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Preface Geographic Information System is the new area with diversified applications in Civil Engineering, Geosciences, Forestry, Disaster mitigation, Environment and Ecology, Infrastructure planning, Utility mapping, Business, Mobile mapping, Information Technology and in many more fields. Since nearly 80% of the real world data are spatial in nature, GIS technology has been popularized overwhelmingly. It is not overestimation that GIS will be used in day to day life within next decade. Already developed countries use GIS widely and it will be used in day to day activities in developing countries also in near future. Reduced cost in hardware and software in GIS made it possible to reach most of the government organizations, research institutions, academic institutions and non governmental organizations. Although lot of data are available in paper format, if they are not collected, stored in a structured way for visualizing the real world, then the data do not serve any purpose. But this bottleneck has been eliminated by using GIS. Mobile mapping is the new area in which dynamic GIS maps are used in cell phones to find the actual location of a person. Anyone shall find a persons exact location when the cell phone is integrated with GPS and GIS maps. This will become reality in all parts of world in this decade. It is important to use any tool with its background knowledge. Also GIS is a tool and it has been used as an attractive tool nowadays. It is very much important to know the basics of GIS and their applications. Hence to explain the concepts of GIS in a simple language, this book has been attempted. Thus the book covers basics of data types, database concepts, map projections, errors and removal of errors, advanced analysis, web GIS, implementing a GIS project, various software and hardware requirement and advanced GIS applications. Hence any user in GIS will find this book as a catalyst to understand GIS. Also a GIS resource bank is provided which will give the users more information. Glossary consists of definition of important GIS terminology. It is advisable to read the glossary before actually going through the book, hence the readers will understand the GIS easily. The aim of this book is to provide a textbook on GIS in a simple style for the beginners in diversified disciplines. This book shall be used as a text book for undergraduate, post graduate students, GIS users and researchers.

1.1 INTRODUCTION Geographic Information System (GIS) is the new emerging field and grows at very rapid pace. Now GIS is a billion dollar industry with applications in varied disciplines. At present, GIS is being used by professionals from various disciplines. In this decade, GIS is being used by experts who are good in GIS technology for various applications. The development trend indicates that GIS will be used by common man in near future and at the same time, advanced GIS analysis will be carried out by GIS experts. Any technology is developed out of necessity and GIS is of no exception. When a large amount of data were available for water distribution systems, road network, sewer lines, telecom lines, electricity lines, gas pipe lines, state wise population, natural resources etc, it is important to store, maintain and retrieve the data for applications. It is not possible to manually browse through the large amount of paper records. Also even if the data is available in an unorganized way in the computerized environment, it is not useful. Hence if the data are referred to locations in earth surface and the data are stored in an organized way, it is possible to retrieve and analyse the data for applications. Hence the solution is GIS and developed today into reality. Developed countries are using GIS widely in many areas but developing countries are moving towards the development of GIS database for their resources. Remote sensing, aerial photography, cartography, surveying and other field instruments for attribute data collection contributes to the data acquisition. Cartography, surveying, geography, geodesy contributes for mapping process. Disciplines like computer science and statistics, mathematics involved in processing and analysing data . Computer science and mathematics involved in storing the data structure. GIS maps are intelligent. It has many advantages compared with paper map in this digital age. Spatial data means data which are referenced to earth. Maps, satellite imageries, aerial photographs are example of spatial data. Attribute data which are attached to spatial data are called as aspatial data or non-spatial data. If these data are brought into GIS then it is stored in a standard format, it is possible to update, share, retrieve, manipulate and analyse quickly. Much of the time and money is saved in case of reproduction and better decisions could be made

2.1 INTRODUCTION GIS is a tool that can be used in varied disciplines ranging from civil engineering to business. Remote sensing data is often brought into GIS to have a complete data set in many natural resource application areas. Full capability of GIS is not used widely. Many a times people use GIS only for digitising maps and to do simple query on maps. But it can also be used in modeling, simulation and forecasting, only then one may regard GIS technology is utilised to its full potential. Some GIS softwares handle simple problems for location based services while other complex softwares posses advanced modules to do all types of spatial, network and 3D analysis. Integration of softwares used in natural resources study are being interfaced with GIS to create scenarios. Remote sensing and GIS technology is useful in the following fields:

