GISP Flashcards
GISP
Spatial Data Model
Objects in a spatial database plus the relationships among them
Coordinates
Used to define the spatial location and extent of geographic objects
Thematic Layers
A spatial representation of analyzed data of elements of the same type
Cartesian Coordinate System
Define two or three orthogonal (right-angle) axes. Two dimensional x, y or Three dimensional x, y and z.
Spherical coordinate system
Uses angular measurements on a sphere to specify locations on a modeled Earth surface
Decimal Degrees Conversion
DD = Deg + MIN/60 + SEC/3600
Attribute data
Used to record the non-spatial characteristics of an entity. Also called items or variables.
Nominal Attributes
Variables that provide descriptive information about an object. May also be images, film clips, audio recording, or other descriptive information.
Ordinal attributes
Imply a ranking or order by their values.
Interval/Ratio attributes
Used for numeric items where both rank, order and absolute difference in magnitudes are reflected in the numbers.
Domain
Range of values an item may take
Conceptualization
A view of real world phenomena or entities as spatial objects
Vector Data Model
Use discrete elements such as points, lines, and polygons to represent the geometry of real-world entities.
Raster Data Model
Define the world as a regular set of cells in a grid pattern. Represent continuous spatial features or phenomena.
Arcs
Linear features represented as polylines
Node
Starting and endpoints for a line
Vertices
Intermediate points in a line.
Polygon Inclusions
Areas in a polygon that are different from the rest of the polygon but still part of the polygon. Everything is not always homogeneous.
Boundary Generalization
Incomplete representation of boundary locations.
Vector topology
Enforcing strict connectivity and recording adjacency and planarity.
Planar topology
Requires that all features occur on a two-dimensional surface.
Cadastral Data
Property lines/boundaries
Dangles
Lines that do not connect to other lines
cell dimension
defines the size of the cell
delaunay triangles
lines from one triangle do not cross the lines of another. Line crossings are avoided by identifying the convergent circle for a set of three points.
DTM
Digital Terrain Model
Object Data Model
relatively recent alternative for structuring spatial data. Incorporates much of the philosophy of object-oriented programming into a spatial data model. Raises the level of abstraction so that the data objects may be conceptualized and addressed in a more natural way.
logical model
a user’s view of the real objects we portray with GIS. All things of interest and the relationships between them.
inheritance
transferring properties within child classes of objects
bit
each digit or column in a binary number
byte
eight columns or bits are called a ____?
4-byte =’s
32 bits =’s
256 values
one byte
65,536
Two bytes
file pointers / indexes
Link data files
lossless
all information is maintained during compression
lossy
some information is lost in compression
Run-length encoding
compression based on recording sequential runs of raster cell values AAAA = A4
Quad Tree
Raster cells are combined and adjusted within the data layer according to groups of similar areas
Raster Pyramids
Intentionally increase the size of our raster data sets without increasing the resolution to increase display speeds.
.dxf
drawing exchange files, an ASCII or binary file for exchanging spatial data
.dwg
Native binary file used by AutoDesk to serve geographic data and drawings in AutoCAD
.e00
ASCII text file for vector and identifying attibute data (coverage)
tgrxxyyy, stfzz
set of files by U.S. census areas, xx is a state code, yyy is an area code, zz numbers for various file types
.mif, .mid
Map Interchange File, transport from MapInfo
.dem
ASCII text format used to distribute elevation
.cdf
machine-independent data formats for scientific data arrays, common for storing two- and three- dimensional rasters
.opt, .ddf, .dbf
Digital Line Graph data
geodesy
the science of measuring the shape of the earth
map projections
transformation of coordinate locations from the earths curved surface onto flat maps
Earatosthenes
Greek scholar in Egypt who performed one of the earliest well-founded measurements of the Earth’s circumference
Posidonius
Greek scholar, made estimate of the size of the Earth by measuring angles from local vertical (plumb) lines to a star near the horizon
Ellipsoid
Sphere that was slightly flattened at the poles used to modeled the earth shape and size.
semi-major axis
radius in the equatorial direction
semi-minor axis
the radius in the polar direction
geoid
a reference ellipsoid not influenced by the density of the Earth or gravitational pull.
Orthometric height
Distance above the geoid. Height above sea-level/
ellipsoidal/geodetic height
height above an ellipsoid
Geoidal height
Difference between the ellipsoidal height and the geoidal height or height of geoid above the elipsoid
plumb bob
a weight suspended by a string that indicates the direction of gravity
gravimeters
devices that measure gravitational force
GRACE
Twin satellites that measure the strength of gravity and create a reference gravitational surface
ESA GOCE
launched in 2009, uses precision accelerometers to measure gravity-induced velocity changes
Royal Greenwich Observatory
Known as the prime or Greenwich meridian, north-to-south line that is the origin or zero value for longitudes
Magnetic North
is the location towards which a compass points
declination
compass will usually point east or west of geographic north, defining an angular difference in direction to the poles
111.3 Km
degree of longitude separation at the equator
110.6 - 111.7 Km
ground difference for a degree of latitude from equator to poles.
reference frame
well-surveyed points that include an origin or starting point
National Geodetic Survey (NGS)
establishes geodetic latitudes and longitudes of known points which are monumented with a bronze disk, concrete posts or other durable markers
geodetic datums
uses reference points to establish positional measurements in the x,y,z
datum
a reference surface
realization of a datum
specified reference surface plus a physical netowrk of precisely measure points
Terrestrial Reference Frame
Network of precisely measured points.
benchmarks
Precisely surveyed points
triangulation survey
until the mid 1980s this method was commonly used to establish datum points via horizontal surface measurements using a network of interlocking triangles to determine positions at survey stations.
