PROCESS IN DATA SYSTEMS PLANNING DATA INPUT DATA STORAGE DATA ANALYSIS DATA OUTPUT ACTIVITIES USER...
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Transcript of PROCESS IN DATA SYSTEMS PLANNING DATA INPUT DATA STORAGE DATA ANALYSIS DATA OUTPUT ACTIVITIES USER...
PROCESS IN DATA SYSTEMSPROCESS IN DATA SYSTEMS
PLANNING
ACTIVITIES
USERNEEDS
DATAINPUT
DATA STORAGE
DATA ANALYSIS
DATA OUTPUT
DATA STRUCTURESDATA STRUCTURES
Non spatialNon spatial FinanceFinance LibraryLibrary CommunicationCommunication TransportationTransportation
SpatialSpatial earthearth coordinatescoordinates
DATA STRUCTURESDATA STRUCTURES
NON SPATIALNON SPATIAL Management Management
Information Information SystemSystem
Decision Support Decision Support SystemSystem
Office Otomation Office Otomation SystemSystem
Artificial Inteligent Artificial Inteligent SystemSystem
SPATIALSPATIAL Environmental Info Environmental Info
SystemsSystems Infrastructural Info Infrastructural Info
SystemsSystems Cadastral Info Cadastral Info
SystemsSystems Social-economic Social-economic
Info SystemsInfo Systems
GIS DATA STRUCTURESGIS DATA STRUCTURES
traditional computer file structures that traditional computer file structures that allow for the storing, ordering and allow for the storing, ordering and searching of pieces of datasearching of pieces of data
higher level of organisation in the higher level of organisation in the computer called data base structures computer called data base structures allow more complex methods of managing allow more complex methods of managing datadata
GIS: GIS: graphic data structuregraphic data structure,, multiple multiple graphic data layers and their databasesgraphic data layers and their databases
SPATIAL SPATIAL DATADATA
POINTSPOINTS LINESLINES AREASAREAS can be represented by their respective can be represented by their respective
symbolssymbols SURFACESSURFACES most often represented either by point most often represented either by point
elevationselevations or other computer structuresor other computer structures, ,
POINT FEATURESPOINT FEATURES
Trees, houses, road intersections, and Trees, houses, road intersections, and many more.many more.
Each feature is said to be discrete in that Each feature is said to be discrete in that it can occupy only a given point in space it can occupy only a given point in space at any time.at any time.
These objects are assumed to have no These objects are assumed to have no spatial dimension. Each can be referenced spatial dimension. Each can be referenced by its locational coordinatesby its locational coordinates
LINEAR (LINE) FEATURESLINEAR (LINE) FEATURES
They are conThey are concceptualized as occupying eptualized as occupying only a single dimension in our coordinate only a single dimension in our coordinate space.space.
Roads, rivers, regional boundaries, fences, Roads, rivers, regional boundaries, fences, hedgerows, or any kind of object that is hedgerows, or any kind of object that is fundamentally long and very skinny.fundamentally long and very skinny.
Other lines such as political boundaries, Other lines such as political boundaries, have no width dimension to be concerned have no width dimension to be concerned about. In fact they are not physical about. In fact they are not physical entities at all, but rather, a construct of entities at all, but rather, a construct of political convention and agreement.political convention and agreement.
LINEAR (LINE) FEATURESLINEAR (LINE) FEATURES
They allow us to measure their spatial They allow us to measure their spatial extent by simply finding out how long they extent by simply finding out how long they are.are.
Two points, a beginning and an ending Two points, a beginning and an ending point.point.
The more complex the line, the more The more complex the line, the more points we will need to indicate exactly points we will need to indicate exactly where it is located.where it is located.
AREASAREAS
Objects observed closely enough to be Objects observed closely enough to be clearly seen to occupy both length and clearly seen to occupy both length and width are called areas.width are called areas.
Two-dimensional objects include the area Two-dimensional objects include the area occupied by a yard, the areal extent of a occupied by a yard, the areal extent of a city, and an area as large as a continentcity, and an area as large as a continent..
SURFACESSURFACES
Adding the dimension of height to our Adding the dimension of height to our area features allows us to observe and area features allows us to observe and record the existence of surfaces.record the existence of surfaces.
Surfaces occur all around us as natural Surfaces occur all around us as natural features. Hills, valleys, ridges, cliffs.features. Hills, valleys, ridges, cliffs.
Continuous dataContinuous data
SPATIAL MEASUREMENT LEVELSSPATIAL MEASUREMENT LEVELS
Objects themselves are called entities Objects themselves are called entities (coordinates)(coordinates)
Spatial features or entities also have Spatial features or entities also have additional information besides spatial additional information besides spatial informationinformation
The additional non-spatial information The additional non-spatial information that helps us describe the objects we that helps us describe the objects we observe in space comprises the feature’s observe in space comprises the feature’s attributes attributes
GEOGRAPHIC DATA GEOGRAPHIC DATA MEASUREMENTSMEASUREMENTS
Range from simply naming objects, to give Range from simply naming objects, to give ourselves something to call them, to ourselves something to call them, to precise measurements that allow us to precise measurements that allow us to directly compare the qualities of different directly compare the qualities of different objects.objects.
