Midterm 1 Flashcards
(126 cards)
1
Q
What is geospatial data
A
geospatial data is any data with an associated location
2
Q
What does the term GIS mean
A
Geographic information system. GIS is computer based mapping and analysis
3
Q
What is GPS(global positioning system)
A
Acquisition of real time location information from satellites
4
Q
What is remote sensing
A
Acquisition of data and imagery from use of satellites
5
Q
What are the three basic systems that make up geospatial technology
A
GIS, Remote sensing, and GPS.
6
Q
What makes geospatial data unique?
A
GIS is used in a wide variety of fields, such as homeland security, forestry, city planning.
7
Q
Describe why geospatial technologies can be considered “geography in action.
A
GIS technologies can be considered geography in action because you are using basic geography concepts but through technology.
8
Q
Describe how the discipline of geography is fundamental to understanding geospatial technology
A
the discipline of geography deals with where things are and why they are where they are. this is fundamental to understanding GIS because GIS deals with spatial thinking constantly.
9
Q
Tweets sent by Twitter users can be mapped using __________.
A
geotagging
10
Q
Some online subscription services like Amazon Prime limit what movies can be streamed and downloaded when the user is outside the United States. What information is used to determine where the user’s computer is located?
A
IP address
11
Q
Which job field uses geospatial technology for national security and defense applications?
A
geospatial intelligence
12
Q
What projections does the SPCS use? Select all that apply.
-Azimuthal Equidistant projection
-Lambert Conformal Conic projection
-Mercator projection
-Transverse Mercator projection
A
Lambert Conformal Conic projection, and Transverse Mercator projection
13
Q
A datum represents __________.
A
a reference surface used in computing coordinates
14
Q
What marks the difference between north and south latitude?
A
equator
15
Q
The SPCS is used only for data from the __________.
A
United States
16
Q
The shortest distance between two points on a sphere is the __________ distance.
A
great circle
17
Q
How are negative values avoided in the UTM system when locating features south of the Equator?
A
by measuring from a false northing
18
Q
Which of these is equal to 2.5 decimal degrees of latitude?
-2 degrees, 5 minutes, 0 seconds of latitude
-2 degrees, 30 minutes, 0 seconds of latitude
-2 minutes, 5 seconds of latitude
-250 minutes, 0 seconds of latitude
A
2 degrees, 30 minutes, 0 seconds of latitude
19
Q
What is a datum
A
a reference surface or model that is used for plotting locations anywhere on the actual surface of earth. The datum represents the size and shape of earth.
20
Q
What is an ellipsoid
A
model of earths shape, larger at the center than the poles.
21
Q
what is a geoid
A
places earths surface at mean sea level to account for the pole differences
22
Q
What is the difficulty of datums
A
they are a reference point and there are 100’s of them. some are global and some local.
23
Q
What is a datum transformation
A
The process of changing measurements from one datum to another.
24
Q
what is the prime meridian
A
The line of longitude that runs through greenwhich england and servers as the - degree line of longitude from which to base measurements servers as the starting point of 0.
25
which direction are negative values in the GCS coordinate system
negative values are used to indicate W or S
26
Describe how datums and the geographic coordinate system of latitude and longitude are used to reference locations on the Earth’s 3D surface
Geographic coordinate system(GCS) is a global reference system which uses lines of lat and long to find exact positions. The equator serves as the starting point with points running north to south, and the prime meridian serves as the starting point of 0 running east to west. GCS measurements are made in degrees minutes and seconds and can locate any point.
27
Explain the difference between measurements made on a 3D world vs those made on a 2D flat surface
The difference between measurements made in 3D and 2D is that measurements in 3D are those in the real world. Measurements in 2D are those made on projections. Projection measurements are different because they are translating our real 3D world to a 2D world.
28
Describe how spatial data are projected onto a 2D flat developable surface of a cylinder, cone or flat plane.
The process of projecting a map involves the use of a developable surface or a flat area on which the locations from earth can be placed. The three main developable surfaces are cylinder, cone, or a flat surface. The place where earth surface touches is the point of tangency and where the map is least distorted
29
Explain the tranverse mercator projection
This is a cylindrical projection. its used for north to south areas. it becomes more distorted the further away you move form the equator
30
Lambert conformal conical
This is a conical projection used for east to west tending areas.it becomes more distorted the further away you move from its lines of tangency.