Datum adjustment
position of all points in a reference datum are estimated through a network-wide adjustment
NAD 27
Uses a general least-squares adjustment that included all geodetic surveys completed at that time. Used fixed lat/long of survey station in Kansas.
NAD 83
Included approximately 250,000 stations and 2,000,000 distance measurements using a earth center reference system rather than fixing a station.
High Accuracy Reference Networks (HARNs)
Used precise GPS data to improve accuracy of datums
High Precision Geodetic Networks (HPGN)
another name for HARNs
Continuously Operating Reference Station (CORS)
growing network of satellite observation stations used to improve datum realizations
World Geodetic System of 1984 (WGS84)
set of datums developed by DOD based on dopler satellite measurements, uses a geocentric coordinate system and not widely used outside of the military because they are not tied to a set of broadly accessible, documented physical points. reference coordinate system used by the Global Positioning System (GPS)
GRS80
Ellipsoid that WGS84 and NAD83 datums were based on
International Terrestrial Reference Frames (ITRF) / International Terrestrial Reference System (ITRS)
It is a three-dimensional coordinate system with a well-defined origin (the centre of mass of the Earth) and three orthogonal coordinate axes (X,Y,Z). used to estimate continental drift and crustal deformation by measuring the location and velocity of points.
Datum Shift
Differences between similar datums, that does not imply that points have moved.
Datum Transformation
Estimating the shift and converting geographic coordinates from one datum to another.
Molodenski transformation / Helmert Transformation
Mathematical geocentric datum transformations that are based on a set of parameters
Leveling Surveys
among the oldest methods for establishing a vertical point by establishing height differentials
Spirit Leveling
Horizontal rods were placed between succeeding leveling posts across the landscape to physically measure height differences
trigonometric leveling
Uses optical instruments and trigonometry to measure changes in height.
National Geodetic Vertical Datum of 1929 (NGVD29)
First continental vertical datum in North America
North American Vertical Datum of 1988 (NAVD88)
Fixed to only one tidal station in the town of Rimouski, Quebec and includes over 600,000 KMs of control leveling
Dynamic Heights
Measure the change in gravitational pull from a given equipotential surface.Important for water levels and flows across elevations such as a lake.
Equipotential surface
Pull of gravity is at some specified level. Water spreads out to level across this surface absent wind, waves and other factors.
Map Projection
Is a systematic rendering of locations from the curved Earth surface onto a flat map surface.
Great Circle Distances
Measured on the ellipsoid and in a plane through the Earth’s center. Splits the spheroid into two equal halves. Also used to approximate the distance distortion.
Developable Surface
Geometric shape onto which the Earth Surface locations are projected. (cones, surfaces, planes)
azimuthal projection
planar and often tangent to the ellipsoid at one point
conic projection
cone
cylindrical projection
cylinder
grid north
direction of Y axis in a projection
Lamber Conformal Conic
a cone intersecting the surface along two arcs typically parallels of latitude. Low distortion along east-west band between standard parallels
Standard Parallels
lines that intersect a given projection with no distortion along the plane
Transverse Mercator
Uses horizontal Cylinder, that commonly intersects the Earth ellipsoid along a single north-south tangent along two secant lines
Secant Lines
lines of true scale
central meridian
a line parallel to and the midway point between secants
State Plane Coordinate System
specifies positions in Cartesian coordinate systems for each state to limit distortion
international foot
.3048 meters
Universal Transverse Mercator
standard coordinate system based on the transverse Mercator Projection and divides Earth into 6 degree zoneswide in longitude and extend from 80 degrees south to 84 degrees north. 1 to 60 in an easterly direction starting at longitude 180 degrees
northings
Y values
eastings
X values that increase in an easterly direction
false northings
South UTM zones
Goode Homolosine
interrupted projection used to reduce distortion
Public Land Survey System
Standardized system for designating and describing the location of land parcels developed to remedy the shorts of metes and bounds surveying
metes and bounds
describe a parcel relative to features on the landscape sometimes supplemented with angle or distance measurements
digitizing
the process of collecting digital coordinates by converting data into a digital format
neatline
used to provide a frame around all map elements
graticle
set of coordinate lines that represent lat long
grid
set of constant x and y coordinates
cartometric maps
those that faithfully represent the relative position of objects and thus may be a suitable source for spatial data.
feature maps
among the simplest maps because they map points lines or areas and provide nominal information
Choropleth maps
depict quantitative information for areas
Dot-density maps
used to show quantitative data where dots are placed to equal a total value.
Isopleth maps
displays equal values using lines or ranges of similar values.
map generalization
the unavoidable approximation of real features when they are represented on a map
feature generalization
is a modification of features when representing them on a map
fused - generalization
multiple feature may be grouped to forma larger feature
simplified - generalization
boundary or shpae details are lost or “rounded off”
Displaced - generalization
features may be offset to prevent overlap or to provide a standard distance between mapping symbols
Omitted - generalization
small features in a group may be excluded froma map
Exaggerated - generalization
standard symbol sizes are chosen which when scaled do not represent true dimensions
registration
is the conversion of digitizer or other coordinate data to an earth-surface coordinate system.
