Presentation on theme: "GIS Program 6th GIS Workshop"— Presentation transcript:
1 GIS Program 6th GIS Workshop Introduction to ArcGISGIS CONCEPTEng. Hussain DarwishTechnical College-Baghdad
2 Geographic Information Systems Eng.Hussain DarwishTechnical College-Baghdad
3 A Generic Definition of GIS Geographic = spatially referenced dataInformation = data processed into a usable formSystem = a framework for manipulating, analyzing and presentation of information
4 What is a Geographic Information System (GIS)? A GIS is an organized collection of computer hardware, software, geographic data, and people, to efficiently capture, store, update, manipulate, analyze, and display all forms of geographically referenced information.A GIS is both a database system with specific capabilities for spatially-reference data, as well [as] a set of operations for working with data In a sense, a GIS may be thought of as a higher-ordermap.”
6 GIS requirements 1. Data input, from maps, aerial photos, satellites, surveys, GPS, and othersources2. Data storage, retrieval, and query3. Data transformation, analysis,and modeling, including spatialstatistics4. Data representation (reporting), such as maps,reports, and plans
7 Basic Questions Askedwith a GIS:• What is at..._____? (Location)• Where is it..._____? (Condition)• What has changed...? (Trend)• Which is the best way...? (Routing)• What is the pattern...? (Pattern)• What if...? (Modeling)
8 What is a Geographic Information System (GIS)? An information system has a full range of functions to:process observationsprocess measurementsprovide descriptionsexplain datamake decisions
9 Convert Data to Digital Format GIS ProcessCapture DataRegister Map BaseInterpret DataStore Data in ComputerConvert Data to Digital FormatProcess DataDisplay Results
10 GIS DATASPATIAL (POSITIONAL) DATAATTRIBUTE (TABULAR) DATA
11 GIS System Spatial Data Base Attribute Data Base Cartographic Display SystemGeographic Analysis SystemMap Digitizing SystemImage Processing SystemStatistical Analysis SystemDatabase Management SystemImagesMapsStatistical ReportsStatistics Tabular DataGIS System
12 GIS Data Format Raster data Vector data There are two formats used by GIS systems to store and retrieve geographical data:Raster dataVector data
13 Spatial Data Model: Basic Data Format GIS are driven by spatial dataTwo basic spatial (coordinate/geometric) data existVector: based on geometry ofpointslinespolygonsRaster: based on geometry ofgrid cells (images, bitmaps, DEMs)_
14 Raster Format Data are divided into cell, pixels, or elements Cells are organized in arraysEach cell has a single valueRow and Column Numbers are used to identify the location of the cell within the array.Perhaps the most common example of raster data is a digital image.
15 Vector FormatData are associated with points, lines, or boundaries enclosing areas (polygons)Points are located by coordinatesLines are described by a series of connecting vectors (line segments described) ,by the coordinates of the start and end pointAreas or polygons are described by a series of vectors enclosing the area.
16 Vector FormatAny number of factors or attributes can be associated with a point line or polygon.Data are stored in two files:a file containing location informationa file containing information on the attributesA third file contains information needed to link positional data with their attributes.
17 GIS Data Types Features Surfaces Networks Point datasets Line datasets Polygon datasetsSurfacesGrid datasetsTIN datasetsImages datasetsNetworksSimple denstritic networksSimple loop networks
18 Vector and Raster Representation of Point Map Features GIS Vector FormatGIS Raster Format(X,Y) Coordinate in spaceCell Located in an Array row and column
19 Point FeaturesAll points required to define the feature geometry have to be stored as part of the feature definition.
20 Point Features Point datasets One-to-one relation between features in the map and records in the table.
21 Vector and Raster Representation of Line Map Features GIS Vector FormatGIS Raster Format
22 Line Features Line datasets One-to-one relation between features in the map and records in the table.
23 Vector and Raster Representation of Area Map Features GIS Vector FormatGIS Raster Format
24 Area Features Polygon datasets One-to-one relation between features in the map and records in the table.
26 Data Structure of Surfaces Grid datasets:Cellular-based data structure composed of square cells of equal size arranged in rows and columns.Grid definition requires: (1) the coordinates of the upper-left corner, (2) the cell size, (3) the number of rows, (4) the number of columns, and (5) the value at each cell.Cells that do not store any value are called NODATA cells.Number of columnsNumber of rowsCell size(x, y)
28 Data Structure of Surfaces Triangular Irregular Network (TIN) Datasets:Dataset constructed by connecting points -- for which the TIN parameter is known – forming triangles.Triangle sides are constructed by connecting adjacent points so that the minimum angle of each triangle is maximized.Triangle sides cannot cross breaklines.The TIN format is efficient to store data because the resolution adjusts to the parameter spatial variability.