31
what is Universal tranverse mercator(UTM) and how do you find a point using it
UTM is a grid system that locates coordinates and it works by translating real world locations to a 2d surface. it does not cover the polar regions.
steps
1.)UTM has 60 sections each 6 degrees wide, first find what section you are in.
2.)UTM uses meters with X and Y coordinates. These coordinates are either easting or northing. For north locations count the meters. For south locations negatives can not be used, so count the meters as negative then add 10,000,000 meters this is called false northing
3.)Then measure the points of easting. UTM has no meridian and uses a base point at 500,000 meters. to the east you add and to the west you subtract. This is false easting which is a west or east measurement based on an imaginary meridian.
-when using false northing or easting this must be noted.
32
what is SPCS and how do you locate a point using it
SPCS is similar to UTM. Uses NAD 27 and NAD 83, used for city and county data
1.)SPCS is based on state zones, determine the zone you are in
2.)determine northing and easting measurements now in feet
3.)two projections used
-Tranverse Mercator used for north to south oriented states. States using this projection have their baseline origin 500,000 feet to the west of the principle meridian.
-lambert conical- used for west to east facing states. states using this projection have their baseline at 2,000,000 feet west of the meridian.
33
What is GNSS
GNSS is what more accurately describes GPS. it stands for global navigation satellite system; an overall term for describing technology that uses signals from satellites to find locations on earths surface.
34
What is GPS
Name orginates from NAVSTAR GPS which was developed by the department of defense as a U.S. global positioning system. Technically GPS only really accurately describes the U.S.
35
What is NAVSTAR
NAVSTAR is the U.S. global positioning system
36
What is trilateration and describe how it works and why it needs 4 satellites.
-2dtrilaterion: the process of finding your position relative to three points of reference.
-3dtrilateration:the process of finding a location on Earth’s surface in relation to the positions of three satellites
-how it work: A receiver is finding its position relative to three satellites and using the intersections of these 3d circles to determine where you are located.
-Why we need 4 satellites: only 3 satellites are actually needed to find where you are but a 4th satellite is needed to correct for errors in the receivers clock. this is because most receivers don't have atomic clocks. The position you recieve is measured using WGS84
37
What are the three basic components of NAVSTAR GPS and describe each one
1.)space segment: Made of numerous satellite's and the signals they broadcast
2.)control segment: The series of worldwide ground stations that receive signals and report back to the master control station at Schriever air force base in Colorado
3.)user segment: consists of GPS receivers on the ground that pick up signals. Receivers can only receive signals it CAN NOT transmit back
38
which datum does NAVSTAR GPS use
WGS84
39
what frequency can single and duel receivers pick up.
single: L1
dual: L1 and L2
40
The use of a base station or other earth-bound source to transmit a correction signal to a GPS receiver is known as __________.
DGPS (Differential GPS)
41
Of the following locations, where is a user most likely to experience multipath errors? Select all that apply.
-a city street lined with tall buildings
-a stream running through a deep canyon
-a tree-covered hiking trail
-an open field of soybeans
-a city street lined with tall buildings
-a stream running through a deep canyon
-a tree-covered hiking trail
42
What is the official name of the U.S. global positioning system?
NAVSTAR GPS
43
What component of GPS includes the series of ground stations that help maintain GPS?
control segment
44
Which statement is correct concerning GPS signals and codes?
a.)The C/A and P codes are transmitted on L1 and L2.
b.)The C/A code is transmitted on L1 and L2, and the P code is transmitted on L2.
c.)The C/A code is transmitted on L1, and the P code is transmitted on L1 and L2.
d.)The C/A code is transmitted on L1, and the P code is transmitted on L2.
The C/A code is transmitted on L1, and the P code is transmitted on L1 and L2.
45
When do multipath errors occur?
when the GPS signal is reflected from local objects, causing the signal to be delayed
46
Of the following, what methods can be used to improve the accuracy of GPS positional measurements? Select all that apply.
-CORS
-FAA
-DGPS
-GPX
-DGPS
-CORS
47
Which of these is designed to operate in Japan?
-BeiDou-2
-Eisei
-IRNSS
-QZSS
-QZSS
48
Who has access to the P code?
military personnel
49
What is PDOP
error introduced by poor satellite arrangement. Lower value = better. Caused by geometric position.
