Term
|
Definition
a collection of facts or figures that pertain to places, people, things, events, concepts |
|
|
Term
|
Definition
processed or value added data that have certain perceived values to a user or a community of users |
|
|
Term
|
Definition
transformation of data into information is an explicit act by a user to raise their ___ to a level appropriate for specific decision making purposes |
|
|
Term
|
Definition
When a user deploys knowledge to perceive relationships, formulate principles, and introduce personal values |
|
|
Term
|
Definition
1. formed or constructed to achieve certain basic objectives or functions
2. their continuing existence depends on their ability to satisfy the intended objectives-if this ability fails or starts to decline, systems concerned must be upgraded or replaced
3. individual system is composed of many interrelated parts which may be operational systems by themselves
4. these parts operate individually and interact with one another according to certain rules of conduct such as procedures, laws, contractual agreements, and accepted behavior |
|
|
Term
|
Definition
1. is set up to achieve the specific objectives of collecting, storing, analyzing, and presenting information in a systematic manner.
2. structurally is made up of interrelated components that include a combination of data and technical and human resources
3. being made up of input, processing, and output systems, all working according to a well-defined set of operational procedures and protocols.
4. can be operated independently and at the same time linked with other information systems |
|
|
Term
Information System Network |
|
Definition
- The data and technical and human resources used to form the system
- communications protocol and data management procedure
- functional subsystems
- stand-alone or network mode of systems or network mode of systems configurations
|
|
|
Term
Nonspatial Information systems |
|
Definition
those designed for processing data that are not referenced to any position in geographic space. For example, a system for accounting. |
|
|
Term
Spatial Information Systems |
|
Definition
those designed for processing data pertaining to real-world features or phenomena that are described in terms of locations |
|
|
Term
True/False
All Spatial information systems can be regarded as GIS |
|
Definition
False
CAD systems, CAM systems are also spatial information systems |
|
|
Term
True/False
Only those spatial information systems that are ussed for processing and analyzing geospatial data or geographically referenced data can be labeled as a GIS |
|
Definition
|
|
Term
|
Definition
- Characterized by geographic space
- Representation at geographic scale
|
|
|
Term
|
Definition
data are registered to an accepted geographic coordinate system of Earth's system so that data from different sources can be spatially cross referenced |
|
|
Term
|
Definition
data are normally recorded at relatively small scales and must be generalized and symbolized |
|
|
Term
Land Information Systems (LIS)
Land Related Information Systems (LRIS) |
|
Definition
focus of the system on land related activities such as ownership, tax assessment, land and water resources |
|
|
Term
Geographic Information Science |
|
Definition
set of basic research issues raised by the handling of geographic information that include geographic data, problem solving, and using geographic information on society
Aims to provide the theoretical and organizational coherence for the scientific study of geographic information |
|
|
Term
True/False
Canada produced the first ever GIS |
|
Definition
|
|
Term
True/False
GIS was application driven during the 1960's-70's- built to meet specific information needs of individual organizations |
|
Definition
|
|
Term
|
Definition
refers to the spatial relationship of adjacenc, connectivity, and containment among topographic features |
|
|
Term
|
Definition
- solved data representation problem that hindered GIS in the early years
- reduced the complexity of applying geographic data for spatial analysis, thus making GIS easier to use
- geospatial data can be stored in a simple structure that is capable of respresenting their attributes
|
|
|
Term
|
Definition
- created ArcInfo released in 1982
- vector based GIS to use georelational data model that employed hybrid approach to geographic data processing
- graphical data stored using topological data structure, while attribute data are stored using relational or tabular data structure
|
|
|
Term
|
Definition
- shifted to data oriented approach of GIS development fundamentally changed the way GIS technology had been developed
- designed to meet demand of corporate business goals
|
|
|
Term
enterprise Computing environment |
|
Definition
integration of geographic data with other type of business data |
|
|
Term
Information infrastructure |
|
Definition
- emerged in early 1990s when U.S. proposed Nation information Initiative
- intended to provide access to information affecting their lives that pertains to governement, health care, education, and community development
|
|
|
Term
Location Based Service (LBS) |
|
Definition
LBS makes use of the information about the location of the mobile computer to deliver personalized, localized, and real time geographic services to the user. |
|
|
Term
|
Definition
enhanced 911 capable of identifying the location of the user in case of emergency |
|
|
Term
|
Definition
traffic information, navigation assistance, yellow pages, and travel/tourism information |
|
|
Term
|
Definition
vehicle tracking, logistic planning, utility asset inspection and management |
|
|
Term
|
Definition
delivery of local news, weather report, and forecast, driving directions |
|
|
Term
|
Definition
using GPS technology to obtain real time location information to provide driving directions and vehicle tracking functionality in fleet management |
|
|
Term
triggered location services |
|
Definition
including location senstive advertising, billing, and logistics |
|
|
Term
|
Definition
obtaining location based information by means of coordinates |
|
|
Term
|
Definition
- data
- technology
- application
- people
|
|
|
Term
|
Definition
can be categorized into
- geodetic control network
- topographic base
- graphical overlays
|
|
|
Term
|
Definition
- foundation of all geographic data
- provides goegraphical framework by which different sets of geospatial data can be spatially cross-referenced with another
- established by high-precision surveying methods and vigorous computation at the national or contintal level.