Manual Digitization
is human-guided coordinate capture from a maps or image source
on-screen digitizing (heads up)
involved manually digitizing on a computer screen, using a digital image as a backdrop
hardcopy digitizing
human guided coordiante capture from a paper, plastic or other hardcopy map.
starting node
starting point along a line
ending node
end point along a line
point mode - digitizing
where the operator must depress a button or otherwise signal to the computer to sample each point
stream mode - digitizing
where points are automatically sampled at a fixed time or distance frequency.
Minimum distance - digitizing
Point is not recorded unless it is more than some minimum threshold distance
Undershoots
digitizing error where nodes do not quite reach the line or another node
Overshoots
digitize error where lines cross over existing nodes or lines
node snapping / line snapping
used to reduce undershoots and overshoots while digitizing
snap tolerance/snap distance
minimum distance allowed between features
Spline: line smoothing
smoothly interpolate curves between digitized points and densify the set of vertices used to represent a line
“weed” distance
point thinning method that weeds out redundant line points
Lang method
a pre-determined number of vertices is spanned and simplification occurs.
scan digitization / skeletonizing
scanned lines are converted to a vector data format
rubbershheting
involves fitting a local equation to adjust the coordinates of features
coordinate transformation / registration
brings spatial data into an Earth-based map coordinate system so that each data layer aligns with every other data layer typically employs a statistically-fit linear equation.
control points
used to transform the digitized data from the digitizer or photo coordinate system to a map-projected coordinate system.
Affine coordinate transformation
employs linear equations to calculate map coordinates usually fit using a statistical method that minimizes the root mean square error. Most commonly applied coordinate transformation.
RMSE
average error that provides an index of accuracy.
resampling
involves reassigning the cell values when changing raster coordinates or geometry
nearest neighbor - resampling
taking the output layer value from the nearest input layer
bilinear interpolation - resampling
distance based averaging of the four nearest cells
cubic convolution - resampling
a weighted average of the sixteen nearest cells
Global Navigation Satellite Systems (GNSS)
satellite-based technologies that give precise positional information
NAVSTAR
GPS - the first deployed and is the most widely used system.
GLONASS
Russian system user internationally
Galileo
developed by a consortium of European governments and industries
Chinese Satellite Navigation Ssytem
Compass - Chinese full constelation GNSS
satellite segment - GNSS
a constellation of satellites orbitting the earth and transmitting positioning signrals
control segment - GNSS
consists of the tracking, communications, data gathering, integration, analysis and control facilities
user segment - GNSS
the set of individuals with one or more receivers
carrier signals - GNSS
L1 and L2 - modulated to produce two coded signals.
pseudo-random cocde
(C/A, P, and M) appear quire similar to noise but provide position information.
almanac - GNSS
data used to determine the status of satellites in the GPS constellation.
ephemeris data
allow a GPS receiver to accurately calcuate the position of the broadcaseing satellite and the expected positions of other satellites.
ranged distances - GNSS
determined distance from the carrier and coded signals to determien distance between two objects.
Ionospheric and atmospheric delays
major sources of GNSS positional error.
dual frequency receivers - GNSS
collect information on multiple GNSS signals simultaneously and use sophisticated physical models to remove most of the ionospheric errors. No good ways to remove atmospheric effects.
Multipath signals
Signals that have reflected off objects prior to reaching the antenna
dilution of precision or DOP
Satellite geometry is summarized in this number
PDOP Positional Dilution of Precision
most used and is the ratio of the volume of a tetrahedron created by the four most widespread, observed satellites to the volume defined by the ideal tetrahedron. Lower PDOP creates small area of uncertainty
differential positioning
an alternative method that employs tow or more receivers to remove most of the range errors and thus greatly improving the accuracy of GNSS positional measurements
base station - GNSS
used in differential GNSS positioning to establish a true coordinate location to estimate the range of measurement error for each position fix.
real time differential correction
Requires extra equipment, but provides real-time differential corrections.
Wide Area Augmentation System (WAAS)
Administered by the U.S. Federal aviation administration to provide accurate, dependable aircraft navigation. provides real-time accuracy from single fixes using network of ground referenced stations spread across north america.
real-time kinematic (RTK)
Dual frequency carrier phase position correction technique.
remotely sensed data
Data recorded at a distance
large area coverage
Data that captures a large area in a uniform manner
extended spectral range
Light from wavelengths outside the range of human eyesight
geometric accuracy
Aerial images contain geometric distortion due to imperfections in the camera, lens, or film systems or due to camera tilt or terrain variation in the target area
permanent record
An image is fixed in time so the conditions at that time are locked into place.
electromagnetic spectrum
Full range of wavelengths
active radar systesm
Generate an energy signal and detect the energy returned
Radar (radio detection and ranging)
Most common active remote sensing system
photogrammetry
a profession concerned with producing precise measurements of objects from photographs and photoimagery
diaphragm
Mechanism to control the amount of light reaching sensing media digital sensor or file that records light
optical axis
Central direction of the incoming image and it is precisely oriented to intersect the sensor in a perpendicular direction.