-typically 5 meters off
-the further satellites are from one another and the wider the angle the more accurate measurements will be.
50
what is differential correction. (DGPS)
differential Gps: a method of using a ground-based correction in addition to satellite signals to determine position.
-because base station knows its own coordinates it is able to provide correction
-reduced to 5 meters or less
51
what is WAAS
WAAS(wide area augmentation system): a satellite-based augmentation system that covers the united states and other portion of North America.
-WAAS reduces position error to 3 meters or less by using a series of base stations
-One issue with WAAS is that it functions only within the United States.
52
What is a multipath error
an error caused by delay in signals due to reflecting surfaces before reaching receiver.
53
What is CORS
CORS(continuously operating reference stations): operated by national geodetic survery to provide ground based method of obtaining more accurate GPS positioning.
54
describe how WAAS and differential correction(DGPS) are similar and different
Similarities: Both WAAS and DGPS use a series of base stations to calculate correction information. Both operate on the same principle of some sort of correction is calculated and transmitted to a receiver and the receiver uses that information to determine its position.
Differences: WAAS only broadcasts to WAAS satellites.
55
What is a vector data model
-a vector data model conceptualizes the world as a series of vector objects.
These objects include points(zero dimensional objects), lines(one dimensional objects) and polygons(two dimensional objects).
-best for representing things that have distinct boundaries
56
What is a rater data model
-a model for representing spatial data with utilizes a series of equally spaced grid cells.
-grid cell: a square unit representing some real-world size that contains a single value. Each represents some area on earth's surface.
57
What is the national land cover data base (NLCD)
-a raster-based GIS dataset that maps the land cover types for the entire united states at a 30 meter resolution.
-every cell has a specific land cover type.
58
what is an attribute table
a spreadsheet style form whose rows consist of induvial object's, and the columns are the attributes associated with those objects.
59
what is an attribute
non spatial data that can be associated with a spatial location
60
what is nominal data
a type of data that is a unique identifier of some kind. If numerical the differences between numbers is NOT significant(social security numbers, phone numbers, etc....)
61
what is ordinal data
a type of data the refers solely to a ranking of some kind.
-deals SOLELY with ranking not the numbers associated with those ranking (car race only the places tracked NOT the winning times)
62
What is interval data
a type of data in which the differences between numbers is significant, but there is no fixed non-arbitrary zero point associated withe data (example is temperature)
-with this type of data dividing does not work.
63
What is ratio-data
a type of data in which the differences between numbers is significant, but there is a non-arbitrary zero point associated with the data. (age or weight because person can not be less than 0 in these categories).
-used when comparing multiple sets of numbers
64
what is metadata and what are the guidelines
-descriptive information about geospatial data --FGDC (federal geographic data committee) format and standards for metadata
standards:
-Identification (a description of the data set)
-Data quality(information about accuracy of the data)
-Spatial data organization information(is it vector or raster data)
-spatial reference information
-Distribution
-metadata reference
-citation information
65
What are the differences between discrete object view and continuous field view of locations in the real world.
-continuous field view: a conceptualization of the world in which all items very across the earths surface as constant fields, and value are available al all locations along those fields. This type of data is best for representing things like temperature or atmospheric pressure because they vary across earth.
-discrete object view: a conceptualization of the world in which all reality can be represented by a series of separate objects, each having a fixed location of fixed beginning and end locations.
66
describe how GIS allows a user to store and link spatial data (locational) to non-spatial data(attribute)
- attribute data is in four forms nominal, ordinal, interval, and ratio. Each layer in GIS has an associated attribute table where the objects are stored as records(rows) and the attributes are stored as fields(columns).
-you can use the join feature in GIS to connect non-spatial data to spatial locations. this works by linking information for records in one table corresponding to records in another table
-raster and vector data cant be handled the same way in an attribute table. Raster data is composed of millions of cells. Raster data is often set up in a table with each record featuring the value for a taster cell and an attribute table showing the count of how many cells comprise the dataset.
67
Explain how the resolution of a grid cell relates to distance and area on the earths surface in the raster model data.
in a raster data set the data is represented using equally sized and spaced grid cells. Each grid cell represents the same amount of area on the ground. Spatial resolution of data refers to the dimension of the cell size representing the area covered on the round. When a model set has higher resolution this means it has more cells per unit area this causes a more crisp and accurate depiction of distance and area.
