Difficult to find the specified datum/projection
lematic?
2. What is remote Collecting information from a distance; ex. photographs or radar/LiDAR.
sensing? Give exam- Typically satellite or air plane. Offer great detail over a continuous surface
ples.
3. How is remote sens- Great detail = large file sizes. Stored using raster data models - typically, three
ing imagery stored? rasters superimposed together to get color (one each for Red, Green, and
Blue value: RGB)
4. How can we pull in- Can often be detected by the human eye and then digitized or classified
formation from re- based on type; but is very time consuming and expensive. Plus, humans can
mote sensing? make mistakes. So we increasingly use computers to pull out the information
correctly. Computers use automatic processing, being trained to write rules to
automatically pull out information. This is hugely beneficial for large datasets.
Not ideal for small areas.
5. What is artificial in- Show computer what to look for and it figures it out; E.g. cancer on a brain
telligence? scan, gentrification on street view. Cutting edge of computer technology -
but humans are unsure of how it actually works. Computer is literally thinking
for itself (training itself). Huge potential moving forward - perhaps someday
replace all humans
6. What is LiDAR? Light Detection and Ranging - similar to SONAR, but uses laser rather than
sound waves. Device sends out a laser pulse, and records how long it takes
for it to bounce off surface and return to detector. Benefits: Highly Accurate;
can penetrate foliage
7.
, GIS Exam
Study online at https://quizlet.com/_8ax108
How are drones Similar to RS from air photos or satellite. However, much cheaper to collect
used in RS and what the information and can be collected by user at will, rather than relying on
is their benefit someone else's satellite.
8. How can smart Because they are hugely powerful data collection devices, with a large num-
phones be used for ber of sensors (accelerometer, GPS, gyroscope, microphone, barometer,
data collection? thermometer). Have lots of storage for data, cloud connections, and high
processing speed. The fact that our phones are constantly collecting data
about us creates massive privacy issues.
9. Define projections Projections compensate for the earth being spherical but being represented
and coordinates. on a flat surface (map)
Coordinates allow us to accurately and reproducibly locate features on the
earth's surface
10. Define geodesy Science of measuring the shape of the earth - humans have been refining the
model for thousands of years
11. Describe earth's Earth is an Ellipsoid, not a perfect sphere. Two radii:
shape. •r1, along semi-major (through Equator)
•r2, along semi-minor (through poles). More specifically, its shape is a geoid,
because it is rough, not smooth, due to differences in internal gravitational
pull. This causes some areas to bulge out while others are sunken.
12. What is essential for The poles and equator
defining x/y coordi-
nates?
13. Define datum. A model of the earth's size/shape (ie a model of the Geoid). Applied to a
specific origin/reference point. Different datums created for places around
the world. Continually refined over time (ex: NAD 27 vs 83). Not much change
in recent decades. Horizontal and Vertical datums exist
, GIS Exam
Study online at https://quizlet.com/_8ax108
14. With projections, is Small scale maps
there more distor-
tion on small scale
or large scale maps?
15. Projections typically Area, shape, distances, and angles
only maintain 1 or
2 of what following
features, and must
distort at least one
feature?
16. Define spherical co- Use the length of a vector originating at the ellipsoid center to define the
ordinates. location on the surface
17. Define latitude and Latitude: Lines running parallel east to west; Equator is the baseline
longitude.
Longitude: Lines running from pole to pole; Meridians; Greenwich (Prime)
Meridian is the baseline from which measurements are made
18. Define UTM. Divides the world into 60 zones (including North and South). Each zone has
an origin based on False Easting/Northing
19. Describe the re- Each layer has a coordinate system, and datum (usually projection) - even if
lationship between it is not defined. All layers on the map must be in the same system to allow
GIS, coordinate sys- them to line up (superimpose). Thus, GIS projects on the fly to one system for
tems, datum and all of the different layers. Data frame has one projection/coordinate system
projections and which is defined by first file added. All others that differ are re-projected on
what happens in GIS the fly to match this one.
when they differ.
20. What is the name of PRJ
the file that contains