Nominal Scale: Named data, no Nominal Scale: Named data, no comparisoncomparison
GEOGRAPHIC DATA GEOGRAPHIC DATA MEASUREMENTSMEASUREMENTS
Ordinal Scale: From best to worst. The Ordinal Scale: From best to worst. The spectrum is based entirely on what we spectrum is based entirely on what we intended to use the information for.intended to use the information for.
Interval scale: Numbers are assigned to Interval scale: Numbers are assigned to the items measured.the items measured.
Ratio scale: Most useful, level of data Ratio scale: Most useful, level of data measurement. Allows us to make a direct measurement. Allows us to make a direct comparison between two spatial comparison between two spatial variablesvariables..
SPATIAL LOCATION AND SPATIAL LOCATION AND REFERENCESREFERENCES
Absolute location: It will give us definitive, Absolute location: It will give us definitive, measurable, fixed point in space.But we measurable, fixed point in space.But we must have a reference system against must have a reference system against which to evaluate such a location.which to evaluate such a location.
Spherical grid system, places two sets of Spherical grid system, places two sets of imaginary lines around the earthimaginary lines around the earth
SPATIAL LOCATION AND SPATIAL LOCATION AND REFERENCESREFERENCES
Parallels Parallels
The angular distance-The angular distance-llatitudeatitude
Meridians Meridians
TThe angular distance-he angular distance-longitudelongitude
GRAPHIC DATAGRAPHIC DATA
RASTERRASTER rasterraster grid cellsgrid cells resolutionresolution dots or pixeldots or pixel coveragecoverage grid, grid, compact storing of compact storing of
raster dataraster data
VECTORVECTOR X and Y coordinatesX and Y coordinates representative of representative of
dimensionalitydimensionality simple networksimple network topologytopology PolygonPolygon direct translation of direct translation of
the graphicthe graphic topologically coded topologically coded
network and polygonnetwork and polygon
NON GRAPHIC DATANON GRAPHIC DATA
SIMPLE LISTSIMPLE LIST Simplest file structure is called simple Simplest file structure is called simple
list.list. Our names, addresses like creating a Our names, addresses like creating a
separate index card for each name separate index card for each name (unordered)(unordered)
Searching is very inefficient (Suppose Searching is very inefficient (Suppose your database contains 200000 records)your database contains 200000 records)
ORDERED SEQUENTIAL FILESORDERED SEQUENTIAL FILES
The sequence of alphabetical characters.The sequence of alphabetical characters. Names and addresses in ordered files.Names and addresses in ordered files.
INDEXED FILESINDEXED FILES
It can be developed as direct files or It can be developed as direct files or inverted filesinverted files
Key attribute say a number sequence or Key attribute say a number sequence or alphabetic sequence. Search was based alphabetic sequence. Search was based on the key attributes ‘yellow pages’on the key attributes ‘yellow pages’
Attributes are the primary search criteria Attributes are the primary search criteria and the entities rely on them for selection. and the entities rely on them for selection. We call this an indexed inverted file We call this an indexed inverted file structurestructure
DATABASEDATABASE
A collection of multiple files is called A collection of multiple files is called database. The complexity of working with database. The complexity of working with database system requires a more database system requires a more elaborate structure for management elaborate structure for management called data base management system.called data base management system.
Hierarchical data structuresHierarchical data structures network systemnetwork system relational database structurerelational database structure
HIERARCHICAL DATA HIERARCHICAL DATA STRUCTURESTRUCTURE
Parent-to child branchingParent-to child branching classifying plants and animalsclassifying plants and animals A major advantages of this system is that A major advantages of this system is that
it is easy to search because the structure it is easy to search because the structure is so well defined and easy to expandis so well defined and easy to expand
NETWORK SYSTEMSNETWORK SYSTEMS
This structure allows users to move from This structure allows users to move from data item to data item through a series of data item to data item through a series of pointerspointers
network systems are generally considered network systems are generally considered to be an improvement over hierarchical to be an improvement over hierarchical structures for GIS work because they are structures for GIS work because they are less rigid and can handle many to many less rigid and can handle many to many reletionshipsreletionships
RELATIONAL DATABASE RELATIONAL DATABASE MANAGEMENT SYSTEMMANAGEMENT SYSTEM
The data are stored as ordered records or The data are stored as ordered records or rows of attribute values called tuplesrows of attribute values called tuples
Tubles are grouped with data rows in Tubles are grouped with data rows in aform collectively called relationsaform collectively called relations
primary keyprimary key relational joinrelational join graphic representation of entities and graphic representation of entities and
attributesattributes