GIS design and technology - Essay Example

? GIS DESIGN AND TECHNOLOGY (College) (Year) Number Geographical Information System was developed to be a technological tool which can be used to understand the geography of the world and make decisions which are both logical and intelligent. It was created with the ability to assemble, analyze, manipulate, update, store and display information which has been geographically referenced according to the location of the data (Elangovan, K, 2006, p.3). It is a computer system with many components which include software, hardware like scanners, digitizers, CD, floppy, the internet and intranet and keyboards, data, people institutions and organizations which are arranged to analyze the stored data on areas in the earth and display the decisions. For it to function it requires a vast amount of data hence making the projects which use GIS very expensive. Its data originate from images of satellites, maps, GPS data from survey an all other instruments which can attribute data. Before the development of Internet GIS large amount of data of different field like road networks, sewer lines, telecommunication lines and natural resources were useless as they were available in large unorganized states which makes them hard to retrieve and analyze. The creation of GIS solved this problem hence the organization of GIS databases which had all the information needed. Elangovan (2006, pp. 5&6) attributes GIS development is to different disciplines like databases, computer science, computer mapping, Computer Aided Design, remote sensing, geography, Cartography and many more. Different discipline had different functions in the GIS. Databases is used to store, manipulate and retrieval of the data. Computer mapping is used to create maps in the computer while the remote sensing is used to take satellite images. Through the combination of these and other disciplines the GIS emerged a super field which is very helpful. The development of GIS can be generally grouped into four stages of development according to Elangovan (2006, p.10). Between 1960 and 1975 there was introduction of the GIS concept. Due to this fact only few people used in mainframe computers. In between 1973 and early 1980s though many experiment and practice were done, there was little information as individuals were the one doing the research hence duplication of work. There was development of many GIS software between 1982 and late 1990s. This improved the growth of GIS. The last stage is between 1990 and 2000. In this stage there was standardization of the GIS due to the easy availability of software both for ensuring user friendliness and for a platform for working. After 2000 GIS had multi use like virtual reality, mobile mapping and web based GIS. Massachusetts Institute of Technology in 1965 was successful in the creation of processing of graphic data through computer aid. This fastened the development of GIS. Agencies in USA, Canada and the UK started using the GIS for the processing of large data amounts. The first to use GIS was the Canada government. The Canadian government used the GIS for management of land and other resources. The US government used the GIS for Geographical Retrieval and Analysis System (GIRAS) which is used to analyze data on the use of land and land cover. In 1970s the Swedish bank on land data used the GIS to make the registration of land and properties automatic. After the development of Geographical Information Mapping and Management System (GIMMS) by the University of Minnesota, in 1963, there was publishing of the Atlas of Britain through the use of information in the GIS. It was printed by the Bickmore and his team of cartography. In 1970 there was publishing of the first multicolour map in Britain. The production of commercial GIS was done by the Harvard Graphic labs in 1970. There was also creation of many cartographic packages like GIMMS, GRID, GEOMAP and MAP. Between 1970s and 1980s there was development of many GIS packages. In 1975 after the first academic meeting about GIS in the UK there was release of the first text on GIS. At last in 1980, GIS and cartography merged leading to computers with super speed. By 1986 Intel 80386 processor had been developed for the microcomputer. In the 1990s the Raster data structure and the Quadtree data structure were developed. From 2000 to the present there have been multiple multimedia tools and virtual realities which have been developed (Elangovan, 2006, pp 5&6). Number 2 The traditional GIS desktop over years has been advanced leading to the emergence of a new technology called the Internet GIS. This is technologies which can access, manipulate and display information from the internet. It has led to the coverage of a wider coverage to the audience. Due to this it has been greatly accepted by agencies of the government, institutions of education and producers and users of geospatial. Peng and Tsou (2003, p. 5) believe that information technology has been the main booster to the development of the GIS.. The mainframe GIS are programs which were used on a mainframe with access to the terminal. The desktop GIS is one computer which stands alone and does not exchange information with other computers or network programs. The distributed GIS works on the recent development of Internet and wireless data technology. The development of the mainframe GIS used the model of monolithic for computing. All the programs which were used in the computer were in the mainframe. Access to the data and the function necessitated access to the mainframe server through dump terminals over LANs. The functioning of the GIS in the desktop is determined by the programs which are found in the desktop of the computer. The desktop