focal plane
Where images are recorded on a flat state perpendicular to the optical axis
image scale
Relative distance on the image to the corresponding distance on the ground.
image resolution
Smallest object that can reliably be detected on the image
perspective views
pass through a single point at the center of the camera lens and give a geometrically distorted image of the earths surface that most aerial image provide the user
Web Mapping Service (WMS)
Standard way of serving geographic data over the internet
Database Management System (DBMS)
Specialized computer program for organizing and manipulating data
Data Independence
Allows us to make changes in the database structure in ways that are transparent to any use or program. Restructuring the database does not require a user or programmer to modify their procedures
Type - DBMS
Integer, text, double - DBMS
Entity - DBMS
Collection of related data items that are treated as a unit
Instance - DBMS
Specific entity
record - DBMS
Row or line in a table
tuple - DBSMS
Another name for a row in a relational table
multi-tiered architecture
Seperation of data and functions into multiple levels
Transaction Manager
component of a database management systems that processes requestes from clients and passes them to a server
Schema - DBMS
conceptual structure of a database
Relational Algebra
Takes relations (tables) as input and returns relations as output using combines or split tables to generate subset of expanded tables.
Distributed database systems
maintains multiple data files across different sites on a computer network.
Spatial Scope
Extent or area of the input data that are used in determining the values at output locations.
Local Operations
Use only the data at one input location to determine the value at a corresponding output location.
Neighborhood Operations
Use data from both an input location pluys nearby locations to determine the output value
Global Operations
Use data values from the entire input layer to determine each output value
On-screen query
Data layer is displayed and features are selected by a human operator
Set Algebra
Uses , =, and <>
Boolean Algebra
OR, AND, and NOT
Binary Classification
0 and 1, True and False, A and B or some other two-level classification
Natural Breask
Looks for obvious gaps in the the data.
Zoning Effect - MAUP
aggregate statistics may change by the shape of the units
Size Effect - MAUP
aggregate statistics may change with the area of the units.
Dissolve
primarily used to combine similar features within a data layer
Proximity Functions
Operations that hinge on proximity, the distance betweenfeatures of interest
Simple Buffering
fixed distance buffering that identifies areas that are a fixed distnace or greater from a set of input features overalap is dissolved
Compound Buffering
Maintain all overlapping boundaeries
Nested Buffering
Creates buffers at multiple distances
Variable distance buffers
Buffer distance is variable and may change among features
Clip
considered a cookie cutter overal where bounding polygon layer is used to define the areas for which features will be output
Intersection
overlay that combines data from both ayers but only for the region where both layers contain data
Union
overlay that includes all data from both the bounding and data layers
centers
set of connected features in a network that connect to at least one and possibly many network links
transit cost
reflects the price one pays to move a resource hrough a segment of the netwrok
Resource Allocation
apportionment fo a netwrok to centers
Kernal
Moving window used in raster analysis
Edge detection
based on comparing differences across a kernel where values on one side of the kernel are subtracted from values on the other side
high pass filters
accentuate differences between neighboor cells
sptaial covariance
determines how similar or disimilar neighbor cells are from one another
friction surface
cell values represetn the cost per unit travel distance fro crossing each cell
spatial interpolation
prediction of variables at unmeasured loctation based on sampling at known locations
sptatial predection
involves estimation of variables by using multiple variable to better predicte values.
Nearest Neighbor (Interpolation)
Thiessen polygon interpolation based on nearest smaple locations
exact interpolator
interpolated surface equals the smaple values at each sampel point
fixed radius
defines the size of a circle that is centered on each cell that is used to determine a local average based on values within the circle radius
Inverse Distance Weighting
estimates the value at unknown points using the sampled values and distnace to nearby known points.
Spline
flexible ruler that creates a smooth surface through a set of points
spatial autocorreclation
tendency of nearby objects to vary in unison.
cross-correlation
Similar trends between different variables
Kriging
statisticall-based estimator where weights are chosen in a statistically optimal fashion.