|
|
|
Term
|
Definition
created as the result of a basic mapping program by national state/ provincial, and local government mapping agencies
land surveying and phtogrammetry |
|
|
Term
|
Definition
- thematic data pertaining to specific GIS applications
- overlays of physical features can be derived directly from the topographic base
- can be collected by site investigation
|
|
|
Term
|
Definition
data that depict the real world by means of discrete points, lines, and polygons |
|
|
Term
|
Definition
Data depict the real world by means of a grid of cells with spectral or attribute values
not good for representing individually identifiable features but is ideal for a variety of spatial analysis functions |
|
|
Term
|
Definition
depict the real world by means of a set of selected points or continuous lines of equal vales and can be analyzed and displayed in two or three dimensions and are most suited for natural phenomena |
|
|
Term
|
Definition
can be formed by aggregating one or more geodatabases, usually organized into broad categories such as land use, transportation, hydrology, environment, and utility |
|
|
Term
|
Definition
made up of a configuration of core and peripheral equipment that is used for the acquisition, storage, analysis, and display of geographic information. |
|
|
Term
Central Processing Unit (CPU) |
|
Definition
perfoms all the data processing and analysis tasks and controls the input/output connectivity with data aquisition, storage, and display systems |
|
|
Term
|
Definition
were developed as tand alone applications that ran on a single host computer, but todays GIS are mostly implemented in a network environment using the client/server model. |
|
|
Term
|
Definition
the computer on which the data and software aer stored |
|
|
Term
|
Definition
computer by which users access the server |
|
|
Term
|
Definition
GIS conventionaly developed using a hybrid approach that handled graphical and descriptive components of geospatial data separately |
|
|
Term
|
Definition
a proprietary of GIS software that handled graphical data |
|
|
Term
|
Definition
connection between the graphical data engine and the database management system (DBMS) |
|
|
Term
|
Definition
allow users to identify facts about the real world and transform these facts into geographic objects useful for geospatial data processing and analysis |
|
|
Term
The use of object oriented technologies |
|
Definition
has transformed GIS from automated filing cabinets of maps into smart machines for geographic knowledge |
|
|
Term
|
Definition
allows for users to customize their applications by using scripting language to build software extensions |
|
|
Term
|
Definition
software engineering methodolgy that has been evolving since the early 1990s, addresses the integration of separate computer based applications such as document imaging, optical character recognition, database query. |
|
|
Term
GIS as a field of academic study |
|
Definition
- Cartography
- remote sensing
- mathematics
- statistics
- computer science
- information technology
- geography
- urban planning
- resource management
|
|
|
Term
GIS as a branch of information technology |
|
Definition
- cartography
- remote sensing
- computer programming
- software-specific training
- workshops
- laboratories
|
|
|
Term
GIS as a data institution |
|
Definition
- information technology
- law
- sociology
- antrhopology
- cognitive science
- economics
- political science
- public administration
|
|
|
Term
|
Definition
Scales of interest to human activity/interaction. Refers to spaces concerning the Earth's surface or near-surface |
|
|
Term
|
Definition
Can refer to a theoretical or mathematical space and can thus be applied to all spaces and scales, real and otherwise |
|
|
Term
|
Definition
The commonality of both the data and the problems that the systems are developed solve is geography, i.e. location, distribution, pattern and relationship within a specific geographical reference framework |
|
|
Term
|
Definition
data usually recorded at relatively small scales and must thus be generalized and symbolized |
|
|
Term
|
Definition
GIS is a collection of hardware, software, data, policies, procedures, and people for the input, storage and retrieval, manipulation and analysis, output and modeling of spatially referenced data |
|
|
Term
|
Definition
emphasis on landownership and other castral applications. lands divided into parcels that have legal descriptions |
|
|
Term
|
Definition
natural resources IS, used for habitat/wildlife evaluation and management, flood hazard mitigation, conservation easement, etc. |
|
|
Term
|
Definition
- CAD, CAM, CAC
- automated mapping
- Database Management Systems (DBMS)
|
|
|
Term
Types of GIS Software Packages
|
|
Definition
- Grass
- ArcInfo
- ArcMap
- IDRISI
|
|
|
Term
Computing planar distance using distance theorem |
|
Definition
d-√(x2-x1)^2 + (y2-y1)^2
where X2-x1 = difference in longitude
where y2-y1 = difference in latitude
D = distance between two points |
|
|
Term
|
Definition
assumed that map itself was a final product designed to communicate a spatial pattern via symbols, class limit determinations etc. |
|
|
Term
|
Definition
maintains raaw data in computer storage device for subsequent analysis - GIS |
|
|
Term
|
Definition
generalized view of an area as seen from above typically reduced in size |
|
|
Term
|
Definition
subfield of geography that focuses on map-making |
|
|
Term
|
Definition
ratio of map units to ground units |
|
|
Term
|
Definition
process of transforming spherical Earth to flat map |
|
|
Term
|
Definition
can be perspective or nonperspective |
|
|
Term
Perspective Map projection |
|
Definition
strictly geometric, use of a point of origin, or viewpoint, and a surface of projection. viewpoint selected baased on a certain critieria |
|
|
Term
Nonperspective Map Projection |
|
Definition
modifying the perspective projection to maintain desired properties - Ex. Mercator Map |
|
|
Term
|
Definition
can be expressed according to generalized functional relationships between geographical coordinates of a point on the Earth's surface and the coordinates on the plane |
|
|
Term
|
Definition
parallels are always parallel to each other, meridian converge at poles and are evenly spaced along any parallel; distance between parallels decreases towards poles |
|
|
Term
Map projection properties |
|
Definition
- area
- shape
- distance
- direction
|
|
|
Term
|
Definition
- to maintain shape make the scale along the meridian and paralell the same in both directions
- preserving shaped distorts the distances
|
|
|
Term
|
Definition
intersect parallels at right angles |
|
|
Term
|
Definition
- shows spatial distributions and relative sizes of spatial features
- tradeoffs of preserving area are the shape distance and occasionally directions are distorted
|
|
|
Term
|
Definition
inherent property of azimuthal class projections since all meridians pass through the pole |
|
|
Term
|
Definition
naturally preserves shapes and true direction |
|
|
Term
|
Definition
- Gerardus Mercator
- Cylindrical projection
- true shape
- meridians equally spaced
- rhumb lines enable plotting direction (good for navigation)
|
|
|
Term
Disadvantages of Mercator Projection |