68
what is the join feature
a method of linking two ore more tables together but it only works if the tables have a field in common.
69
What is SQL
SQL(structured query language): language for building queries whose format is much like a mathematical function.
70
What are the six relational operators and how do they function
1. = (equal)
2.<>(not equal)
3.>(greater than)
4.<(less than)
5.>= (greater or equal to)
6.<=(less than or equal to)
71
what is a Boolean operator
one of four connectors used to build compound queries.
72
What is the AND operator
will return values that match both criteria set. referred to as an intersection:(chosen features are those that meet both criteria in the query)
73
What is the OR operator
records that meet one or both criteria being selected also called a union:(chosen features are all that meet the first criterion as well as all that meet the second criterion in the query)
74
What is the NOT operator
query built around the concept that you want all of the data related to one criterion but want to exclude what is related to a second (including where two criterion overlap in the query) also called a negotiation
75
what is the XOR operator
query built around the idea that you want all the data from each layer except for that the layers have in common referred to as exclusive or:( because it acts like a union but leaves out intersection data. Example find cities with high population and income but not types of cities)
76
what is a spatial query
a query that involves selecting records or object's from one layer based on their spatial relationship with other layers.
77
what is an overlay operation
the combination of two or more layers in GIS that share some of the same spatial boundaries
78
what is the buffer process
a polygon of spatial proximity built around a feature. examining features in a boundary
79
what is the dissolve process
the ability of GIS to combine polygons that have the same features. Good for examining regions
80
what is the intersect process
Only the features that two layers have in common are retained.
81
what is the identity process
all features of an input layer are retained and all features of a second layer that intersect with them are also retained
82
what is the symmetrical differences process
all features of two layers are retained except areas they have in common
83
what is the union(overlay) process
all features of two layers are combined together in a new layer
84
what is map algebra and how is it used
-the use of simple mathematical operators to combine data sets.
-its a grid of 0 or 1 values. 1=criterion met, 0=not met, when combining multiple criteria values are combined. a higher number means more criteria are met.
-can be used for site suitability and site suitability index(a system where locations are ranked based on how well they fit a set of criteria)
85
what is a suitability index
suitability index: a system where locations are ranked based on how well they fit a set of criteria.
86
What is MCE?
multi-criteria evaluation: The use of several factors to determine the suitability of a site for a particular purpose.
-uses "pressures" to determine suitability
87
what is LTM?
Land transformation model: combines various weighted raster models in order to determine where areas have changed to urban areas.
88
define the term spatial analysis and provide an example from your discipline
-spatial analysis is the process of analyzing spatial data by using Boolean operators or relational operators to give information about what raster or vector data is conveying. One example of spatial analysis in forestry is the creation of stream buffers. in order to comply with the Oregon forests practice act stream buffers must be set up and maintained pre and post-harvest which GIS can help due with spatial analysis commands such as buffer.
89
how does an SQL query allow the user to create a subset of geospatial data based on specific queries of the non-spatial attribute data.
SQL uses specific operators that act in a similar way to a mathematical function. It is able to find attributes that meet certain conditions.
Example: a layer made up of points representing cities in OHIO also has a number of fields representing its attributes such as city names, population, etc. if you wanted to do an analyze these records you could make a query that states CITY_NAME= boardman to find all records that match.
90
how is a spatial query different from a SQL attribute query.
an SQL query involves finding certain attributes that meet conditions. A spatial query involves selecting records or objects from layers based on their spatial relationships. SQL does not care about spatial relationships.
-An SQL is a database query that retrieves data solely based on the criteria you set. While a spatial query is specifically designed to handle and retrieve data based on geometric properties.
91
what is cartography
The art and science of creating and designing maps
92
what is the visual hierarchy
how features are displayed on a map to emphasize their level of prominence.
the level of prominence will depend on what the maps purpose is and what its being made for.
93
What is a small-scale map and what are its features?
a small-scale map has a small RF value. EX: 1:250,000. It shows large geographic regions and generally shows less detail than a large scale map.
94
what is a large-scale map and what are its features?
a large-scale map shows small geographic regions and have larger RF values EX 1:40,000. The largest RF value a map can have is 1:1. This map type shows more detail and more data.