convex hull
is the smallest poluygon created by edges that completely enclose a set of poitns for which all exterior angles between edgest are greater than or equal to 190 degrees
kernal mapping
uses a set of sample locations to estimate a continous density surface
accuracy
the nearness of an observation or estimate to the true value
adaptive sampling
a method to increase sampling efficiency by increasing the sptaitla sample frequency in areas with higher spatial variability
affine coordinate transformation
a set of linear equations used to transform from one cartesian coordinate system to another. The transformation applies a scaling, translationa nd roatation
Arc
a line usually defined by a sequence of coordinate points
ASCII
American Standard Code for INformation Interchange. a Set of numbers associated witha symbol used in information storage and processing
AVHRR
Advanced Very High Resolution Radiometer used to collect visible, thermal and infrared satellite imagers of the glove each data
beacon reciver
A GNSS reciever capable of decoding beacon base sattion signals transmitted by the U.S. coast Guard beacon stations
bearing
a direction usual specified as a geographic angle measured from some base lines
bilinear interpolation
a method for calculating values for a grid location based on a linear combination of nearyb grid values
BIT
A binary digit. A bit has one of two values, or or off, zero or one. This is the smallest unit of digital information storage and the basic building block from which all other computer data and programs are represented
bundle adjustment
the simultaneous removal of geometric distortionand production of orthophotographs froma number of aerial images
byte
a unit of computer storage consisting of 8 binary digits. EAch binary digit may hold a zero or a one A byte may store up to 256 different values
C/A code GPS
Coarse acqusition code, a GPS signal used to make fro rapid, relatively low-accuracy positional estimates. Accuracies whtout further corrections are typically from a few to tens of meters
Carrier-phase GPS
Relatively slow but accuracte signal used to estimate position Positons may be determiend to within a few centeimetsers of rbeter
Cartesian Coordinate System
Right angle two or three-dimensional coordinate system
cartographic object
a digital representationof a real-world entity
cartometric map
a map produced such that the relative positonso of objects depicted are spatially accuract, within the limits of the technology and the map projection used
centroid
the point with the lowest average distance to all points that define the area boundary
clients
programs that request data from a aserver
cluser smapleing
a technique of grouping samples to reduce travel time among samples while maintianig sample number
COGO
coordinate geometry, the entry of spatial data via coordiate pairs usually obtained from field surveying instruments
conformal projection
wjhen it preserves shape for some portions fo the map
conformal coordinate transformation
a registration that requires scale changes to be equal inthe x and y directiosn
converget circl
a circle used in definign facet for a TIN, that passes through three points, and does not ccontain any other points
coordinate transformation
conversion or assignment of coordiantes from a non=projected coordinate system to a coordinate system, typically via a system of linera mathematical equations
cubic convolution
method of calculating grid values based on a weighted combintation of 16 nearby grid cells
datum adjustment
a re=calculation of a datum based on additional measurements
datum shift
change in horizontal or vertical point locations that result froma datum adjustment
electromagnetic spectrum
a range of energy wavelengths, from x-rays through radar wavelengths
endlap
end to end overlap in aerial photographs taken in the same flight line
entity
a real world item or phenomenon that is represetned ina GIS system or database
epsilon band
band surrounding a linear feature that describes the positional error lreative to the feature location
fiducial amrks
marks that are recorded near the edges of aerial images andused to remove systematic camera distoriton and to register images
geocentric
a measurement system that uses the center of the Earth as the origin
helmert transformation
is a transformation method within a three-dimensional space. It is frequently used in geodesy to produce distortion-free transformations from one datum to another. The Helmert transformation is also called a seven-parameter transformation and is a similarity transformation
hypsogrpahy
representation of height features
Law of Sines
trigonometric relationship that allows the calculation of unknown triangle edge lengths from known angles and edge lengths
LIS
land information system, name originally applied for GIS systems specifically developed fro proeprty ownership and boudnary records managemetn
local operation
a spatial operation where the output location, area, or extent comes from operations on the same extent
meridian
line of constantlongitude
minimum mapping unit
smallest area resolved when interpreting an aerial or satellite image
Molodenski Transformation
zero rotations and a scale of unity, but converts directly from geodetic coordinates to geodetic coordinates, without the intermediate shifts to and from cartesian geocentric coordinates, associated with the Helmert transformation. The Molodensky transformation is simple to implement and to parameterize, requiring only the 3 shifts between the input and output frame, and the corresponding differences between the semimajor axes and flattening parameters of the reference ellipsoids.
Nadir point
point directly belwo the aircraft usually near the center of an aerial image
N-Tuple
a group of attribute values in a database management systems
Orthogonal
intersecting at a 90 degree angle
Parallax
relative shift in positon of features due to a shift in viewing location
perspective convergence
apparent decrease in inter-object distance as the objects are farther away
plan curvature
terrain curvatue along a contour
range pole
used in srveying to raise a GNSS antenna bove groudn surface
secant lines
lines of intersection between a developable surface and a spheroid in a map projection
semivariance
variance between values sampled at a given lag distance apart
spaghetti data model
vecotr data model in which lines may cross without intersecting
traverse
series of survey stations spanning a survey. traverses are clsoed when the return to the starting point and open when they do not
terrestrial reference frame
set of measured points and their calculated coordinates that are used to define a geodetic datum
Unary operation
an operation that has only one inpu
zenith angle
angle measured between a vertical line upward from a point on the Earth and the line from that point to the sun.
Internal Direction
Where an object is located inside of the reference object
External Direction
Where an object is located outside of thte reference object
Spatio-temporal Models
Time passes explicitly within the running of the model and changes time-driven processes within the model
Cellular Automata
one of a set of units in a mathematical model that have simple rules governing their replication and destruction. They are used to model complex systems composed of simple units such as living things or parallel processors.
Agent Based Models
Systems contain agents that may move across digital landscapes and react to the environment or other agents according toa small set of pre-sepecified rules
Field Based Model
Uses fields to organize data
Geometric Networks
series of interconnected features built within a feature dataset that provide data sources for network junctions and edges (network features). Uses concepts similar to graph theory.
Locational fallacy
error related to spatial characterizations. Can be too simplistic or even wrong.
Atomic Fallacy
errors due to treating elements as separate atoms outside their spatial context
ecological fallacy
errors due to performing analyses on aggregate data when trying to reach conclusions on individual units
First (direct) geodetic problem
Given a point, direction and distance from a second point find the second point.
Second (inverse) geodetic problem
Given two points, determine the azimuth and length of the line that connects them.
Nadir
The given point is the local vertical direction pointing in the direction of the force of gravity at that location. Direction opposite is the Zenith.
celestial horizon
line or circle that forms the apparent boundary between earth and sky
topocentric coordinates
celestial coordinate system that uses the observer’s local horizon as the fundamental plane.