|
Definition
midlatitude and poleword landmasses dramatically stretched
|
|
|
Term
|
Definition
- Cylindrical
- conical
- planar
|
|
|
Term
|
Definition
- cylinder assumed to circumscribe a transparent globe such that a cylinder touches the equator throughout its circumference
- meridians are vertical and parallel lines
- parallels are horizontal straight lines
|
|
|
Term
|
Definition
- come placed over globe such that the apex of the cone is exactly over the polar axis
- cone must touch globe along a parallel of latitude
- along standard parallel, scale is correct
- parallels are arcs of circles
|
|
|
Term
Planar or Azimuthal Projections |
|
Definition
- Plane Touches the globe at North or South Pole
- Like a cone flattened until vertex reaches a limit of 180 degrees
- shape is circular
- meridians look like straight lines eminating from the circle
- parallels are complete circles centered at the pole
|
|
|
Term
Universal Transverse Mercator (UTM) |
|
Definition
- used to define horizontal positions world wide 6 degree zones each mapped by transverse Mercator Projection
|
|
|
Term
|
Definition
- preserves land masses
- very little distortion in both shape and area
- no more than 2% error
|
|
|
Term
Defining Projections in Arc/Info |
|
Definition
for coverages, tins and grids projection information is stored as a PRJ file within their subdirectory and store as a file name .prj |
|
|
Term
|
Definition
projection information is written to the PRJ of a coverage
|
|
|
Term
|
Definition
projection information is written to the PRJ of a grid |
|
|
Term
|
Definition
projection information is written to the PRJ of an ASCII text file |
|
|
Term
|
Definition
projection information is written to the PRJ of a tin |
|
|
Term
|
Definition
data set for which the projection information is being defined |
|
|
Term
|
Definition
the representation of the location of real world features within the spatial framework of a particular coordinate system |
|
|
Term
|
Definition
provide a rigid spatial framework by which the positions of real-world features are measured, computed, recorded, and analyzed |
|
|
Term
|
Definition
deal iwth representing the physical shape of the Earth via a mathematical surface |
|
|
Term
|
Definition
- the reference surface for horizontal positions
- physical shape of the real earth is closely approximated by the rotational ellipsoid
- reference surface for horizontal coordinates (lat/long)
|
|
|
Term
|
Definition
Amount of polar flattening
where a and be are lengths of major and minor semi axes of the ellipse |
|
|
Term
|
Definition
|
|
Term
|
Definition
- means earthlike
- shape of the earth if oceans were allowed to flow freely under the continents
- geoid rises over the continents and is depressed over the oceans
- coincides with mean seal level
- reference surface for vertical coordinates
|
|
|
Term
|
Definition
surface on which the gravity potential is constant everywhere |
|
|
Term
|
Definition
model that describes the position, direction, and scale of relationships of a reference surface to positions on the surface of Earth |
|
|
Term
|
Definition
- established to provide positional control that supports surveying and mapping projects covering large geographic areas
- provide positional control that supports surveying and mapping projects covering large geographic areas
|
|
|
Term
|
Definition
- zero surface from which all elevations or heights are measured
- MSL was used as a vertical datum since MSL is available worldwide
|
|
|
Term
|
Definition
- referenced by 3-D cartesian coordinate systems (x,y,z) with the origin coincident with the center of the ellipsoid
|
|
|
Term
Relation b/w Coordinate Systems and Map Projections |
|
Definition
- coordinate systems formed on the basis on map projections but they are not map projections themselves
- coordinate systems and map projections are different concepts with different purposes
- map projections define how poisitons on Earth's surface are transformed onto a flat map surface
- the coordinate system is then superimposed on the surface to provide a referencing framework by which positions are measured and computed
|
|
|
Term
Universal Transverse Mercator |
|
Definition
projection is used to define the horizontal positions into 6 degree zones, each mapped by the Transverse Mercator projection with a central meridian in the center of the zone |
|
|
Term
|
Definition
- Topological Relationships
- continguity- next to sharing a border
- connectivity - connected to, allowing flow from one to the other
- proximity- near
- closure contained
|
|
|
Term
|
Definition
always interested in location |
|
|
Term
|
Definition
easily handled by non-spatial databases
spatial attributes and relationships are not handled well by non-spatial databases |
|
|
Term
|
Definition
Land Surveying
Remote Sensing
Global Positioning System |
|
|
Term
Geographic Data Collection |
|
Definition
- ground surveys
- tape measures
- LIDAR
|
|
|
Term
Global Position Systems (GPS) |
|
Definition
- U.S. DoD project devised in 1970s
- constellation of 24 satellites
- 6 orbital planes
- 55 degree inclination
- receiver computes position, velocity, time, four GPS satellites used to calculate position in 3 dimensions to offset receiver clock errors
|
|
|
Term
Radio Frequency Identification (RFID) |
|
Definition
- Can be passive or active
- can range from few cms to 20-30 ft
- high powered tags can tansmit into low orbit
- Point of sale terminals used for customer tacking
|
|
|
Term
|
Definition
- Can be virtually undetectable
- can be woven into materials
- uses a 96-bit code as a string of 96 zeroes and ones
|
|
|
Term
|
Definition
- Digital Raster Graphic (DRG)
- Digital Line Graph (DLG)
- Digital Elevation Model (DEM)
- LiDAR derived elevation data
|
|
|
Term
Non spatial Data for Thematic Mapping |
|
Definition
- Geographic referencing for attribute data uses the hierarchical referencing system
- discrete often parcelled based
- municipal addresses
|
|
|
Term
Non Spatial Levels of Measurement |
|
Definition
usually determined by the valid operations
|
|
|
Term
Steven's Levels of Measurement |
|
Definition
- Binary Scale
- Nominal Scale
- Ordinal Scale
- Interval Scale
- Ratio Scale
|
|
|
Term
|
Definition
presence or absence. frequently used to represent discrete data in raster systems |
|
|
Term
|
Definition
making distinctions in kind/class category |
|
|
Term
|
Definition
- Difference in Rank
- can go beyond just equal or not equal
- sorting is possible
- non parametric/ qualitative
|
|
|
Term
|
Definition
uses a relative scale, zero is arbitrary and can have negative values |
|
|
Term
|
Definition
uses an abosolute zero. zero represents the absence of phenomena |
|
|
Term
Criticism of Steven's levels of measurement |
|
Definition
- not adequate to address all possible circumstances in cartography and GIS
- ratio is not the highest level of measurement
- cyclic measures do not fit the concept of scale well
|
|
|
Term
|
Definition
defines our terms, levels of measurement, translates computer representation or attributes. |
|
|
Term
|
Definition
- Manual coordinate capture
- attribute capture
- digital coordinate capture
- data import
|
|
|
Term
|
Definition
- manual point, line, and area feature of editing
