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Geographical information systems (GIS)

Geographical information systems (GIS). Вонр. проф. д-р Александар Маркоски Технички факултет – Битола 2008 год. Introduction. “A computer based system, consisting of hardware, software, data and application. It provides scientific information considering spatial relation.

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Geographical information systems (GIS)

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  1. Geographical information systems(GIS) Вонр. проф. д-р Александар Маркоски Технички факултет – Битола 2008 год. Enviromatics 2008 - Geographical information systems GIS

  2. Introduction “A computer based system, consisting of hardware, software, data and application.It provides scientific information considering spatial relation. A GIS has to offer functions for • input, • storage, • checkup, • manipulation, • integration, • analyzing and • alphanumeric as well as graphic presentation of spatial data. Enviromatics 2008 - Geographical information systems GIS

  3. Introduction (2) • The integration of thematic data and information about the spatial situation (which willbe presented cartographical), distinguishes a GIS from a mere cartographic- orCAD-(Computer Aided Design) system.” (Weidenbach, 1999) • GIS is not only a tool for making maps, it is a system for data analysis! Enviromatics 2008 - Geographical information systems GIS

  4. Other definitions for GIS • The common ground between information processing and the many fields usingspatial analysis techniques (Tomlinson, 1972). • A powerful set of tools for collecting, storing, retrieving, transforming, and displayingspatial data from the real world (Burroughs, 1986). • A computerized database management system for the capture, storage, retrieval,analysis and display of spatial data (NCGIA, 1987). • An information system that is designed to work with data referenced by spatialor geographic coordinates. In other words, a GIS is both a database systemwith specific capabilities for spatially referenced data, as well as a set of operationsor working with the data (Star and Estes, 1990). Enviromatics 2008 - Geographical information systems GIS

  5. Тerm GIS The term GIS has different meanings. Depending on the focal point it is: • a collection of spatial data • a collection of tools • a package of hard- and software components • a technology Enviromatics 2008 - Geographical information systems GIS

  6. Contributions to GIS-development • Informatics (graphic, visualization, data base, security, system administration), • geography and related fields (cartography, geodesy, geomorphology, spatial statistics) • user(public administration, engineering, location search, planning, geology, mining, forestry, marketing, criminology) Enviromatics 2008 - Geographical information systems GIS

  7. Visualization of Data Enviromatics 2008 - Geographical information systems GIS

  8. Elements of a GIS Enviromatics 2008 - Geographical information systems GIS

  9. The four-components-model of a GIS Enviromatics 2008 - Geographical information systems GIS

  10. Which Operations can be done with a GIS ? • What is where? • Where is what? • What has changed since...? • How is the spatial spread? • What happens if...? GIS uses the spatial allocation as a common key for different data records. Differentissues are connected by their geographic position. Enviromatics 2008 - Geographical information systems GIS

  11. Steps in a GIS project • Data acquisition (paper maps, digital files, remote sensing data, satellitedata, field work), • Data preprocessing (preparation, integration, data conversion, digitisingand/or scanning, edge matching, rectification), • Data management (variable selection, data definition, table design (performance,usability), CRUD policies/procedures (create: data entry; retrieve:view; update: change; delete: remove)), • Manipulation and analysis (address matching, network analysis,terrainmodelling: slopes, different aspects), • Product generation (tabular reports, graphics: maps, charts). Enviromatics 2008 - Geographical information systems GIS

  12. What should be possible with a GIS? • Management, analysis, connecting, presentation of geographic data allows: • automatic processing of geographic data, for example for making maps, • calculation of areas or distances • calculation of slopes, exposition direction or visibility analyses, • route planning, traffic management or logistics • integration of data of different origins and types • linkage of data to maps, to make complex spatial relations visible • to answer spatial questions (for example: How many objects are within a givendistance to another object ?) • the spatial modelling of complex scenarios (risk analysis, route planning, resourcemanagement) Enviromatics 2008 - Geographical information systems GIS