North Celestial pole
point in the sky about which all the stars seen from the Northern Hemisphere rotate. North star is almost in this exact point.
celestial equator
great circle of the imaginary celestial sphere on the same plane as the equator of Earth that tilts north or south depending on the observers location.
Meridian Plane
Any plane perpendicular to the celestial equator and containing the celestial poles
Local Meridian
the plane containing the direction to the zenith and the direction to the celestial pole.
horizontal datum
model of the earth as a spheroid (includes a reference ellipsoid and set of survey points).
azimuthal Equidistant
planar (tangent) - used for air route distances - distances measured from the center are true - distortion of other properties increases away from the center point
Cylindrical equal-area projections
preserves area, shape and distance gets distorted near the upper and lower regions of the map - straight meridians and parallels - meridians are equally spaced and the parallels are unequally spaced
Conic projections
preserves directions and areas in limited areas - distorts distances and scale except along standard parallels - generated by projecting a spherical surface onto a cone
Extent: Broad in East-West
use a conical projection
Broad in North-South
use a transverse-case cylindrical projection
Latitude: Low-latitude areas
use a conical projection;
Polar regions use a
azimuthal planar projection
dasymetric map
alternative to choropleth maps. ancillary information is used to model internal distribution of the mapped phenomenon.
Multivariate displays
putting more than two sets of data on one map.
Profile
A well-defined subset of SDTS created fro translating a specific type or model of spatial data with as few SDTS options as possible.
CADD
Computer-Aided Design and Drafting
Translators
take data structured under a source schema and transofrm it into data structured under a target schema. So the hat the target data is an accurate representation of the source data.
Standard Interchange Format
geospatail data excahnge format used to move graphics files between DOD project 2851 and currently codified in Content Standad for Digital Geospatial Metadata maintained by the FGDC.
Data Owner/Creator
Creates tables, feature classes and owns those datasets
Administrator
Full control of the databsae, can read, create, update, delete features.
Editor / Read/Write
Can Read, update, create and delete features. SELECT, INSERT, UPDATE and DELETE
Reader Only / Data Viewer
Can only view data and use SELECT functions
Operating System Authentication
indicates a user logs in to the computer and the credentials for authorization are supplied to the database by the OS of the user’s computer (log in once)
Database Authentication
Users log in to the server and then must separately log into the database.
Validation
automatic computer check to ensure that the data entered is sensible and reasonable
Verification
testing the database to confirm whether data has been processed correctly or not.
Authorization
Setting permissions to various parts of the database
Database Auditing
Tracking who did what with the database
System Architecture / strategic bluepring
conceptual design that defines the structure and/or behavior of a system. Can be thought of as a To Be Created system.
Viewpoints
Address the needs of various roles within system architecture
Enterprise Software
Collection of computer programs with common business applications, tools for modeling how the entire organization works and development tools for building applications unique to the organization.
Enterprise Networking
integration of disparate networks and systems and managing them, and planning for additional changes.
application server
software framework that provides both facilities to create web applications and a server environment to run them
database server
server which houses a database application that provides database servers to other computer programs or to computers
Descriptive Statistics
Analysis of data that helps describe, show or summarize data in a meaningful way. They do no allow us to make conclusions beyond the data we have analysed or reach conclusions. Simply a way to describe our data. Provide information about our immediate group of data.
Summary Statistics
Give a quick and simple description of the data, can include mean, median, mode, minimum, maximum, range, std deviation, etc.
Coefficient of determiniation
R Squared indicates how well data fit a statistical model.
theodolite
precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes
level machine
optical instrument used to establish or verify points in the same horizontal plane.
total station
an electronic/optical instrument used for surveying and includes an electronic transit theodolite integrated with electronic distance measurement (EDM) to measure both vertical and horizontal angles and the slope distance from the instrument to a particular point, also includes an on-board computer to collect data and perform triangulation calcultations
geomatics
science and technology of gathering analyzing interpreting distributing and using geographic information. encompasses a broad range of disciplines, cartography surveying mapping remote sensing and GIS and GPS
Quality Assurance
Planned and systematic production processes that provide confidence in a products suitability for its intended purpose
Quality Control
product oriented and focuses on defect identification
Spatial Data Standards
Methods for structuring, describing and elivering sptaitally reference data
Interpoperability standards
identify how spatial data are served between heterogeneous networks of software systesm
conceptual schema
determine where dependency is within the data (relationships and connections)
logical data structure
arrange data into a logical structure which can then be mapped into the storage objects supported by the database management system. (object-based)
views
results set of a stored query on the data which the database users can query. Not part of the physical schema.
sequences
ordered collection of objects in which repetitions are allowed, number of elements is called the length of the sequence
synonyms
an alias or alternate name for a table, view, sequence or other schema object. Makes user access easier
procedures
subroutine available to applications that access a relational database system
database trigger
procedural code that is automatically executed in response to certain events on a particular table or view in a database
subroutines
sequence of program instructions that perform a specific task, packaged as a unit.
database cluster
collection of databases that is managed by a single instance of a running database server.
section (coverage)
arc or portion of an arc used to define a route or the building blocks of routes
region
collection of one or more contiguous or noncontiguouse polygons defining a geographic feature
tic
geographic reference or control point used for geograhic registrationand control for digitizing
coverage extent
minimum bounding rectangle that defines the coordinate limits.