GIS are categorized into two: the stand-alone desktops and the LAN-interface desktop. The stand alone is a desktop in which it contains all GIS functions. The LAN-user adopts the model of two tier client/server. The limiting factor is the fact that to have the ability to use the computer you must have the ability of accessing the programs. (Peng & Tsou, 2003, p. 6). Through the integration of GIS and the technology of the internet users have the ability to access information easily without the use of specific GIS software. The internet is based on Client/server technology. The client requests for a specific service while the server receives the requests, processes it and return the information back to the client. It uses a set of communication protocols like TCP/IP, FTP, HTTP and others. Through the internet, the users have ability to update their software and access specific information they need. You can either deploy a GIS through the server-side application approach or the client-side application approach. To have an advantage in deployment, development and maintenance of the data you take the server side application. This is because it complies with all the standards of the internet. The disadvantage of the server – side is the limited interface for the users and the performance being poor. The client-side application also as advantages in some sectors like it has the ability to enhance the user interface; the performance can also be improved and solutions can be implemented through the use of vector data. The client-side is associated with disadvantages like the inability to distribute software and data. Through the use of communication protocols like the TCP/IP the connection between the server and the client is made. There are two types of client, thin and thick. The type of client is determined by the amount of processes which are being performed in the client-side. If the main function of the client is to request input and them produce output then it is a thin client. In a thin client most processing occurs in the servers-side. A client is thick when most processing is done on the client-side. Client/Server Model The client/server architecture has four main components: the client which serves as the interface for the user to communicate with the programs of internet GIS, the web server which receives the request of the clients, serves the web pages which are static, and invokes servers application, the application server whose function is to manage the transactions of the server, security and the balance load, and the map server. The map server processes the requests of the clients and generates results (Peng & Tsou, 2003, p. 20). Number 3 Internet GIS has many application. One such application includes the Java applet. The code or the applet, as a binary instruction, is usually transferred to the web browser. This ensures that the GIS application is provided for a GUI. The data which is vector-based is them transferred to the client. The data enables the complex function in the client GIS function. Java applets are programs which are small in size and are used together with WebPages. Each applet has a compact code. The code is usually downloaded together with the text on the page. When the applet reaches the server, there is execution of the code by the browser to the local machine. Due to this they have the ability of performing many different tasks that are otherwise impossible without the applet. Some of these tasks include displaying graphics which are found dynamically in the web pages, it gives the user the ability of clear interaction with the applet and hence be able to get new or more information from any database in the desktop. This makes the GIS a necessary commodity in any internet. Network Host machine Client machine Servlets-Applet communication The java servlets are loaded dynamically inside the JMV and service request from the server. The servlets run on the server’s side. This makes them not depend on the compatibility of the browser. Number 4 Due to this it has the ability of being used in many applications which are web-related. The other advantage of the servlets is their ability to handle many requests concurrently, forward a request to a different server and servlets and synchronize the requests. Through HTTP servlets has the ability to communicate to a user through an applet which is embedded in any HTML page. The development of GIS has led to many important developments. One of them is online mapping. They give the user the ability to move from one place to another with ease and create their own personal customized maps. In 1995, there was development of the GRASSLink. It is a web interface which has the ability of viewing any GRASS dataset, pan and zoom and click on the map with the information and get it. The TIGER map server was then developed. It has the ability to toggle on many geographical entities in the datasets. During the third generation of web mapping there was introduction of mashup. This was the art of combining data, mixing them up and offering the user and the web an application which is new. Through the use of an application programming interface (API), they have the ability to communicate between technologies with any need to modify the source code. The mapping mashup mostly interoperate through services of online mapping such as in Yahoo and Google. Mashup give the user the ability to import text, photos, links for the web and many more information and hence help you create your own personal map for your journey. Due to this, on the web pages you can come across many types of maps. Due to the dynamic nature of the web maps, they are very important. They can be changed, modified, removed or even add information