  13. System architecture and components Enviromatics 2008 - Geographical information systems GIS

  14. Data Models • What should a GIS represent? Enviromatics 2008 - Geographical information systems GIS

  15. Discrete Objects have attributes as length volume land use type ContinuousInformationfor an area has gradientsas : temperature content of water distribution of precipitation content of contaminants Data Models (2) Depending on the data concept there are raster/Grid-GIS or Vector-GIS. Systemsworking with both types, are named hybrid systems. Enviromatics 2008 - Geographical information systems GIS

  16. Data Models Enviromatics 2008 - Geographical information systems GIS

  17. General Structure of a Grid Enviromatics 2008 - Geographical information systems GIS

  18. Vector Data • The vector-structure is necessary for a object-related data management in GIS. It isused for the realization of topologic structures and complex data models. • Objects inVector-GIS are points, lines, polygons. • Every GIS-object in a view has a representation in the data base. The attributes describethe objects and allow selections and classifications. • Classification by attribute (above) or selection by attribute (below) are typical DataBase Management Methods. Selection or classification by spatial relations are typicalGIS-methods. Enviromatics 2008 - Geographical information systems GIS

  19. Vector GIS Objects Enviromatics 2008 - Geographical information systems GIS

  20. Atributes Enviromatics 2008 - Geographical information systems GIS

  21. Selecting objects Enviromatics 2008 - Geographical information systems GIS

  22. Selecting Enviromatics 2008 - Geographical information systems GIS

  23. Vector vs. Raster Enviromatics 2008 - Geographical information systems GIS

  24. Raster vs. Vector Enviromatics 2008 - Geographical information systems GIS

  25. Representation of Vector Data as Raster Data Enviromatics 2008 - Geographical information systems GIS

  26. Modelling topography special features • Mass points and break lines from surveying, • Triangulated irregular networks (TIN), • 2,5-D Visualisation: Hillshading, • Colour coded digital terrain model (DTM), • 3-D Visualisation. Enviromatics 2008 - Geographical information systems GIS

  27. Grid data model • Digital Elevation Model (DEM) in the background, showing the elevation, usinggraduated colors and shadows for visualizing 3rd dimension. In the foregroundhouses and water body (river) are shown, using vector data model. Enviromatics 2008 - Geographical information systems GIS

  28. Triangulated Irregular Network • Base for developing the DEM (above) is a Triangulated Irregular Network (TIN), based on measured points Enviromatics 2008 - Geographical information systems GIS

  29. 1 3D-Presentation of a the same TIN, examplefor vector based representation of a surface • irregular size of triangles, • areas with higher and lower densityof knots Enviromatics 2008 - Geographical information systems GIS

  30. 2 3D-Presentation of a grid, showing the samearea (but different point of view) • regular cell size Enviromatics 2008 - Geographical information systems GIS

  31. 3 Combination ofgrid model (surface) andvector model (houses) Enviromatics 2008 - Geographical information systems GIS

  32. Example for high resolution grid Enviromatics 2008 - Geographical information systems GIS

  33. Example: Visualization of water quality data, using polygons Enviromatics 2008 - Geographical information systems GIS

  34. Example: Visualization of water quality data, using polygons (cont.) Enviromatics 2008 - Geographical information systems GIS

  35. Fields of applications of GIS • Automation of activities involving geographic data like map production,calculation of areas, distances or route lengths, measurement of slopes,aspect, view shed, logistics, route planning, vehicle traffic, traffic management,land use management, environmental planning, flood control,resource management, and others. • Integration of data hitherto confined to independent domains (e. g. Propertymaps, air photos). • tying data to maps permits the succinct communication of complexspatial patterns (e. g. environmental sensitivity). • providing answers to spatial queries. • performing complex spatial modelling (e. g. scenarios for transportationplanning, disaster planning, utility design, risk modelling). Enviromatics 2008 - Geographical information systems GIS