- manual attribute editing
- automated error detection and editing
|
|
|
Term
|
Definition
- copy, subset, merge data
- versioning
- data registration and projectiong
- summarization, data reduction
- documentation
|
|
|
Term
|
Definition
- spatial query
- attribute query
- interpolation
- connectivity
- proximity and adjacency
- buffering
- terrain analysis
- boundary dissolve
- spatial data overlay
- moving window analysis
- map algebra
|
|
|
Term
|
Definition
- map design and layout
- hardcopy map printing
- digital graphic production
- export format generation
- metadata output
- digital map serving
|
|
|
Term
|
Definition
- historically cartographic products from GIS not Good
- Digital Maps (soft copy)
|
|
|
Term
human computer interaction |
|
Definition
optimization of communication and presentation of geographic information |
|
|
Term
|
Definition
user views intermediate results of spatial analysis and based on those results, the algorithmic parameters may be interactively changed |
|
|
Term
|
Definition
- mapping a real or conceptual 3-D geographical volume with quantitative line symbols. It is a planimetric representation of a 3-D volume
|
|
|
Term
Two forms of Isarithmic Maps |
|
Definition
Both involve the planimetric mapping of the traces of the intersections of horizontal planes with the 3-D surface |
|
|
Term
|
Definition
generated from point data
Actual - measure with instruments or other point sampling techniques
Derived- statistiacal measures and magnitudes |
|
|
Term
|
Definition
generated from mapping data that occured over geographic areas called unit series |
|
|
Term
Isarithmic Map Construction |
|
Definition
- magnitude or value of this isarithmic lines represent their vertical distance from teh data
- planes constructed parallel to the Datum - each isarithm will have a constance magnitude, distance from the datum
|
|
|
Term
When to use Isarithmic Maps |
|
Definition
- mapped data must be a geographical volume and must have a surface that bounds the volume
- data must be continuous, not discrete
- must be familiar with the phenomenon being mapped
|
|
|
Term
Nearest Neighbor Interpoloation (Thiessen Polygons) |
|
Definition
- Assumption is that the value at each given location is the same as teh value of the nearest observation
- Uses the concept of Thiessen Polygons
- defined around each observation
- only one observation is contained in each polygon
|
|
|
Term
Advantages of Nearest Neighbour Interpolation |
|
Definition
most appropriate for qualitative data (nominal in scale) |
|
|
Term
|
Definition
- assumes values only change at the borders
- does not perform well with interval or ratio scale data because it is a continuous surface
- resulting surface is discontinuous without smooth graduations between observed values
|
|
|
Term
Inverse Distance Weighted Interpolation |
|
Definition
- Assumption:
- the value of an attribute z for each unvisited grid cell location is DISTANCE WEIGHTED AVERAGE of data points located at nearby observations
- Original data points are located on a regular grid or irregularly distributed and interpolated to locations on a denser regular grid
|
|
|
Term
Inverse Distance Weighted Method |
|
Definition
d= distance between given and observed
z- observation point
N = number of observations
i = iteration
z1 = weighted value at a given point
T - weighting parameter |
|
|
Term
What is the Relationship between r and nearby points in the Inverse Distance Weighted Method |
|
Definition
An increase in r means that the distance is more heavily weighted; thus, the predicted value will be more like closer values |
|
|
Term
Inverse Distance Weighted IDW Interpolation summary
|
|
Definition
- based on the principle in geography that things closer together are more similar
- if considering a location with no measured valuek IDW will look within a specified neighborhood around the point of interest and identity of the measured value
- the closer observations will influence the predicted value more than observations measured farther away
- closer points are thus more heavily weighted than points further away.. IDW as the distance from the point-to be predicted increase the values become more inversely wieghted
|
|
|
Term
Inverse Distance Weighted Interpolation |
|
Definition
Advantages
- results in a smooth and continuous surface that changes between observations
- derived surface passes through observed values
Disadvantages
- requires subjective selection of parameters
- does not interpolate beyond min and max values in observation sets
|
|
|
Term
|
Definition
- Graphic design produces visual forms
- assign qualitative and quantitative meaning s to the distinctive marks - relate graphic characteristics of the marks to attributes of the data
- arrange the marks in a total composition that enhances map communication with teh user, wehre the intended information is conveyed
- skill and artistry important for map design
|
|
|
Term
Criteria for a Good Decision |
|
Definition
- should be suited to the needs of map users
- should be easy to use
- should be accurate, present information without error and distortion
- should be clear, legible, and aesthetically pleasing
- symbols, color, layout, and typographic appearence
- should be thought provoking and communicative
|
|
|
Term
|
Definition
- point, line and area polygon symbols are the basic elements used to create all visual design
|
|
|
Term
|
Definition
|
|
Term
|
Definition
exhibit directions as well as position |
|
|
Term
|
Definition
exhibits exten, direction, and position - graphically uniform over the area; even color uniform repetition of a point or line symbols |
|
|
Term
|
Definition
regular or geometric shapes, irregular shapes as well |
|
|
Term
|
Definition
different geometric dimensions |
|
|
Term
|
Definition
hue, value, and saturation |
|
|
Term
|
Definition
combination of basic reptitive graphic elements produces an aerial graphic effect |
|
|
Term
|
Definition
Exhibits the characteristics of arrangemetn texture/spaceing and orientation |
|
|
Term
|
Definition
shape and configuration of component marks that make up a patter |
|
|
Term
|
Definition
size and spacing of component marks that make up a pattern, fine texture; closely spaced small marks |
|
|
Term
|
Definition
- Clarity and Legibility
- Contents, Information, and Map Space
- Visual Contrast
- Figure-Ground Organization
- Visual Hierarchy
|
|
|
Term
Map Composition and Layout |
|
Definition
- Map Elements
title
Map Legend
Map scale
Map symbols
Credits
- Aesthetic of Map Compositon
- Visual Balance
|
|
|
Term
|
Definition
- it is widely accepted that a rectangle with sides having a proportion of about 3-5 seems to be the most aesthetically pleasing formats
- in mathematics, a geometric proportion in which a line is divided such that the ratio of the length of the longer line segments to the length of the entire line is equal to the length of the shorter line segment to the length of the longer line segment
|
|
|
Term
|
Definition
- used to name places; identify or label objects, provides titles, legends, and other explanatory elements
- letterform characteristics, size, letter spacing typeface personalities and legibility are important aspects of lettering.