3 types of resolution
spatial, spectral, temporal
CSDGM
Content Standard for Digital Geosptaial Metadata
OGC
Open Geospatial Consortium - ad-hoc self-selected
FGDC
Federal Geographic Data Committee
NSDI
National Spatial Data Infrastrucutre - what the FGDC focuses on.
Integrity Constraints
set of formulas imposed on a database that prescribes a database schema
Database design
process of producing a detailed data model of a database and contains all the needed logical and physical design choices and physical storage parameters needed to generate a design in a data definition language.
Inferential Statistics
Sample strategies that allow us to use samples to make generalizations about the populations from which samples were drawn.
Spatial resolution
Refers to the number of pixels utilized in the construction of a digital image. A higher spatial resolution means more pixels.
Temporal resolution
Precision of a measurement with respect to time
Heisenberg’s uncertainty principle
trade off between temporal resolution and measurement of its spatial resolution.
Spectral Resolution
is the width of the regions of the electromagnetic spectrum that a sensor will detect
absolute scale
system of measurement that begins at a minimum or zero point and progresses in only one direction.
abstract data
what we draw on maps but isn’t there (political boundaries)
1 mi. = how many feet
5280 ft
1 mi = how many km’s
1.6093 kms
minutes of arc in one degree
60 minutes
seconds of arc in a minute
60 seconds
radians
360 is a whole circle - 2pi x radius is the circle
Azimuth
angle between 0 and 360 measured clockwise from north
bearings
angle less than 90 within a quadrant defined by the cardinal directions E.g. S 45 W in bottom left quadrant.
short integer
(2 bytes) numerica vavlues without fractional values between -32768 and 32768
long integer
(size 4 bytes) numeric values without fractional values between -2147483648 and 2147483647
float
(size 4 bytes) numeric values with fractional values
double
(8 bytes) numeric values with fractional values
precision field attribute
number of digits allowed within the field
scale field attribute
number of decimals within the number
interoperability standards
identify how spatial data are served between heterogeneous networks of software and hardware systems.
Building blocks of a network
Edges, Junctions and Turns
Geometric Networks are comprised of …
Edges and Junctions
Component GIS Software
seeks to build software applications that meet a specific purpose and thus are limited in their spatial analysis capabilities.
Utilities
stand-alone programs that perform a specific function. For example, a file format utility that converts from on type of GIS file to another.
Inductive Reasoning
makes broad generalizations from specific observations.
Deductive Reasoning
starts out with a general statement, or hypothesis, and examines the possibilities to reach a specific, logical conclusion. moves from the general to the specific
Abductive Reasoning
usually starts with an incomplete set of observations and proceeds to the likeliest possible explanation for the group of observations
TIGER
Topologically Integrated Geographic Encoding and Referencing (TIGER) database
.xml
file that stores metadata | Extensible Markup Language
logical consistency
compliance with topological rules
validity
the degree to which a data set is fit for use in a particular application
Systematic Errors
tend to be consistent in magnitude and/or direction
Additive correction
involves adding or subtracting a constant adjustment factor to each measurement
Proportional Correction
involves multiplying the measurement(s) by a constant.
Control network accuracy standards used for U.S. National Spatial Reference System
must be in 95% confidence limit, less than 10% of total
Trilateration
alternative to triangulation that relies solely on distance measurements where the interior angles of a triangle can be determined if the lengths of all three triangle sides are known
National Spatial Reference System (NSRS)
A national geodetic control network maintained by the National Geodetic Survey
orthoimage
has the same metric properties as a map and has a uniform scale, corrected for scale changes
nominal scale
is equivalent to f / H, where f is the focal length of the camera (the distance between the camera lens and the film – usually six inches), and H is the flying height of the aircraft above the ground.
planimetric view
looks as though every position on the ground is being viewed from directly above. In plan views, scale is everywhere consistent.
relief displacement
The effect of continuously-varying scale is to distort the geometry of the aerial photo
1 degree DEMS are
3 arc seconds
30 minute DEMs are
2 arc seconds
1/3 arc second
approximately 10 m
1/9 arc second
approximately 3 m
1 arc second
approximately 30 m
1 radian
57.29 degrees
180 degrees
3.14 radians
EPSG
structured dataset of CRS and Coordinate Transformations, originally compiled by the no defunct Eurpoean Petroleum Survey Group
EPSG 4326
WGS84 Commonly used by organizations that provide GIS data for the entire globe CRS used by google earth
EPSG 4269
NAD83 - Most commonly used by US agencies
EPSG 4267
NAD27
EPSG 32610
Projected Easting/Northing for UTM ZONE 10
EPSG 3857
Web Mercator Tiles from google maps, open street maps
mass points
Spot elevations produced photogrammetrically
breaklines
spot elevations collected along linear features
primary key
consists of one or more columns whose data contained within is used to uniquely identify each row in the table.
foreign key
is a set of one or more columns in a table that refers to the primary key in another table.
topology
shape-invariant spatial properties of line or area features such as adjacency, contiguity, and connectedness, often recorded in a set of related tables.
topological
maintains topology
topographic
arrangement of the physical features of an area
topography
study of the shape and features of land surfaces
toponym
general name for any place or geogrpahical entity.
topologically
maintains topology
Kanban
Visualize Work. By creating a visual model of your work and workflow, you can observe the flow of work moving through your Kanban system. Making the work visible—along with blockers, bottlenecks and queues—instantly leads to increased communication and collaboration.