29 Data Structure of Surfaces Triangular Irregular Network (TIN) Datasets
31 Data Structure of Surfaces Image datasets:ARC Digitized Raster Graphics (ADRG)Windows bitmap images (BMP) [.bmp]Multiband (BSQ, BIL and BIP) and single band images [.bsq, .bil and bip]ERDAS [.lan and .gis]ESRI Grid datasetsIMAGINE [.img]IMPELL Bitmaps [.rlc]Image catalogsJPEG [.jpg]MrSID [.sid]National Image Transfer Format (NITF)Sun rasterfiles [.rs, .ras and .sun]Tag Image File Format (TIFF) [.tiff, .tif and .tff]TIFF/LZW
34 Data Structure of Features NodesVerticesA line is an open sequence of points in which the first and last points are called nodes, and the remaining intermediate points are called vertices.
35 Data Structure of Features Complex linesSimple lines
36 Data Structure of Features Complex polygonsSimple polygons
37 Data Structure of Features Not space-filling polygonsSpace-filling polygons
38 Data Structure of Features BAD12345IIIIIILine and polygon topology
39 Data Structure of Networks Simple loop networks:System of simple lines -- called links -- connected at their nodes.Links can point in either direction or in both directions.ABEIJKDCGH1F23456789101112
40 Vector and Raster Formats Most GIS software can display both vector and raster data.Raster formats are efficient when comparing information among arrays with the same cell size.Raster files are generally very large because each cell occupies a separate line of data.Vector formats are efficient when comparing information whose geographical dimensions are different.
41 Vector Data ModelMajor types (formats) of vector data available in ArcGISESRI GeoDatabasesESRI shapefilesArcInfo coverages and librariesCAD files (AutoCAD DWG, DXF; Microstation DGN)StreetMap filesSpatial Database Engine (SDE) dataASCII point coordinate dataLinear measure (route) data_
42 Vector Data Model Characteristics of the vector data model: + Features are positioned accurately+ Shape of features can be represented correctly+ Features are represented discretely (no fuzzy boundaries)– Not good for representing spatially continuous phenomena– Potentially complex data structure (especially for polygons); can lead to long processing time for analytical operations_
43 Raster Data Model Raster spatial data model origin is set explicitly cell size is always knowncell references (row/column locations) are knowncell values are referenced to row/column locationvalues represent numerical phenomena or index codes for non-numerical phenomena_
44 Raster Data Model Characteristics of the raster data model: Rectangular grid of square cellsShape of discrete polygonal features generalized by cellsContinuous (surface) data represented easilySimple data structure_
45 Raster Data ModelRaster data are good at representing continuous phenomena, e.g.,Elevation, slope, aspectSoil types.Electromagnetic reflectance (photographic or satellite imagery)Radar images.Continuous phenomena
46 Comparison of Raster and Vector Formats Raster formats are efficient when comparing information among arrays with the same cell size.Raster files are generally very large because each cell occupies a separate line of data, only one attribute can be assigned to each cell, and cell sizes are relatively small.Vector formats are efficient when comparing information whose geographical shapes and sizes are different.Vector files are much smaller because a relatively small number of vectors can precisely describe large areas and a many attributes can be ascribed to these areas.
47 Comparison of Raster and Vector Formats Raster representations are relatively coarse and impreciseVector representations of shapes can be very precise.Most GIS software can display both raster and vector data. Only a limited number of programs can analyze both types of data or make raster type analyses in vector formats.
48 Attributes data Types of Attributes data Numeric data ( e.g. size, area, temperature,…etc.).Semantic data (e.g. class, type, name, quality…etc.).Each of them may be stored in a coded manner.
49 Relational Database Model & Attribute Data Structures The “where” of GIS is determined by coordinate (map) data structures, but …The “what” of GIS is determined by tabular (relational database) data structuresThus, tabular data are just as important as coordinate data.
50 Relational Database Model & Attribute Data Structures Attribute data are stored in database tables.Tables are composed of:fields (columns)andrecords (rows)_
51 Relational Database Model & Attribute Data Structures Each vector data source has an attribute table
52 Relational Database Model & Attribute Data Structures You may already be familiar with some types of relational databasesdBaserBaseMS AccessMS Excel (database functionality)Oracle, INFORMIX, INGRES, SQL ServerMySQL, PostgreSQLINFO (in ArcInfo)_
53 Relational Database Model & Attribute Data Structures Tables can be linked and joined (“related”) by use of common values in fields
54 Relational Database Model & Attribute Data Structures Different types data that may have attribute tables in ArcGISVectorpoint attributepolygon attributeline attributenode attribute*text attribute*route & event*CAD attributesRastervalue attribute tables*_* in ArcInfo coverage & grid data only
55 What is a Geographic Information System (GIS)? In a geographic information system, information is characterized spatially.In a GIS the common purpose is decision making to manage:landresourcestransportationOR any other spatially distributed activity
56 GIS APLLICATIONExamples of application of automated methods include a wide range: engineering mining natural resource management agriculture planning (all gov’t levels) etc...