|
|
|
Term
|
Definition
established technique in GIS. Draping a topographic or thematic map onto a 3-D terrain surface is effective but relies on abstract colors, shading, and symbols. Draping a satellite image such as a digital orthophoto, results in good surface texture and can produce visualizations suitable for depicting landscape-scale vegetation patterns |
|
|
Term
|
Definition
combines video imaging techniques with geometric registration typically undertaken within a GIS. its rarely used on a production bases due to the difficulty in accurately geo-referencing the photographic video image with the 3-D perspective |
|
|
Term
VRML (Virtual Reality Modeling Language) |
|
Definition
standard file format for representing 3-D interactive vector graphics designed particularly for use with the world wide web |
|
|
Term
|
Definition
the number of transistors incorporated in a chip will approximately double every 24 months. |
|
|
Term
Digital Representation of Geographic Data |
|
Definition
- Geographic Databases are dynamic, not static; allows interactive data analysis
- data models; methods of data representation
|
|
|
Term
|
Definition
representation of reality, not the thing itself, it is a model |
|
|
Term
|
Definition
an entity being represented by an object. A defined entity and its oobject representation. this term does not make a distinction between the real thing or the model |
|
|
Term
|
Definition
A real world phenomneon; entities have relationships and attributes which can be spatial or non spatial |
|
|
Term
|
Definition
|
|
Term
|
Definition
distributed continuously over a large area |
|
|
Term
Representing Geographic Space |
|
Definition
approaches to representation of real world in geographic databases;
- Object based model
- field based model
|
|
|
Term
|
Definition
- contiguity - next to sharing a border
- connectivity- connected to
- proximity
- closure/ containment
|
|
|
Term
|
Definition
always interested in location |
|
|
Term
|
Definition
component of Berry's geographic matrix |
|
|
Term
|
Definition
time, algebra, measurement, relationship |
|
|
Term
|
Definition
- Time measurement for objects can be made at an instance which is a measurement of existence
- can also be made for a duration which is a measurement of evolution, occurence, and permanence
|
|
|
Term
Relationship between Time and Space |
|
Definition
- spatial changes refer to geometric transformation of an object and includes the change in location, size, orientation and form
- spatial relationships among objects may change as a function of geometric transformations
|
|
|
Term
Temporarl Attributes of Geographic Process |
|
Definition
- Generation Time: time at which object is created
- Duration Time: time during which an object is in existence or is observed
- Temporal Significance: important of given event
- Temporal Scale: analogous to map scale adapted to time
|
|
|
Term
|
Definition
how data are classified and feature coded to facilitate identification of relationships between data items |
|
|
Term
|
Definition
method by which data items are stored on a computer |
|
|
Term
Data Classification/classification scheme |
|
Definition
purpose of classification scheme: provide an a priori standard with which individual observations can be observed and recorded during data collection process |
|
|
Term
Two components of Classification Schemes |
|
Definition
- Descriptive Names of classes and subclasses
- Definitions of classes and subclasses
|
|
|
Term
|
Definition
spatial object that has specific properties that categorically seperate it from other entities. These properties are known as attributes |
|
|
Term
Entity class, entity type, or feature class |
|
Definition
collectively, entities that share common attributes |
|
|
Term
|
Definition
process of encoding the values of the entities and attributes to graphical elements during the data collection process |
|
|
Term
Feature Codes comprised of two components |
|
Definition
|
|
Term
|
Definition
identifies the entity type to which a particular entity belongs |
|
|
Term
|
Definition
Identifies the attributes that an entity has, also referred to as a attribute code |
|
|
Term
|
Definition
alphabetic, numeric, or alphanumeric |
|
|
Term
|
Definition
function of the number of bits used |
|
|
Term
|
Definition
smallest addressable unit in the computer, an 8-bit data item |
|
|
Term
|
Definition
basic building block of data organization in the computer, an occurence or instance of a certain characteristic pertaining to an entity |
|
|
Term
|
Definition
data items are occurrences of different characteristics pertaining to the same entity |
|
|
Term
|
Definition
a stored record, or tuple |
|
|
Term
|
Definition
formed by grouping a record together |
|
|
Term
True/False
Computer processing is based on databases rather than data files
|
|
Definition
|
|
Term
Raster Data Representation |
|
Definition
Grid Cells representing areas of the same entity type have identical values or patterns of the values tend to be spatially clumped |
|
|
Term
|
Definition
run length encoding raster data compression algorithm |
|
|
Term
Raster Data Representation Encoding |
|
Definition
Adjacent cells along a row wit hthe same values are treated as a group. Value is stored once together with the number of cells that comprise the run |
|
|
Term
|
Definition
goal is to reduce seek and latency time in answering common large queries. For spatial databases this implies that objects are adjacent in space and are commonly requested jointly by queires should be stored physically together in secondary memory |
|
|
Term
Three types of Clustering for SDBMS |
|
Definition
- Internal Clustering
- Local clustering; and
- Global Clustering
|
|
|
Term
|
Definition
to speed access to a single object, the complete representation of one object is stored in one disk page, assuming the size is smaller than the free space on the page. otherwise the object is stored on multiple, physically consecutive pages |
|
|
Term
|
Definition
to speed access to several objects, a set of spatial objects is grouped onto one page |
|
|
Term
|
Definition
a set of spatially adjacent object is stored not on one but several physically consecutive pages that can be accessed by a single read request |
|
|
Term
|
Definition
Design of spatial clustering techniques is more difficult than traditional clustering since there is no natural order in multi-dimensional space where spatial data resides. Also disk storage is logical and is only 1-D device |
|
|
Term
|
Definition
regarding addressing systems, procedures exist to represent relative locations of the 2 or 3-D kind of 1-D sysstems |
|
|
Term
|
Definition
- Distance preserving manner needs to be mapped from higher dimensional space
- No two points in the space are mapped onto the same point on the line, and should be one to one
|
|
|
Term
|
Definition
total longer path than row prime sequence, every other line is traversed in a reverse direction and have several placves in which neighbors on the path are not adjacent in space |
|
|
Term
Diagonal and spiral orders |
|
Definition
like the row prime sequence in possessing the property of immediate adjacency |
|
|
Term
|
Definition
mixes up corner and side joins |
|
|
Term
|
Definition
Terminates in the middle, making it impossible to connect other blocks of space |
|
|
Term
|
Definition
- Total length of the path
- variability in unit lengths, where unit length is the distance from one point on the path to the next sequence;
- the average distance on the path from the tiles to their neighbors in space
|
|
|
Term
|
Definition
- Special fractal curves which have characteristics of completely covering an area or volume
- topological dimension of 2