3.1 INTRODUCTION Geographic Information System handles large volumes of data. It is important to know the nature of data, instruments from which the data is collected and represented in computers. GIS data is either spatial or aspatial. Data is an important component in GIS. Digital data are available for some projects. but for many projects, input data may not be available. Now-a-days, data is supplied by many government, private organizations and also available on internet. If data for a particular project is not available, then the user has to collect the data from satellite imageries, GPS and other instruments and maps from various sources. Spatial Data All locations in the earth surface are spatial data. Location of a city, location of a river, location of a lake are represented in earth by their latitude or longitude in global coordinate system or as x,y coordinate in Cartesian coordinate system. Spatial data consists of location, shape and size in earth. A village boundary is represented as a polygon in map. The village is having certain shape of irregular polygon with definite area. As all these are mappable , they are called as spatial data. But name of the village, revenue of a village and description about a village and called as non-spatial or aspatial data.

4.1 INTRODUCTION Database management system is a computer program to store, search, manipulate retrieve and give the result. Vast amount of spatial data are available and it is necessary to arrange them, store them for retrieval and analysis. Attribute data adds intelligent to GIS. Without database, a GIS will be just a Cad software. Cad softwares do not have database. GIS softwares have their own databases besides it has the potential to link with external database like Oracle, MS Access, MS Excel, Informix, INGRESS, Sybase and dbase. The data available in paper has to be digitally stored in a proper order. Previously the data were stored in a a flat file format where the data was stored without any structure. But to search and retrieve and analyse the database, database structures were developed. There are of 4 types of database structures namely Hierarchical, Network, Relational database and Object orientation. Tables are made of rows and columns. Rows represent a map feature. Columns represents characteristic of map feature. Row is called a record or a tupule column is a field or an item. Table 4.1 is a table where rows 1, 2 and 3 represent the locations with the soil types. A column soil type represents various soil types.

5.1 INTRODUCTION A GIS database without single error is reliable for decision making. There are various possible sources of errors in GIS. If an error is not removed during scanning, the final output will also have that error. Besides whatever the work has been carried on wrongly scanned map it will add to errors because the source map itself's erroneous. This is like garbage in garbage out proverb. If wrong data is taken for analysis it will only result in wrong output. Hence it is important to remove error at every stage of GIS work. It is important to locate the sources of errors so that due care may be taken while handling a project. 5.2 ORIGINAL SOURCES OF ERRORS All the equipments which give attributed data and spatial data will give errors. Before going to field or before collecting data all the related instruments should be calibrated properly. Also the instrument should not cross the permissible error. Besides these while using data from diversified sources errors pertaining to those instruments are mixed to give a different result. When very good accuracy is desired data should be collected from high end equipments. Even if one adds the data from a comparbly less accurate instrument to the data of many accurate instrument is then the result obtained finally will not reliable enough. Global Positioning System (GPS) is available with mm accuracy to meters accuracy. Also surveying with suitable map projection and datum is important; otherwise the result will be wrong. Survey instruments posses some inaccuracy and when a person is using it he should have the accuracy over the instrumental like rain gauge, water level recorders which give attributed data which should be checked for instrumental inaccuracies and method of data collection before using it. Likewise satellite and aerial sensors miss some data and some error are inherent. Such errors should be removed before moving ahead. Errors are resulted due to map reduction, enlargement, data editing and computation method adopted. At the same mapping instruments also possess inaccuracies. When after certain interval a person is going for survey, the registered object may have been changed. Many new features might have come up. Hence the established control points are changed and if the wrongly placed control points are taken for survey then the result itself will be wrong. If proper resolution is not available in the instruments, then the instruments may not capture the minute details which are required.

