Chap1 introduction to geographic information system (gis)
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GIS is a tool that allows for the storage, manipulation, retrieval, analysis and display of spatially referenced data. It differs from automated cartography and CAD in that it adds analytical capabilities. A LIS is a type of GIS focused on land information systems at a large scale. The main components of a GIS are people, data (spatial and aspatial), hardware, and software. The internet has greatly impacted GIS by facilitating data sharing, online discussions, and access to web-based GIS applications.
Chap1 introduction to geographic information system (gis)
- 1. Introduction to Geographic Information System (GIS) By: Dr. Mohamed Yagoub Mohamed E-mail: [email protected] URL: http://www.angelfire.com/mo/yagoub
- 2. Introduction to Automated Geography Chapter 1 DeMers, M. N. ,1997. Fundamental of Geographic Information Systems, John Wiley & Sons. Inc, New York
- 3. Objectives Define what a GIS is Development of GIS GIS, CAC, and CAD Analytical capabilities of GIS Analog mapping vs. automated GIS
- 4. What is GIS? Tools that allow for the processing of spatial data into information Not a precise or comprehensive definition Lack of definition results in misconceptions about GIS i.e., CAC, CAD and GIS are all the same – CAC -Computer Assited Cartography: create maps from graphical objects combined with descriptive attributes (size, color), lacks analytical capability – CAD -Computer Aided Design: create maps from graphical objects (no attributes)-Architecture – GIS - Adds the analytical capabilities the other 2 lack
- 5. What is GIS? GIS is any computerized information system that is designed to store, manipulate, retrieve, analyze, and display spatially referenced data. Land Information System (LIS) is typical to GIS, but related primarily to large scale and parcel-based system such as Automated Mapping and Facilities Management (AM/FM)
- 6. What is GIS? The major difference between Computer Mapping System (CMS), Computer Aided Design (CAD), and GIS is that the latter performs functions related to cartography (graphic) while the former has additional component of data analysis (graphic+ attribute)
- 7. Taxonomic classification of GIS (Fig. 1.1) 1. Spatial vs. nonspatial information GIS is spatial 2. Nongeographic vs. geographic (GIS) nongeographic - deals with geographic space but not geocoded 3. Other GIS vs. LIS Other GIS - nonland - economic, housing, market analysis LIS - most often used type of GIS - management and analysis of land surfaces 4. Non-parcel vs. parcel non-parcel - natural resource management, habitat evaluation, scientific investigation parcel - land ownership (cadastral)
- 8. GIS Development 1960s Computing comes of age 1970s GIS software evolves rapidly 1980s GIS software advances significantly Personal computers introduced Public domain data becomes available 1990s Application development 2000 Web-based GIS
- 9. Information system Information System (IS) Spatial IS (x,y,z,t) Non-spatial IS e.g. accounting Parcel-based (LIS) Other e.g. Forest (GIS)
- 10. Disadvantages of the manual methods Long time for processing Subject to human errors Data can not be managed efficiently Low cost/benefit ratio
- 11. Why GIS: Advantages of GIS Time minimization Accuracy improvement Data can be managed efficiently High cost/benefit ratio
- 12. Watersheds Communities Neighborhoods Ecosystems Context and Content Patterns Linkages Trends Seeing the WholeSeeing the Whole Managing PlacesManaging Places
- 13. GIS web sites www.gislinx.com -100s GIS sites www.esri.com -ESRI site www.tandf.co.uk -IJGIS journal www.amazon.com -GIS references http://www.iupui.edu/~jeswilso/g438/ DeMers http://www.csupomona.edu/~sagarver/GEO442/clas ssched.htm DeMers http://www.people.virginia.edu/~dc9a/classes/class es.html Exercise-DeMers http://www.utexas.edu/depts/grg/gcraft/about/tgis/t able1.html Geographer's Craft project
- 15. People People are essential part of GIS Issues related to people are training, education, management, law, security, data sharing and coordination GIS budget (cost of data, hardware, software, and maintenance)
- 16. 07/02/15 Hardware Input (Keyboard, mouse, digitizer, scanner, sound) Processing (Central processing unit -CPU) Pentium II (400 MHz) Storage (Magnetic and optical media -Hard disk 4GB, CD-ROM-650MB, Floppy 1.4 MB, Zip 100 MB) Output (Screen, sound system, printer, plotter) www.hp.com, www.calcomp.com
- 17. Hardware
- 19. Networking Wide Area Network (WAN) Remote
- 20. Software Operating System (OS) - WindowsY2K/NT Graphic software (CAD, Microstation) Database software (dBASE, Oracle) Statistical packages (SPSS, SAS, Minitab) Word processing (Ms Word, Word Perfect) Image processing (IDRISI, ER Mapper) GIS systems (Arc/Info, ArcView, MapInfo) Presentation (Ms PowerPoint, Coral Draw)
- 21. Software integration DXF IAC DDERELATE MS Visual Fox Pro AutoCad ARC/INFO ArcView Visual BasicVisual MODFLOW ODE
- 22. Selection of a GIS system Selection of a GIS systems depends on many factors e.g. the budget, purpose, and functions of the system For small companies and educational institutions, low cost systems are suitable e.g. ArcView and IDRISI For big companies a GIS system that provides multi-functions is necessary this may be at a high cost e.g. Arc/Info NT 8.0
- 23. Information There are two basic types of map information in a GIS: Spatial and Aspatial (DESCRIPITIVE-attribute) Spatial refers to geographic features that are represented as POINTS, LINES, and POLYGONS Aspatial or Descriptive refers to TABULAR DATA which records characteristics of the geographic features
- 24. GIS Information SPATIAL OBJECT ATTRIBUTE SPATIAL DBMS GIS Database (1) SPATIAL OBJECT ATTRIBUTE SPATIAL DBMS GIS Database (2)
- 25. d GIS is a tool to see the whole Social FactorsSocial Factors BiodiversityBiodiversity EngineeringEngineering Land UseLand Use EnvironmentalEnvironmental ConsiderationsConsiderations
- 26. 4 Sub-system definition of GIS (Tables 1.2-1.6) 1. A data input subsystem that collects and processes spatial data from various sources. 2. A data storage and retrieval subsystem that organizes data in a manner that allows retrieval, updating, and editing. 3. A data manipulation and analysis subsystem that performs tasks on the data (classification, modeling functions). 4. A reporting subsystem that displays all or part of the database in tabular, graphic or map form.