Agile
group of software development methodologies based on iterative development, requirements and solutions evolve through collaboration between self-organizing cross-functional teams. Rather than creating tasks and schedules, all time is “time-boxed” into phases called “sprints.”
Waterfall
sequential linear process of project management
Extreme Programming
as a type of agile software development it advocates for frequent releases in short development cycles, which is intended to improve productivity and introduce checkpoints at which new customer requirements can be adopted.
Project Management Plan (PMP)
formal approved document that defines how the project is executed, monitored, and controlled. Project Goals. ... Project Scope. ... Milestones and Major Deliverables. ... Work Breakdown Structure. ... Budget. ... Human Resources Plan. ... Risk Management Plan.
Rational Unified Process (RUP)
iterative software development process framework based on phases of development and four building blocks (Who, How, What and When) and four life cycles (inception, elaboration, construction and transition phase).
Construction design Methodology (CDM)
the planned method of construction, taking into account all contractual and legal requirements, construction constraints, risks, and opportunities. Methodology includes the temporary and permanent works and the services required to complete the construction works.
software development life cycle (SDLC)
core aspect of software engineering is the subdivision of the development process into a series of phases, or steps, each of which focuses on one aspect of the development
server
manages access to a centralized resource or service in a network.
Print (python)
write to screen
tags
opening or closing used ot makr the start or end of an element
element
consists of an opening tag its attributes any content and a closing tag.
GML:
language used to encode geogrpahic content for any application, by describing a spectrum of application object s and their properties
KML
language for the visualization of geographic information tailored for Google Earth. Renders and stylizes GML data. First and formeost a 3D portrayal transport, not a data exchange transport.
passive remote sensing
use energy generated by the sun and reflected off of the target objects
IFOV
instantaneous field of view that corresponds to the size of the area viewed by satellite image
SPOT
first satellite system designed to serve commercial interests in a high-volume production mode
Discrete Return LiDAR
system records specific values for each laser pulse down
Waveform LiDAR
collects a continuous record of the pulse returns
passive optical systems
based on reflected incident radiation
UAV
just the aircraft itself
UAS
all encompassing term for everything that makes a drone/UAV operate, the ground control station with pilot, communications, support equipment etc.
Ssytem Architecture and Design Implementation Strategy
Requirements Phase, Design Phase, Construction Phase, Implementation Phase, Capacity Planning Tools
weighted overlay
Reclassifies values in the input rasters into a common evaluation scale of suitability or preference, risk, or some similarly unifying scale
reconciling
Applying changes to the default database in a versioned database environment is called?
quantile
equal number of features in each class
xml parser
tool which can compare XML document against its described schema
geoid separation (N) or geoid undulation
deviation between the geoid and an ellipsoid
global statistics
identify and measure the pattern of the entire stuyd area
local statistics
identify variation across the study area
Anselin Local Moran’s I
local statistic measures strength of patterns for each specific feature HH LL HL LH
Getis-Ord General G
Global Statistic that indicates whether similar values are clustered
Hot Spot analysis (Getis-Ord Gi*)
Local version of Getis-Ord that indicates hot or cold spots
Ordinary Least Squares
Regression technique
Geographically weighted Regression
Regional variation incorporated into regression model
application scheme
created to limit XML schema to a specific domain of interest
subset tool
used to generate GML profiles containing a user-specified list of components
GML features
an application object that represents a physical entity and may not have geometric aspects.
GML geometry objects
defines a location or region instead of a physical entity
Synthetic Aperture Radar
Pulses of radio wavelengths
Radiometric Resolution
sensitivity of sensor to collect very slight differences in emitted or reflected energy
NVDI
(NIR-red)/(NIR+red)
GPS polygon and line data collection rate
5-second interval
GPS point data collection rate
1-second interval
append
multiple input datasets into an existing target dataset
errors of omission
a mistake that consists of not doing something you should have done
errors of commission
mistake that consists of doing something wrong
merge
combines multiple input datasets into a new dataset
radial distortion
radial from the principle point and cause an image to appear either closer or further from the principle point and are most serious near the edges
Identify
Computes a geometric intersection of the input features and identity features. The input features or portions thereof that overlap identity features will get the attributes of those identity feature
Symmetrical difference
Features or portions of features in the input and update features that do not overlap will be written to the output feature class.
Update
Computes a geometric intersection of the Input Features and Update Features. The attributes and geometry of the input features are updated by the update features in the output feature class.
relative scale
system of measurement that begins at a point selected by a person and can progress in both directions
multidimesnional attributes
data compreissed of multiple dimensions sucha s space time
ETL (Extract, Transform, Load)
A function that performs data extraction, transformation, and loading. Data is extracted from different sources that have different formats, so data must be transformed (or “cleansed”) before loading.
Disjoint
a Ո b = ᴓ
Topologically Equal
a = b
Intersects
a Ո b ≠ ᴓ
Contains (feature b is within a)
a Ո b = b
Within (a is within b)
a Ո b = a
tesselations
connected networks that partition space into a set of sub-aresas
