An Introduction to Geographic Information Systems Dr. Nitin Kumar Tripathi Remote Sensing and GIS FoS School of Engineering and Technology AIT Bangkok, Thailand [email protected] 1
GIS Geographic Information Systems 1. It is an information system that is designed to work with data referenced by spatial or geographic co-ordinates 2. A database system with specific capabilities for spatially-referenced data, as well as a set of operations for working with the data 2
Why we need map? Why we need GIS? Why we need Information System? Why we need Information? From where information comes? Decision 3
Picture equals 1000 words Picture need no language 4
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Landsat TM, FCC541, RANONG 8
Geographic Information System overview USER NEEDS USER ACTION OUTPUT PRODUCTS PLANNING DATA MANIPULATION & STORAGE ANALYSIS DATA COLLECTION 9
Cartography GIS : The result of parallel CAD development in many data processing techniques Surveying GIS Photogrammetry Spatial Analysis using rasterized data from thematic map Interpolation from point data Remote Sensing Techniques Global Positioning Systems TIME Technical & Conceptual Development Dr. Nitin Tripathi,AIT
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5 7 20 20 23 Raster Data 3 4 5 23 19 5 5 5 24 20 14.5 16.9 22.5 22.6 23.3 8 1 23 24 25 14 15 15 24.9 20.9 7 7 21 25 25 14 10 10 26.4 21.6 9.5 9.9 2.5 2.6 2.3 11 11 10 1.9 1.9 17 9 24.6 26.7 27.8 9 5 5 2.4 1.6 9 8 1.6 2.7 2.8 12 14 22.6 26 26.5 5 7 1.6 1.0 1.5 + 12
5 7 20 20 23 Raster Data 3 4 5 23 19 (-) 5 5 5 24 20 8 1 23 24 25 7 7 21 25 25 9.5 9.9 2.5 2.6 2.3 11 11 10 1.9 1.9 9 5 5 2.4 1.6 9 8 1.6 2.7 2.8 5 7 1.6 1.0 1.5 13
Do we need GIS? Reasons to have a GIS: - geospatial data are poorly maintained - maps and statistics are out of date - data and information are inaccurate - there is no data retrieval service - there is no data sharing - Data from many sources can not be integrated - Data and maps can be accessed online - Many kind of decision making possible by adopting multi-criteria approach. 14
Benefits from a GIS : - geospatial data are better maintained in a standard format - revision and updating are easier - geospatial data and information are easier to search, analyze and represent - more value added product - geospatial data can be shared and exchanged freely - productivity of the staff is improved and more efficient - time and money are saved - better decisions can be made 15
Survey and Mapping
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Nutrition & Malnutrition “Nutrition -intake, absorption and utilization of food to fulfill our body’s dietary needs. ‘Mal’ to ‘Nutrition’ - the unbalance between foods taken by our body and the foods needed by our body”. Types of Malnutrition Defined by The World Health Organization (WHO) 1. Under-nutrition (food intake > body requirement) 2. Over-nutrition(food intake < body requirement) 29 www.pingofhealth.com
MULTIPLE BURDEN OF MALNUTRITION Co –existence of two or more forms of malnutrition
Determining the Livability of a City 31
Questionnaire 32
Data collection Photos 33
34 Population Density map
Livable zone using AHP 35 LC classes LC levels High 38.45 – 46.12 Moderate 33.62 – 38.45 Low 28.56 – 33.62
Basic Information from a GIS What is at......? (Locational question ; what exists at a particular location) Where is it.....? (Conditional question ; which locations satisfy certain conditions) How has it changed........? (Trendy question ; identifies geographic occurrence or trends that have changed or in the process of changing) 36
Other Terms Used for Geographic Information Systems • Multipurpose Geographic Data • Resource Information System System • Natural Resource Management • Multipurpose Land Use System Information System • Computerized GIS • Spatial Data Handling System • System for Handling Natural • Geographically Referenced Resources Inventory Data Information System • Image Based Information • Geo-Information System System • Spatial Information System • Land Resources Information System • Environment Information System • AGIS - Automated GIS • Spatial Data Management & Comprehensive Analysis • Multipurpose Cadastre System • Land Information System (LIS) • Planning Information System • AM/FM - Automated Mapping and Facilities Management 37
Major Applications of GIS Street Network-Based • address matching • vehicle routing and scheduling • location analysis, site selection • development of evacuation plans 38
Major Applications of GIS Facilities Management • locating underground pipes, cables • balancing loads in electrical networks • planning facility maintenance • tracking energy use 39
Major Areas of Applications of GIS Land Parcel-Based • zoning, subdivision plan review • land acquisition • environmental impact statements • water quality management • ownership of maintenance 40
Major Applications of GIS Environment and Natural Resource • forest management • wildlife habitat, migration routes management • wild and scenic rivers preservation • recreation resources planning • floodplain management • wetland preservation • agricultural lands management • groundwater modeling and contamination tracking • environmental impact analysis • viewshed analysis 41
Spatial Operations ASPATIAL QUERIES SPATIAL QUERIES Queries that in being Queries that can only be answered do not use the answered using the stored X & Y stored X & Y location of the location of the feature and its feature, nor does it describe relationship to other features on where the places are in the earth's surface. Spatial relation to each other. queries can not be answered without geography and topology. Example: • How many people are Examples: working with GIS in • How many people are working with Thailand? GIS in the major population centers in Thailand? 42 •Which centers are within 50 Km of each other? •What is the shortest route that passes through all of these centers?
COMPONENTS OF A GIS INPUT QUERY GEOGRAPHIC DATABASE INPUT Position Topology Attribute MANAGEMENT SYSTEM RETRIEVAL TRANSFORMATION 43
DISPLAY & REPORTING VISUAL PRINTER PLOTTER MAGNETIC DISPLAY MEDIA TERMINAL MAPS TABLES FIGURES PRESENTATION 44
Geographical Concepts • Spatial Objects - geographic area with associated attributes and characteristics • Point - a spatial object with no area – key attributes : geodetic location other data based on application • Line - spatial object made of connected sequence of points – no width – spatial location on either side of the line • Nodes - intersection of line or end of line segment 45
• Polygon – A Closed Area – simple polygon undivided area – complex polygon divided area of different characteristics • Chains – special kind of line segment which corresponds to a position of the boundary edge of a polygon • Scale – ratios of distances represented on a map to their true length on the earth’s surface – dimensionless – small scale map – large scale map
• Resolution : distinguishing individual parts – Spatial resolution for geographic data as the content of the geometric domain divided by the number of observations, normalized by spatial dimension • Spatial Domain – Area covered by the observation More information => mean resolution gets smaller Less information => mean resolution gets larger 47
Components of GIS Computer Hardware & Software Organizational Database Structure & People 48
Geographic Features Geographic features are represented by two types of data. SPATIAL DATA Street Name Address range on left Address range on right Length to travel Directions to travel ATTRIBUTE DATA 49
The Geographic Database Spatial and attribute data types are Geographic Database linked together by a common identifier. 50
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