94
What is a reference map
A reference map is a map that servers to show the locations of features rather than thematic information. An example would be a road map or trail map.
95
What is a thematic map
a thematic map conveys information about one particular theme to the reader. An example of a thematic map would be state by state population increases
96
what is a choropleth map?
type of thematic map which data is displayed according to one of the several different classifications.
97
What is a legend on a map
a graphical device used to explain what the various map symbols and colors represent.
98
what is a scale bar
a scale bar is a graphical device used on a map to represent map scale.
99
what are the three basic questions that underlie intentional map making.
1.)define a purpose of the map (audience/context)
2.)convey that purpose clearly (design a visual hierarchy)
3.)arrange a layout
100
what are the four data classifications on a choropeth map
-natural breaks
-quantile
-equal intervals
-standard deviation -
101
what is a natural break
a data classification model that involves selecting class break levels by searching for spaces in the data values
102
what is a quantile
a data classification method that involves attempting to place an equal number of data values in each class
103
what is equal intervals
method that creates a number of equally sized ranges and then splitting the data values among those ranges
104
what is standard deviation
the average distance of a single data value from the mean
105
what are the main cartographic elements on a map
-legend
-north arrow
-scale bar
-type(the lettering used)
-label(text placed on map to identify features
-neatline
106
Polygons representing land parcels by owner on a county parcel map is an example of what type of data?
nominal
107
What organization developed ArcGIS?
Esri
108
Streams on a map are symbolized by the number of available fishing days. What type of data is this?
ratio
109
The NHD contains GIS data for which of these?
-land cover types
-political boundaries
-surface transportation
-water bodies
water bodies
110
What relationships does topology establish between vector objects? Select all that apply.
-adjacency
-connectivity
-containment
-distance
-adjacency
-connectivity
-containment
111
How is spatial data represented in the raster data model?
as areas using equally spaced and equally sized grid cells
112
What model is used to represent the data in the NHD?
vector
113
In the context of GIS, what is topology?
the spatial relationships among objects that are independent of their coordinates
114
When modeling the world in GIS, features treated as objects with definite locations and boundaries describe a __________ view of the world.
discrete object
115
What model is used to represent the data in the NLCD?
raster
116
Of the following choices, which one best describes geoprocessing?
-applying an action to one or more datasets that results in the creation of a new dataset
-identifying the common features across multiple datasets based on a suitability index
-querying a database to determine which records will most likely satisfy an SQL query
- using a Boolean or relational operator in a simple or compound SQL query
-applying an action to one or more datasets that results in the creation of a new dataset
117
Which one of the following Boolean operators will return all the data in multiple datasets except for the intersection of those datasets?
-AND
-NOT
-OR
-XOR
-XOR
118
Of the following choices, which one best describes SQL?
-It is a standard quotient language used to manage large spatial datasets.
- It is a software query language used to join databases of the same area.
- It is a spatial quotient language used to overlay georeferenced datasets.
-It is a structured query language used to retrieve information from databases.
-It is a structured query language used to retrieve information from databases.
119
Which geoprocessing operation will merge selected features from one dataset with selected features from another dataset?
-identity
-intersect
-symmetrical difference
-union
union
120
Of the following geoprocessing operations, which one will select all areas from two datasets except those areas they have in common?
-identity
-intersect
-symmetrical difference
-union
-symmetrical difference
121
Which one of the following data classification methods attempts to place an equal number of data values in each class?
-equal intervals
-natural breaks
-quantiles
-standard deviations
-quantiles
122
Of the following data formats, which one will result in the least loss of a map graphic's data?
-DPI
-JPEG
-PDF
-TIFF
TIFF
123
Which one of the following data classification methods determines breakpoints by dividing the range of values by the desired number of classes?
-equal intervals
-natural breaks
-quantiles
-standard deviations
-equal intervals
124
What are the differences between a GeoPDF and a regular PDF? Select all that apply.
-The GeoPDF allows users to make map measurements.
-The GeoPDF normalizes the user's map data.
-The GeoPDF permits users to interact with map layers.
-The GeoPDF provides users with lossless compression.
-The GeoPDF allows users to make map measurements.
The GeoPDF permits users to interact with map layers.
125
What color scheme should be used when designing maps for display on a computer screen?
RGB
