Geographical information systems GIS 2008 Enviromatics 2008 Geographical

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

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 2

Introduction (2) • The integration of thematic data and information about the spatial situation (which will be presented cartographical), distinguishes a GIS from a mere cartographic- or CAD(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 3

Other definitions for GIS • The common ground between information processing and the many fields using spatial analysis techniques (Tomlinson, 1972). • A powerful set of tools for collecting, storing, retrieving, transforming, and displaying spatial 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 system with specific capabilities for spatially referenced data, as well as a set of operations or working with the data (Star and Estes, 1990). Enviromatics 2008 - Geographical information systems GIS 4

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 5

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 6

Visualization of Data Enviromatics 2008 - Geographical information systems GIS 7

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

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

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. Different issues are connected by their geographic position. Enviromatics 2008 - Geographical information systems GIS 10

Steps in a GIS project 1. Data acquisition (paper maps, digital files, remote sensing data, satellite data, field work), 2. Data preprocessing (preparation, integration, data conversion, digitising and/or scanning, edge matching, rectification), 3. Data management (variable selection, data definition, table design (performance, usability), CRUD policies/procedures (create: data entry; retrieve: view; update: change; delete: remove)), 4. Manipulation and analysis (address matching, network analysis, terrain modelling: slopes, different aspects), 5. Product generation (tabular reports, graphics: maps, charts). Enviromatics 2008 - Geographical information systems GIS 11

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 given distance to another object ? ) • the spatial modelling of complex scenarios (risk analysis, route planning, resource management) Enviromatics 2008 - Geographical information systems GIS 12

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

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

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

Data Models Enviromatics 2008 - Geographical information systems GIS 16

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

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

Vector GIS Objects Enviromatics 2008 - Geographical information systems GIS 19

Atributes Enviromatics 2008 - Geographical information systems GIS 20

Selecting objects Enviromatics 2008 - Geographical information systems GIS 21

Selecting Enviromatics 2008 - Geographical information systems GIS 22

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

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

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

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 26

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

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 28

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

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

3 Combination of grid model (surface) and vector model (houses) Enviromatics 2008 - Geographical information systems GIS 31

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

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

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

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. Property maps, air photos). • tying data to maps permits the succinct communication of complex spatial patterns (e. g. environmental sensitivity). • providing answers to spatial queries. • performing complex spatial modelling (e. g. scenarios for transportation planning, disaster planning, utility design, risk modelling). Enviromatics 2008 - Geographical information systems GIS 35

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

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 spatial data, low cost and consistent update of input data), • Photogrammetry (source of most data on topography used in GIS, uses aerial 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 37

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 understand issues of error and uncertainty in GIS data), • Operations research (optimising techniques used in GIS applications such as routing), • Computer Science (GIS uses computer aided design (CAD) technologies, computer graphics and visualisation, DBMS). Enviromatics 2008 - Geographical information systems GIS 38

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

Software for GIS (2) • Graphic Data Systems (Originated as Mc. Donnel-Douglas inhouse system, industrial applications, visualisation of technical products, now mapping the environment) • ERDAS/Imagine, ER MAPPER, PCI, Envi (Origins in remote sensing raster and 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, but 1996 end of development and support announced), • SICAD (Comparable with Arc. Info, powerful GIS with a lot of functionalities for raster and vector data, object oriented database) • IDRISI (Comparable with Arc. Info, but not so powerful), • Map. Info (Small GIS, useful for planning purposes, easy to handle) Enviromatics 2008 - Geographical information systems GIS 40

Problems in GIS practice Up to now, there is no system that could solve all possible tasks a GIS normally is 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 41

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

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

Hydro-Modeling Enviromatics 2008 - Geographical information systems GIS 44

Flow direction Enviromatics 2008 - Geographical information systems GIS 45

Flow accumulation Enviromatics 2008 - Geographical information systems GIS 46

sub-catchments Enviromatics 2008 - Geographical information systems GIS 47

Questions? Enviromatics 2008 - Geographical information systems GIS 48