57 GIS Application… but generally can be grouped into four basic categories:NATURAL RESOURCE MANAGEMENTForest & WildlifeHydrologicalMineralsURBAN & REGSIONAL MANAGEMENTLand Use Planning/Environmental ImpactPublic WorksEmergency ResponseLegal RecordsTransportation and network management
58 GIS Application COMMERCIAL Market Area Analysis Site Selection Routing AGRICULTURAL MANAGEMENTField RecordsAnimal ManagementClimate Change / Human Impact
59 History of GIS Decade Milestones for computer-based GIS 1960’s Canada Geographic Information System (CGIS) developed: national land inventory pioneered many aspects of GISHarvard Lab for Computer Graphics and Spatial Analysis: pioneered software for spatial data handlingUS Bureau of Census developed DIME data formatESRI founded1970’sCGIS fully operational (and still operational today)-First Landsat satellite launched (USA)-First geocoded census-USGS begins Geographical Information Retrieval and Analysis System (GIRAS) to manage and analyze large land resources databases and Digital Line Graph (DLG) data format-ERDAS founded-ODYSSEY GIS launched (first vector GIS)
60 History of GIS Decade Milestones for computer-based GIS 1980’s -ESRI launches ARC/INFO (vector GIS)-GPS became operational-US Army Corp of Engineers develop GRASS (raster GIS)-MapInfo founded-Burrough’s book on “Principles of [GIS] for Land Resources Assessment” published-First SPOT satellite launched (Europe)-Idrisi Project started (GIS program)-SPANS GIS produced-National Center for Geographic Information and Analysis (NCGIA) established in USA-first release of US Bureau of the Census TIGER digital data products
62 Major GIS-Only Journals International Journal of Geographical Information SystemsGeographical SystemsTransactions in GISGeo Info SystemsGIS World
63 ArcView Basics Project (the foundation. Contains the documents) Views LayoutsViewsThemescompile maps for printingdisplay and query spatial data.contains multiple themes (i.e. layers of data).the actual data.Contains geographical features of the same kind (points, lines or polygons) and their attributesTablescontain the attribute data of a themeScriptsCharts
64 Introduction to GIS (1) Four basic steps for map production Data CollectionData Display / ExploreData AnalysisMap Composition
65 .. Map Characteristics In addition to feature locations and their attributes, the other technical characteristics that define maps and their use includes:Map ScaleMap AccuracyMap Extent andData Base Extent
66 Fundamentals of GISMapping Concepts, Features & Properties A map represents geographic features or other spatial phenomena by graphically conveying information about locations and attributes. Locational information describes the position of particular geographic features on the Earth's surface, as well as the spatial relationship between features, such as the shortest path from a fire station to a library, the proximity of competing businesses, and so on. Attribute information describes characteristics of the geographic features represented, such as the feature type, its name or number and quantitative information such as its area or length. Thus the basic objective of mapping is to providedescriptions of geographic phenomenonspatial and non spatial informationmap features like Point, Line, & Polygon
67 Map FeaturesMap Features Locational information is usually represented by points for features such as wells and telephone pole locations, lines for features such as streams, pipelines and contour lines and areas for features such as lakes, counties and census tracts. Point feature A point feature represents as single location. It defines a map object too small to show as a line or area feature. A special symbol of label usually depicts a point location. Line feature A line feature is a set of connected, ordered coordinates representing the linear shape of a map object that may be too narrow to display as an area such as a road or feature with no width such as a contour line. Area feature An area feature is a closed figure whose boundary encloses a homogeneous area, such as a state country soil type or lake
68 Where GIS is being Applied l: Urban Planning, Management & PolicyZoning, subdivision planningLand acquisitionEconomic developmentCode enforcementHousing renovation programsEmergency responseCrime analysisTax assessment
69 Where GIS is being Applied: II Environmental SciencesMonitoring environmental riskModeling storm water runoffManagement of, floodplains, wetlands, forests.Environmental Impact AnalysisGroundwater modeling and contamination tracking
70 Where GIS is being Applied: III Political ScienceRedistrictingAnalysis of election resultsPredictive modelingCivil Engineering/UtilityLocating underground facilitiesDesigning alignment for freeways, transitCoordination of infrastructure maintenance
71 Where GIS is being Applied: IV BusinessDemographic AnalysisMarket Penetration/ Share AnalysisSite SelectionEducation AdministrationAttendance Area MaintenanceEnrollment ProjectionsSchool Bus Routing
72 Where GIS is being Applied: IV Real EstateNeighborhood land pricesTraffic Impact Analysis
74 Summery GIS As A Set Of Interrelated Subsystems: 1. Spatial and Attribute Data Base2. Cartographic Display System3. Map Digitizing System4. Database Management System5. Geographic Analysis System6. Image Processing System7. Statistical Analysis System8. Decision Support System