- 27. GIS functions Data acquisition (spatial and non-spatial) Data processing (data management) Data analysis (Spatial & statistical analysis) Data storage (Store data more efficiently) Data output (Maps, graphs, tables, reports)
- 28. Subsystem Definition of GIS Data Input Subsystem - allows user to import, create, and edit spatial and tabular data Data Storage and Retrieval Subsystem - provides storage, retrieval, updating and editing capabilities Data Analysis Subsystem - provides to tools to examine characteristics of the data and model building capabilities Reporting Subsystem - provides tools for designing maps, graphics, text, and tabular output
- 29. Data acquisition GIS includes Spatial and descriptive data (Attribute) Spatial data can be obtained from maps images or digital files Attribute data can be obtained from reports, statistical outcomes, and written documents
- 30. Data format The spatial data can be store in vector or raster format Vector format represents data in a series of (X,Y) coordinates Raster format represent data in a series of columns and rows-Matrix (Pixel, cell) Vector data are accurate and takes less storage, but take long time e.g. digitization Raster data are inaccurate and takes large storage, but takes short time e.g.
- 31. Coordinate system Sphere -Globe Three-Dimension Spherical coordinate Latitude (Ø) and longitude (λ) (Ø, λ) Plane-Map Two-Dimension Cartesian coordinate (X,Y) Distortion distance, area, shape, direction Map projections express 3D in 2D
- 32. Data processing Once the data is acquired the next step is to put it in a digital format. Data processing may include conversion of the data to a common coordinate system. Checking the accuracy of the spatial and attribute data Linking the spatial and attribute data
- 33. Data analysis Analysis is considered as the most important tool in GIS (Heart of GIS) . Spatial and statistical analysis can be done. Spatial analysis includes map overlay, buffering, and map algebra Statistical analysis includes e.g. determination of maximum, minimum, and average values New data can be derived from existing data
- 34. Soil Types + Crop Productivity (bushels/acre) Combined Layers When data coundaries betwen layers don’t match, the layers can be joined, creating a new layer containing the characteristics of both Data analysis : Data layers can be joined to create new layers containing the characteristic of both
- 35. Data storage GIS data can be store in different media. For example, Magnetic or optical media e.g. HD, floppy, and CD-ROM. Backup of GIS data must be done on regular basis to a void loss of data due to hardware failure, virus, or data corruption. Security measures must be taken e.g. at computer level (access right) and physical level (good locking and guard)
- 36. Data output: Visualization Output from GIS can be in hardcopy or softcopy and in different formats. Maps (2D, 3D) showing location and description. Tables showing detailed description. Reports showing summary of information. Different forms of graphs including bar, pie, and line.
- 37. Spatial data acquisition There are two methods for spatial data acquisition Primary methods Surveying, Photogrammetry, GPS, and Remote Sensing Secondary methods Digitization, Automatic line following, and scanning
- 38. Aspatial: Tabular Databases Tabular data (attribute, descriptive data) are essential part of GIS Attribute data can be obtained from reports or written documents Different database systems can be used for attribute input e.g. dBASE, Oracle, Informix Most database systems are based on arranging attribute data in a form of tables, these tables consists of fields and records
- 40. Database operations Databases allow users to build, sort, delete, edit, select, mathematically manipulate, and update information through the use of a Data Definition Language (DDL) and data manipulation Language (DML) DML (query language) allows users to ask questions about the database in a standardized way (Structured Query Language-SQL) e.g. find all states with area > 5000 sq Km
- 41. Standards for GIS Open GIS consortium (OGC) started in 1995 (OLE/COM) Eurog (developed in Europe) Spatial Data Transfer Standards (STDS) developed in the US
- 42. Impact of the Internet on GIS Exchange and Sharing of ideas via- electronic mail (e-mail) and online lists Online forum (video conferencing) Data transfer (File Transfer Protocol- FTP) Browsing (web sites)
- 43. GIS Applications Foresters - timber inventory Fire, police, ambulance - 911 and emergency vehicle routing Military - logistics and battle plans Telecommunications - siting cellular transmission towers Local to national scale government - city planning, zoning, natural resources, etc. Academia - used by many other disciplines outside of geography
- 44. Exercise 1 Principles of GIS
- 45. Section A: Principles of GIS Maximum 5 pages 1. Define GIS 2. What is the difference between automated cartography and GIS 3. What is the difference between GIS and LIS 4. Discuss briefly the main components of GIS( People, Data, Hardware, and Software) 5. Write one page about the impact of internet on GIS 6. List five web sites that you have visited
Editor's Notes
- #15: ## * * 07/16/96