- if point is 0-D, not possible to define a 1-D curve passing thru the infiinity point
- if point is conceptualized as 2-D square the side of which tends toward zero, it is possible to find a curve filling a 2-D space
- In 3-D a point can then be defined as a small cube for which the side length tends toward zero and the curve as a 3 D curver
|
|
|
Term
Paths as Space Filling Curves |
|
Definition
- curve must pass only once to every point in multidimensional space
- two points that are neighbors in space must be neighbors on the curve
- two points that are neighbors on the curve must be neighbors in space
- it should be easy to retrieve neighbors at any point
- curver corresponds to a mapping from a multi- to a 1-D space
- curve should be able to be used for variable spatial resolution
- curve should be stable
|
|
|
Term
|
Definition
facilitates retrieving neighbors; while neighboring points in space are not always neighbors on the curver, they usually are |
|
|
Term
|
Definition
passes through all points in a set by means of single length steps only. it meets many of the criteria of an ideal curve, but does not enable the easy retrieval of neighbors. Unstable |
|
|
Term
Algorithm for the Z curve (peano) |
|
Definition
- Read the binary representation of the x and y coordinates
- Interleave the bits of the binary numbers into one string
- Calculate the decimal value of the resulting binary string
|
|
|
Term
Algorithm for the Hilbert Curve |
|
Definition
- Read in the n-bit binary representation of the x and y coordinates
- interleave bits of the two binary numbers into one string
- divide the string from left to right onto 2-bit strings
- give decimal valu, d for each 2 bit string
- for each number j in the array i
- convert each number in the array to its binary representation, concatenate all the strings in order from left to right, and calculate teh decimal value
|
|
|
Term
|
Definition
Hilbert curvbe method is slightly better than the Z-curve because it does not have any diagonal lines |
|
|
Term
|
Definition
square region that is the result of one or more quadtree subdivisions of the original image. a quadtree recursively subdivides space into four equal parts |
|
|
Term
|
Definition
Each object can be uniquely representaed by the Z-values of its blocks, Each such z-Value can be treated as a primary key of a record of the form |
|
|
Term
Space Filling curves for GIS systems |
|
Definition
- Make scanning operations more efficient (hardware devices or scanning thru datafiles)
- They are used as spatial indexes, simplifying 2-D addressing as 1-D addressing
|
|
|
Term
Vector Data Representation |
|
Definition
- Vector Data model is object based
- best utilized to represent discrete objects
- spatial objects are represented individually and represented mathematically, via coordinates
- Vector data model is more complex than raster data model
- Wide variety of formats
|
|
|
Term
Vector Data Representation Formats |
|
Definition
- Decomposing spatial objects into basic graphical elements
- use of topology (spatial relationships) as well as geometry coordinates
|
|
|
Term
|
Definition
- Lines (arcs)- begin and end with a node
- Polygons (areas) - closed loop of coordinates
- points
|
|
|
Term
|
Definition
- not structured vector data from map digitizers, CAD- stores graphical elements, not graphical entities
- redundant- stored twice
- must be structured for use in GIs
|
|
|
Term
|
Definition
- Structured vector data
- many variants of model - most common is the arc-node data model
- Arc = line segments
- node = end points of line segments
- stores graphical elements rather than graphical entities
- stored topological relation allows graphic entities to be constructed
|
|
|
Term
Spatial Data Transfer Standard (SDTS) |
|
Definition
robust way of transferring earth referenced spatial data between dissimilar computer systems with the potential for no information loss. it is a transfer standard that embraces the philosophy of self-contained transfers, spatial data, attribute, goereferencing, data quality report, data dictionary
|
|
|
Term
Classification and intended use of objects in STPS |
|
Definition
- Geometry only - for drawing, display and geometrically defined operations on raster and vector data structures
- geometry and topology - for vector data structures that use geometric drawing and topological operations
- topology only - for certain analytical operations
|
|
|
Term
|
Definition
- a zero dimensional object that specifies geometric locations
- Entity point - point used for identifying the location of point features such as tower, buoys
- Label Point - a reference point used for displaying map and chart text to assist in feature identification
- Area Point- representative point within an area usually carrying attribute information about that area
|
|
|
Term
|
Definition
zero dimensional object that is a topological junction of two or more links or chains, or an end point of a link or chain |
|
|
Term
|
Definition
- A line is a generic term for a one dimensional object
- Line segment- direct line between two points
|
|
|
Term
|
Definition
connected nonbranching sequence of line segments specified as the ordered sequence of points between those line segments. A string may intersect itself or other strings |
|
|
Term
|
Definition
a locus of points that froms a curve that is defined by a mathematical expression |
|
|
Term
|
Definition
a topological connection between two nodes. A link may be directed by ordering its nodes |
|
|
Term
|
Definition
- a directed nonbranching sequence of nonintersecting line segments and arcs bounded by nodes, not neccesarily distinct at each end
|
|
|
Term
|
Definition
chain that explicity references left and right polygons and start at the end of nodes it is a two dimensional manifold |
|
|
Term
|
Definition
chain that explicitly references start and end nodes and not left and right polygons |
|
|
Term
|
Definition
sequence of nonintersecting chains or strings and or arcs with closure. a ring represents a closed boundary, but not the interior area inside the close boundary |
|
|
Term
|
Definition
Area not including its boundary |
|
|
Term
|
Definition
area consisting of an interior area, one outer G ring and zero or more non intersecting nonnested inner G-rings. No ring, inner or outer, must be collinear with or intersect any other ring of the same G-polygon |
|
|
Term
|
Definition
area that is two dimensional component and only one two dimensional maniforld |
|
|
Term
|
Definition
defines the part of the universe that is outside the perimeter of the area covered by other GT-polygons. This polygon completes the adjacency relationships of the perimeter links |
|
|
Term
|
Definition
two dimensional picture element that is the smallest nondivisible element of a digital image |
|
|
Term
|
Definition
two dimensional object that represents the smallest nondivisible element of a grid |
|
|
Term
Two dimensional aggregate spatial objects |
|
Definition
Certain two dimensional aggregate spatial objects must be defined to provide context for many of the simple objects defined above. these aggregate objects are necessary for the definition of raster objects, topology |
|
|
Term
|
Definition
Two dimensional array of regularly spaced picture elements (pixels) constituting a picture |
|
|
Term
|
Definition
two dimensional set of grid cells forming a regular tesselation of a surface |
|
|
Term
|
Definition
Each row and column of the Grid may have independent thickness or width |
|
|
Term
|
Definition
an areally distributed set of spatial data representing entity instances within one theme, or having one common attribute or attribute value in an association of spatial objects. A layer is specifically a two, three, or N-dimensional array of attribute values associated with all or part of a grid, image, voxel space or any other type of raster data. |