6.1 INTRODUCTION Besides simple analysis, GIS is useful to do advanced analysis like network analysis, spatial analysis, 3D analysis and modeling. Different softwares are available to perform such analysis and the above mentioned analysis is done in separate modules of the softwares. 6.2 NETWORK ANALYSIS Network consists of well connected linear features. Roads, railway line, water distribution system, sewer line, streams are some of the examples of networks. These networks consists of nodes and arcs with designated directions and connection with other linear features. Networks are topology based with attributes for the flow of objects like traffic. Road network will be considered for explaining network analysis. Road map is digitised with nodes and arcs. Signals, accidents are represented as points. Road is represented as line and two or more roads intersect at nodes. Attributes are added to the nodes and lines. Dynamic segmentation model is used for network analysis. It is built on lines of network. In road network analysis, attributes for travel time, one way street, two way street, right turn, impedance are added to the nodes and arcs. A link is the line running between two nodes. Link impedance is the cost of passing through the link. Travel time is different in links in cities due to varying traffic at different locations. Time taken to pass through a known length of link may give the cost but the travel time in a link is not uniform because of varying speed designated in the link as 20 km per hour and 30 km per hour. Hence it is important to consider the length of link and also the travel time. If the speed limit is 20 miles per hour for a length of 2 miles, then the travel time is 6 minutes (2/20x60 minutes). Also tuning in the network is considered. A road may have a maximum of 12 possible turns excluding U turns. There are right turn, left turn, straight way for each road. Also U turn is possible. This turning takes different time depending on the signal. Straight way takes less time but left and right turn may require some more time. If signals is available then signal time should also be taken into account. Fig 6.1 show the possible turns in a road.

7.1 INTRODUCTION Web technology revolutionised information technology and GIS of no exception. Analysis of maps available in internet through remote personal computer is called as web GIS. The term web is GIS synonymous with the term internet GIS. Most of the software vendors in the field of GIS have developed their GIS compatible to internet. The advantage of internet GIS is no need to own a GIS software in the personal computer. Maps available in a web site can be analysed for GIS functions as one could do with GIS in standalone personal computer. Applications of web GIS is not limited. Most of the governmental agencies, business people and others put their data in their server and the data could be analysed spatially for the users requirement. Internet mapping is simple, cost effective and reach vast audience. Internet GIS is useful in field like civil engineering, government organisations, forestry, environment, goescience, utility planning etc.

8.1 INTRODUCTION To implement a good GIS project, a well structured project design and management are essential. Well planned project will give fruitful result within the stipulated time. Project not completed in time will not incur more cost and also the time delay will add negative value to the project. Hence all the elements in project planning and implementation should be considered to have a desired result. Some of the issues are also present in GIS and they will be rectified in the next decade. 8.2 PROBLEM IDENTIFICATION Any project is coming into reality due to necessity. If water scarcity is more in a hard rock region with sufficient rainfall, it is important to augment groundwater resource using rain water harvesting structures. It is important to build water harvesting structures like check dam, percolation pond in suitable locations so that groundwater recharge will be more. Hence a problem is identified and the project work may be carried out by a government or private organisation and the result is given to the government to implement the project. Likewise many area may require a project in GIS environment for planning. Once a project is created any development taking place can be added and GIS database is updated.

Glossary Absolute location: Points represented in terms of a standard coordinate systems like latitudes and longitudes. Accuracy: Deviation between the measured value and the true value. Active X Control: Creation of compound documents consisting of multiple source of information from different applications. Address matching: A mechanism for relating two files using address as the related item. Geographic coordinates and attributes can be transferred from one address to another. For e.g. a data file containing students address can be matched to a street coverage that contains addresses creating a point coverage of where the students live. Adjacency: A spatial relationship that can be used to select features that share common boundaries. Affine transformation: Linear transformation (rotation and scaling) and translation (shift of position) used to register maps. Allocation: A study of spatial distribution of resources through a network. AM/FM: Automated Mapping and Facility Management (Software for the management of utilities like water, power, telecom lines, wastewater, gas pipelines etc.) Annotation: Text used inside the maps to identify the features. Arc: A line consisting of a series of vertices joined by straight sections. ArcInfo Grid: Raster format of ESRI ArcInfo software. Arithmetic operators: Operators used for multiplication, addition, subtraction of maps. Artificial Intelligence: A branch of computer science where softwares are used to make the computers think and work. Expert systems are built with artificial intelligence. Aspect: The directional measure of a slope. Attribute data: Data that describes characteristics of spatial data.