  36. Use of GIS in practical and researchfields • Environmental and resource management (Watershed management, soilconservation, air pollution control, agriculture, water harvesting, water supply), • Urban planning, management and policy (Land acquisition, environmentalimpact assessment), • Surveying, • Facility management (Infrastructure, telecommunication), • Transport, Traffic, Logistics, • Research and development (Environmental modelling, simulation and optimisationof energy, soil, water, climate, etc. for risk assessment and decision support). Enviromatics 2008 - Geographical information systems GIS

  37. Scientific and engineering contributors to GIS • Geography (provides techniques for conducting spatial analysis), • Cartography (maps have been a major source of information input for GIS,long tradition in map design which is an important output from GIS), • Remote sensing (images from air and space are major sources of spatialdata, low cost and consistent update of input data), • Photogrammetry (source of most data on topography used in GIS, usesaerial photographs for making accurate spatial measurements, IR photographs), • Surveying (provides high quality data on positions of land boundaries, buildings,etc.), Enviromatics 2008 - Geographical information systems GIS

  38. Scientific and engineering contributors to GIS (2) • Geodesy (high accuracy positional control for GIS, uses GPS technology), • Statistics (statistical techniques used in GIS analysis, important to understandissues of error and uncertainty in GIS data), • Operations research (optimising techniques used in GIS applications suchas routing), • Computer Science (GIS uses computer aided design (CAD) technologies,computer graphics and visualisation, DBMS). Enviromatics 2008 - Geographical information systems GIS

  39. Software for GIS • ArcInfo (Originated commercial GIS, clear market leader), • Intergraph (Strong in design and facilities mapping, running hard to matchArcInfo, its main modular GIS environment evolved from its older CAD products,development of a new generation product of ist own code named Jupiter basedon NT and object technology) • Bentley Systems (Originally developed the PC-based Micro-Station productGeoGraphics in cooperation with Bentley Systems, but split in 1995, have verysuccessfully continued to develop and sell MicroStation GeoGraphics) • Autodesk’s AutoCAD Map (Dominant CAD supplier and software company,fully topological AutoCAD Map since 1996, illustrates convergence of CAD/GIS,many industrial applications of AutoCAD for mapping) Enviromatics 2008 - Geographical information systems GIS

  40. Software for GIS (2) • Graphic Data Systems (Originated as McDonnel-Douglas in-house system,industrial applications, visualisation of technical products, now mapping the environment) • ERDAS/Imagine, ER MAPPER, PCI, Envi (Origins in remote sensing rasterand vector data, new satellite data products, ER MAPPER originating in Australia,PCI originating in Canada) • GRASS (Public domain software, raster oriented with some vector routines, but1996 end of development and support announced), • SICAD (Comparable with ArcInfo, powerful GIS with a lot of functionalities forraster and vector data, object oriented database) • IDRISI (Comparable with ArcInfo, but not so powerful), • MapInfo (Small GIS, useful for planning purposes, easy to handle) Enviromatics 2008 - Geographical information systems GIS

  41. Problems in GIS practice Up to now, there is no system that could solve all possible tasks a GIS normallyis confronted with: • there is no unique data model that serves well for all GIS applications, • there are no fully compatible geodata, • there are no scale-independent geodata, • there are no fully compatible/applicable commercial systems of data formatting, • there are still severe problems with data exchange, • there are some deficits in standardisation of GIS. Enviromatics 2008 - Geographical information systems GIS

  42. GIS Application Example:Hydrological Modelling using ArcView • 1. Creating a DEM from point data file • 2. Creating river network • 3. Creating sub-catchments and pour points Example is based on ArcView 3.x, with Spatial Analyst,3D-Analyst and Hydro-Modeling Extension Enviromatics 2008 - Geographical information systems GIS

  43. Creating a DEM from point data file Enviromatics 2008 - Geographical information systems GIS

  44. Hydro-Modeling Enviromatics 2008 - Geographical information systems GIS

  45. Flow direction Enviromatics 2008 - Geographical information systems GIS

  46. Flow accumulation Enviromatics 2008 - Geographical information systems GIS

  47. sub-catchments Enviromatics 2008 - Geographical information systems GIS

  48. Questions? Enviromatics 2008 - Geographical information systems GIS

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