|
|
Term
|
Definition
one or more related overlapping layers for the same grid, digital image, voxel space, or any other type of raster data. the corresponding cells between layers are registered to the same raster object scan reference system . The layers overlap but need not be of the same spatial extent |
|
|
Term
|
Definition
set of topologically interrelated zero-dimensional, one dimenional and sometimes two dimensional objects taht conform to a set of defined constraint rules |
|
|
Term
|
Definition
node and link or chain objects of the graph occur or can be represented as though they occur upon a planar surface. Not more than one node may exist at any given point on the surface |
|
|
Term
|
Definition
a graph without two dimensional objects. If projected onto a two-dimensional surface, a network can have either more than one noede at a point, and intersecting links or chains without corresponding nodes |
|
|
Term
|
Definition
a three dimensional object that represents the smallest nondivisible unit of a voxel of space (volume) (think cube) |
|
|
Term
|
Definition
3 D array of voxels in which the volumetric dataset resides. The volume represents some measurable properties or independent variables of a real object or phenomenon. |
|
|
Term
|
Definition
- documents knowledge of data accuracy, provenance, and age necessary for good decision making
- can build a GIS catalog, internal or external portals allow others to search, find, and access the GIS resources
|
|
|
Term
|
Definition
Federal Geographic Data Committe with the goal to provide a complete description of a data source |
|
|
Term
|
Definition
- International Organization for Standardization
- attempts to satisfy the requirements of all existing metadata standards; flexible genearl or detailed descriptions
|
|
|
Term
|
Definition
- eXtensible Markup Language was developed by the World Wide Web Consortium
- standard for designing text formats
|
|
|
Term
|
Definition
A GIS is a collection of hardware, software, data, policies, procedures, and people for the input, sotrage, & retrieval, manipulation and analysis, output and modeling of spatially referenced data |
|
|
Term
|
Definition
- object oriented database systems
- Small World
|
|
|
Term
|
Definition
Sometimes referred to as a scaleless system but it is not true because you are not changing the original scale that the data was originally collective |
|
|
Term
|
Definition
deals with non-euclidean coordinates |
|
|
Term
|
Definition
can amplify or cancel out your operations. Understanding how errors propagate is extremely important |
|
|
Term
Digital Raster Graph (DRG) |
|
Definition
scanned hardcopy map that has been georeferenced |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
Differential Post Processing |
|
Definition
Most accurate form of GPs |
|
|
Term
|
Definition
- Plane (flat surfaces) - azimuthal projection family
- cylinder - cylindrical projection family
- Cone - Conic projection family
|
|
|
Term
|
Definition
- Gnomonic- Light source is at the center of the globe (flashlight shing at the center)
- Stereographic: light source is at the point exactly opposite of the point of tangency of the projection surface (from the poles)
- Orthographic- at a considerable distance (infinite point): Light rays are parallel, often used for persepctive views which means the map is often perspective but not conformal or equal in area.
|
|
|
Term
Normal (regular Projection) |
|
Definition
- normal orientation for a plane is tangent at the pole (polar azimuthal)
- cylindrical is normally oriented so that it is tangent along equator (equitorial)
- A cone is normally oriented so that it is tangent along a parallel with its apex over the pole, in alignment with the axis of rotation
|
|
|
Term
|
Definition
- projection is tuned 90 degrees from normal
- for a plane, the plane is tangent at the equator
- for a transverse cylindrical projection, the cylinder is tangent along a meridean
- transverse conic: not frequently seen
|
|
|
Term
|
Definition
Projection surface lies at an angle somewhere between the normal and transverse position |
|
|
Term
|
Definition
- The projection surface is tangent to the globe
- a planar surface is tangent to the globe only at one point
- tangent cones and cylinders contact, the globe along a line
|
|
|
Term
|
Definition
- projection surface intersects the globe instead of merely touching the surface
- a planar surface intersects the globe forming a small circle along the intersection line
- A cone or cylinder intersects the globe resulting in two small circles along intersecting lines
|
|
|
Term
|
Definition
- point at which a planar surface touches the globe
- only the one standard point exists for a planar tangent projection
- directions from the point are accurate greate circles passing through are represented as straight lines
- Distortions of area angle have a circular pattern and increases with distance from standard point
|
|
|
Term
Standard line (line of true scale) |
|
Definition
- line along which projection surface touches or intersects the globe
- this is the one standard line when a polar surface intersects the globe or a cone or cylinder is tangent to the globe
- there are two standard lines when cone or cylinders intersect the globe
- along a standard line a map has no distortions and map scales is identical to the nominal globe
- Geometric distortion generally increases with distance
|
|
|
Term
|
Definition
demographic information about a population that is spatially consolidated |
|
|
Term
|
Definition
- honor the data points upon which interpolation is based
- surface passes through all points whose value is known
- proximal interpolation, R splines and Krigin methods all honor given data points
- Kriging may incorporate a nugget effect if so not exact interpolator
|
|
|
Term
Approximate Interpolators |
|
Definition
- used when uncertainty exists about given surface values
- utilize belief that in many data sets there are global trneds which vary slowly, overlain by local fluctuations which very rapidly produce uncertainty (error)
- Effect of smoothing will therefor reduce effects of error on resulting surface
|
|
|
Term
Stoichastic Interpolators |
|
Definition
- incorporate concept of randomness
- interpolated surface is conceptualized as one of many that might be observed all of which could have been produced with known data points
- Kriging is stoichastics because it allows statistical significane of the surface and uncertainty of predicted values to be computed
|
|
|
Term
Deterministic Interpolators |
|
Definition
- do not use probability theory
- example: TIN linear
|
|
|
Term
|
Definition
fuze up, precision up, knowledge up, and is easier to work with |
|
|
Term
|
Definition
Things closer together in space tend to be more similar than things further apart |
|
|
Term
Kriging Interpolation Method |
|
Definition
- geostatistical
- basis of the method is the rate at which the variance between point changes over space, this is expressed in the variogram which shows how the average difference between values at points changes with distance between points
- requires characterization of spatial data to set parameters
- usually more accurate
|
|
|
Term
|
Definition
RGB
- most applicable to computer display devices
- additive based on a mixture of Red, green, blue
- CAD system viewed as a cube with red green and blue dyes
Red + Green = Yellow
Red + Blue = Magenta
Green + Blue = Cyan
Red + Green + Blue = white
None = black |
|
|
Term
|
Definition
- tecktronic developed by HSV system to specify selection of color projection from tints to shades
