GIS Program 6th GIS Workshop Introduction to ArcGIS GIS CONCEPT Eng. Hussain Darwish Technical College-Baghdad

Geographic Information Systems Eng.Hussain Darwish Technical College-Baghdad

A Generic Definition of GIS Geographic = spatially referenced data Information = data processed into a usable form System = a framework for manipulating, analyzing and presentation of information

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-order map.”

GIS COMPONENTES

GIS requirements 1. Data input, from maps, aerial photos, satellites, surveys, GPS, and other sources 2. Data storage, retrieval, and query 3. Data transformation, analysis, and modeling, including spatial statistics 4. Data representation (reporting), such as maps, reports, and plans

Basic Questions Asked with 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)

What is a Geographic Information System (GIS)? An information system has a full range of functions to: process observations process measurements provide descriptions explain data make decisions

Convert Data to Digital Format GIS Process Capture Data Register Map Base Interpret Data Store Data in Computer Convert Data to Digital Format Process Data Display Results

GIS DATA SPATIAL (POSITIONAL) DATA ATTRIBUTE (TABULAR) DATA

GIS System Spatial Data Base Attribute Data Base Cartographic Display System Geographic Analysis System Map Digitizing System Image Processing System Statistical Analysis System Database Management System Images Maps Statistical Reports Statistics Tabular Data GIS System

GIS Data Format Raster data Vector data There are two formats used by GIS systems to store and retrieve geographical data: Raster data Vector data

Spatial Data Model: Basic Data Format GIS are driven by spatial data Two basic spatial (coordinate/geometric) data exist Vector: based on geometry of points lines polygons Raster: based on geometry of grid cells (images, bitmaps, DEMs)_

Raster Format Data are divided into cell, pixels, or elements Cells are organized in arrays Each cell has a single value Row 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.

Vector Format Data are associated with points, lines, or boundaries enclosing areas (polygons) Points are located by coordinates Lines are described by a series of connecting vectors (line segments described) ,by the coordinates of the start and end point Areas or polygons are described by a series of vectors enclosing the area.

Vector Format Any number of factors or attributes can be associated with a point line or polygon. Data are stored in two files: a file containing location information a file containing information on the attributes A third file contains information needed to link positional data with their attributes.

GIS Data Types Features Surfaces Networks Point datasets Line datasets Polygon datasets Surfaces Grid datasets TIN datasets Images datasets Networks Simple denstritic networks Simple loop networks

Vector and Raster Representation of Point Map Features GIS Vector Format GIS Raster Format (X,Y) Coordinate in space Cell Located in an Array row and column

Point Features All points required to define the feature geometry have to be stored as part of the feature definition.

Point Features Point datasets One-to-one relation between features in the map and records in the table.

Vector and Raster Representation of Line Map Features GIS Vector Format GIS Raster Format

Line Features Line datasets One-to-one relation between features in the map and records in the table.

Vector and Raster Representation of Area Map Features GIS Vector Format GIS Raster Format

Area Features Polygon datasets One-to-one relation between features in the map and records in the table.

Surfaces Features Grid datasets

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 columns Number of rows Cell size (x, y)

Surfaces Features TIN datasets

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.

Data Structure of Surfaces Triangular Irregular Network (TIN) Datasets

Image Surface Features Image datasets

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 datasets IMAGINE [.img] IMPELL Bitmaps [.rlc] Image catalogs JPEG [.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

Networks Simple networks

Networks Simple loop networks

Data Structure of Features Nodes Vertices A 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.

Data Structure of Features Complex lines Simple lines

Data Structure of Features Complex polygons Simple polygons

Data Structure of Features Not space-filling polygons Space-filling polygons

Data Structure of Features B A D 1 2 3 4 5 I II III Line and polygon topology

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. A B E I J K D C G H 1 F 2 3 4 5 6 7 8 9 10 11 12

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.

Vector Data Model Major types (formats) of vector data available in ArcGIS ESRI GeoDatabases ESRI shapefiles ArcInfo coverages and libraries CAD files (AutoCAD DWG, DXF; Microstation DGN) StreetMap files Spatial Database Engine (SDE) data ASCII point coordinate data Linear measure (route) data_

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_

Raster Data Model Raster spatial data model origin is set explicitly cell size is always known cell references (row/column locations) are known cell values are referenced to row/column location values represent numerical phenomena or index codes for non-numerical phenomena_

Raster Data Model Characteristics of the raster data model: Rectangular grid of square cells Shape of discrete polygonal features generalized by cells Continuous (surface) data represented easily Simple data structure_

Raster Data Model Raster data are good at representing continuous phenomena, e.g., Elevation, slope, aspect Soil types. Electromagnetic reflectance (photographic or satellite imagery) Radar images. Continuous phenomena

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.