- double cone with the central axis forming a lightness progression identical to black and white diagonal line through RGB cube
- Many color graphic programs specify color based on hue, lightness value, and saturation
|
|
|
Term
|
Definition
- Hue is given as an angle counter clockwise between 0 and 360
- lightness value is given as an integer between 0 (black) and 100 (white) and saturation between 0 (gray) and 100 (pure color)
- triangular slice for each hue can also be viewed as a plane cut from the RGB cube and deforemed into the HSV triangles
- The transformation is linear- simple equations can be used to transforms HSV specifications into RGB and vice versa
|
|
|
Term
|
Definition
- colors in the HSV are defined with respect ot normalized red, green, and blue values
- R= R/ R+G+B
- G= G/R+G+B
- B= B/R+G+B
- R+G+B= 1
|
|
|
Term
|
Definition
|
|
Term
|
Definition
H= cos-1{1/2 (r-g)+(r-b)/ [(r-g)2+(r-b)(g-b)]1/2} |
|
|
Term
|
Definition
S = 1-3/ R+G+B [min(r,g,b)] |
|
|
Term
Range of calculated saturation and intensity |
|
Definition
S and V [0,1] but can be rescaled down to [0,100] |
|
|
Term
|
Definition
- normalize the Saturation and Intensity to the range of [0,1] and H to the range of [0,360]
- R = 1/3 (1-S)
- G= 1/3 (1+Scos(H)/Cos60-H
- B = 2 - (r+g)
- range of computed r,g,b is [0,1] but can be rescaled [0,255]
|
|
|
Term
|
Definition
contians coordinate information |
|
|
Term
|
Definition
same occurence in a certain feature |
|
|
Term
Spatial Data in Raster Structure |
|
Definition
- almost no coordinates are stores, in fact, there only one coordinate pair that is stored - the origin
- Block orientation
- Storage
coordinate pair, cell size, orientation, orientation angle, matrix size # of rows, columns, projection info, scale |
|
|
Term
|
Definition
- Geometry and topology are limited but implicit in data structure
- there is no connectivity
- have contiguity built into arrangement of cells just need to know the numbering scheme and can do proximity analysis
- Index schemes - order which we are storing data into the system, z scan back and forth
- Problem: takes time to access the data we want, positions are close in space in sotrage
- type of index scheme is application dependent
|
|
|
Term
|
Definition
- Basic Unit - Chain
- 3 Topological Objects
- Nodes - 0 dimensional connection between chains
- Chains - 1 D connection between nodes
- Polygons - 2-D polygons share chain boundaries
|
|
|
Term
|
Definition
- nodes bound chains
- chains cobound nodes
- polygons co bound chains
- chain is basic unit since it relates to both nodes and polygons
|
|
|
Term
|
Definition
- From Node (left poly)
- To Node (Right poly)
- Chain is given a sense of direction
|
|
|
Term
|
Definition
Id, Point ID, List of Chains |
|
|
Term
|
Definition
ID, from node to node
topological information, deep structure
Line ID, or point poly - graphical shape info element - surface sturcture |
|
|
Term
|
Definition
ID, Label Point ID, Chain List |
|
|
Term
SQL Structured Query Language |
|
Definition
syntax for defining and manipulating from a relational database management system |
|
|
Term
|
Definition
- does not support SQL
- Fields- smallest named unit - represents a characteristic
Entity - Record, File, Database |
|
|
Term
|
Definition
collection of individual fields, an entry in the database |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
stores numbers and letters |
|
|
Term
|
Definition
- data fields
- money fields - allowing for only two decimal places
- integers- does not have decimal or fractional part
- reads- does have decimal or fractional part
|
|
|
Term
|
Definition
- Primary Index into the Database
- First Field that data are stored on
|
|
|
Term
|
Definition
- flat field
- hierarchical
- Network
- relational
- object oriented
|
|
|
Term
|
Definition
- a table or spreadsheet
- one file to hold all the data
- row records - number of objects
- columns - fields
- for 1 kind of object number of attributes = number of columns
- 2 kinds of objects MxN = land parcels and soil polygons
|
|
|
Term
Disadvantages of Flat Files
|
|
Definition
|
|
Term
|
Definition
- Looks like a flat file
- tables or files called relations
- records are called tuples
- fields are referred to as domains
|
|
|
Term
Organize data into multiple relations |
|
Definition
- minimizes the redundancy
- link seperate relations together by redundancy
- eliminates dead space
- process of creating a unique table/relations from redundant tables/relations called normalization
|
|
|
Term
|
Definition
- A way to add data to a table without having to change the program used to access it
- to create a system that allows multiple user access while maintaining security
|
|
|
Term
|
Definition
system for providing efficient, convenient, and safe multi-user storage of and access to massive amounts of persistent data |
|
|
Term
|
Definition
Data that outlives the software programs that were used to generate them |
|
|
Term
|
Definition
- Includes data, software/programs for storing and accessing the data as well as the security measures
- User- Query - Query Processor - transaction manager- storage manager- data metadata
|
|
|
Term
|
Definition
Enables Entry for new data or allow changes to the Database |
|
|
Term
|
Definition
describes the conceptual structuring of the data stored in the database |
|
|
Term
|
Definition
- 1970s starter were most hierarchical
- 1980s relational DB model developed, algebra that describes the model and a calculus for data retrieval
- 1990s - Object oriented DBs invented
- 1997 Relational database > hierarchical - took 17 years to surpass hierarchical usage
- 2000 - relational 60% data in the market
object 5-7%, hierarchical rest of market |
|
|
Term
2 main types of languages |
|
Definition
- Data Manipulating Language
- Data Definition Language
|
|
|
Term
Data Manipulating Language |
|
Definition
Commands such as SELECT, INSERT, DELETE |
|
|
Term
|
Definition
Commands for creating the schema stored as metadata |
|
|
Term
Levels at which DBs can be described |
|
Definition
- Logical Level
- Conceptual Level
- Research Area
|
|
|
Term
|
Definition
level at which users view the DB |
|
|
Term
|
Definition
concerned with infor design |
|
|
Term
|
Definition
Middleware
- connects individual DBs to other application programs; reconciles the different terms used among the various DBs
- Allows users to see at the logical level, one DB can perform just one query
|
|
|
Term
Disk Drivers are Rated by
|
|
Definition
- Seek Times
- Read Times
- DBs are concerned with where data are stored on the disk drive and affects retrieval time - good DBs have their own drivers to efficiently store data
|
|
|
Term
|
Definition
- Arc Spatial Database Engine
- Relational Model
- Examples
|
|
|
Term
|
Definition
|
|
Term
|
Definition
- like a class = set of similar entities/objects
- represented by a rectangle
|
|
|
Term
|
Definition
- properties of entities in an entity set
- Represented by an Oval
- So entity sets turn into tables and attributes turn into columns in the table
|
|
|
Term
|
Definition
- connect two or more entity sets
- Represented by diamonds
- taking represents a relationship set
- think of this as a table iwth one column for each connected entity set, and one row for each list of entities are connected
|
|
|
Term
Multiway (n-ary) relationships |
|
Definition
- Consider a relationship between students, courses, and TAs
- if we want to know which TAs are assisting with which students this design will not tell you that
|
|
|
Term
Multiplicity of Relationships |
|
Definition
- Many to Many
- Many to One
- One to One
|
|
|
Term
|
Definition
All of these relationships are many to many (use a round arrow to denote that drinkers have exactly one"
- many drinkers might like the same beer (many to One)
|
|
|