Comparison of Raster and Vector Formats Raster representations are relatively coarse and imprecise Vector 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.

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.

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 structures Thus, tabular data are just as important as coordinate data.

Relational Database Model & Attribute Data Structures Attribute data are stored in database tables. Tables are composed of: fields (columns) and records (rows)_

Relational Database Model & Attribute Data Structures Each vector data source has an attribute table

Relational Database Model & Attribute Data Structures You may already be familiar with some types of relational databases dBase rBase MS Access MS Excel (database functionality) Oracle, INFORMIX, INGRES, SQL Server MySQL, PostgreSQL INFO (in ArcInfo)_

Relational Database Model & Attribute Data Structures Tables can be linked and joined (“related”) by use of common values in fields

Relational Database Model & Attribute Data Structures Different types data that may have attribute tables in ArcGIS Vector point attribute polygon attribute line attribute node attribute* text attribute* route & event* CAD attributes Raster value attribute tables*_ * in ArcInfo coverage & grid data only

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: land resources transportation OR any other spatially distributed activity

GIS APLLICATION Examples of application of automated methods include a wide range: engineering mining natural resource management agriculture planning (all gov’t levels) etc...

GIS Application … but generally can be grouped into four basic categories: NATURAL RESOURCE MANAGEMENT Forest & Wildlife Hydrological Minerals URBAN & REGSIONAL MANAGEMENT Land Use Planning/Environmental Impact Public Works Emergency Response Legal Records Transportation and network management

GIS Application COMMERCIAL Market Area Analysis Site Selection Routing AGRICULTURAL MANAGEMENT Field Records Animal Management Climate Change / Human Impact

History of GIS Decade Milestones for computer-based GIS 1960’s Canada Geographic Information System (CGIS) developed: national land inventory pioneered many aspects of GIS Harvard Lab for Computer Graphics and Spatial Analysis: pioneered software for spatial data handling US Bureau of Census developed DIME data format ESRI founded 1970’s CGIS 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)

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

History of GIS

Major GIS-Only Journals International Journal of Geographical Information Systems Geographical Systems Transactions in GIS Geo Info Systems GIS World

ArcView Basics Project (the foundation. Contains the documents) Views Layouts Views Themes compile maps for printing display 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 attributes Tables contain the attribute data of a theme Scripts Charts

Introduction to GIS (1) Four basic steps for map production Data Collection Data Display / Explore Data Analysis Map Composition

. . Map Characteristics In addition to feature locations and their attributes, the other technical characteristics that define maps and their use includes: Map Scale Map Accuracy Map Extent and Data Base Extent

Fundamentals of GIS Mapping 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 provide descriptions of geographic phenomenon spatial and non spatial information map features like Point, Line, & Polygon

Map Features Map 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

Where GIS is being Applied l: Urban Planning, Management & Policy Zoning, subdivision planning Land acquisition Economic development Code enforcement Housing renovation programs Emergency response Crime analysis Tax assessment

Where GIS is being Applied: II Environmental Sciences Monitoring environmental risk Modeling storm water runoff Management of, floodplains, wetlands, forests. Environmental Impact Analysis Groundwater modeling and contamination tracking

Where GIS is being Applied: III Political Science Redistricting Analysis of election results Predictive modeling Civil Engineering/Utility Locating underground facilities Designing alignment for freeways, transit Coordination of infrastructure maintenance

Where GIS is being Applied: IV Business Demographic Analysis Market Penetration/ Share Analysis Site Selection Education Administration Attendance Area Maintenance Enrollment Projections School Bus Routing

Where GIS is being Applied: IV Real Estate Neighborhood land prices Traffic Impact Analysis

Summery Contributing Disciplines to GIS • Landscape Ecology • Geography • Cartography • Remote Sensing • Photogrammetry • Surveying • Geodesy • Statistics • Operations Research • Computer Science • Mathematics • Civil Engineering

Summery GIS As A Set Of Interrelated Subsystems: 1. Spatial and Attribute Data Base 2. Cartographic Display System 3. Map Digitizing System 4. Database Management System 5. Geographic Analysis System 6. Image Processing System 7. Statistical Analysis System 8. Decision Support System