that suites you. According to Jan-Menno Kraak who was a Dutch cartographer maps can be classified depending on their unique features. He classified maps into 9 types of web maps. The static web map is a map which is just like the paper map. The user has the ability of zooming in and out even though the content of the map is static. Due to it being static, the scale cannot be changed. The user also has no ability of viewing the edge of the map or toggle on and off. The main application of this map is in digital scanning of a paper map from a GIS package. The other type of map that can be found in the web is the dynamically created web maps. These are maps that can be dynamically generated on loading of a web page which is associated with the map. This type of data is appropriate for data which is constantly changing. The source of data which is used in the compilation of a Distributed web map is usually distributed. The special feature about this data is the fact that some of the data used in compiling of this map is from a different server through the use of special data sharing protocols which include WMS (Web Map Service), the WFS (Web Features Service) or the WCS (Web Coverage Service). The data can also be gotten from other website that was not necessarily for mapping purposes. Animated maps are used for data taken at different times. Due to this, the map has snapshots of the different times. They are mostly used in weather maps. The other common effect of using an animated map is to change the point of view of the user through the use of panning and zooming. This creates a flythrough of a place.The collection of data for the real-time web maps is different from the other types of maps. Through the use of sensors, they collect data. The sensors are usually along roads in urban centres so as to collect information about traffic. Another example of the real-time web map is the weather map. Personalized maps are maps which the user has an ability to add input to the map. The input includes the colour scheme, the method of classification, the title of the map, legend, the scale bar and all other elements which can be changed. These maps are mostly found when the user is trying to construct a map package through the use of GIS. Interactive maps are the most common maps in the web. They are maps which allow the use to interact with them through the use of zooming and panning. Through this they have the ability of changing the maps up-to a certain extent. Analytic web map is the use of a map in analytic functions like route finding. The users’ duty is to give the starting address and the ending address and the server for the map will analyze the information and give you the best route. Analysis is the other function of the GIS package. Collaborative web maps are maps in which a number of distributed people create the map and maintain it. A user can log in into a website and add input to a map. The classification of these maps is not perfect. Some maps are complicated and fall into more than one classification. As technology grows so has the use of web mapping. In the past, mapping was only done by large companies and institutions of the government. This days with the evolutions of portable computers and other electronics like the I-pod, cell phones, PDAs and portable GPS devices, there is easiness in web mapping hence the users have the ability to pinpoint the main area they are interested in. Number 5 GIS has two widely used data structure; the vector and the raster format according to Korte. B & Korte. G (2001, pp 81-83). Depending on this formats we have two models the vector model and the raster format. They are used in a fully functioning GIS. The vector model is used to represent maps in CADD, AM/FM and GIS. In this model, the information about the lines, points and the polygons are encoded and then stored in a collection of x, y coordinates. The location of a point feature in a map is described in terms of x, y coordinates. If the feature is linear like a road or river, the coordinates are given as a point. Polygonal features which include territories of sae and lakes are stored using closed loops of coordinates. It is most appropriate in the describing of a discrete feature example a building but not continuous features like the land cover. Files in raster model are arranged in rows of uniform cells which are coded depending on the value of the data. The manipulation of a data file is faster through a computer due to the fact that it has less information compared to the vector data. It approximates the boundary line and depending on the approximation they relate the size of the cell. It is most common for both types of data to be used at the same time. On a vector display, raster data is used to show the background of the shown area. Sometime there is also conversion of one type of data to another. Vectorization is the process of converting raster data to vector data. Geo-web is a network distribution of interconnected GIS data on geography which can be globally accessed and integrated through the use of the GML Data representation. Through it users can access geographical information which is current and accurate from many sources around the world. GML is an XML based language mark-up. It is used to do the encoding of the different type of GIS data from real-world objects. Data collection for the GIS task is both time consuming and expensive. The two main method of data collection is data capture and data transfer. Data capture can be used for both primary, measuring directly, and secondary, deriving the information from other sources, for both raster and vector types of data. Data transfer is the importation of digital data from different sources. The data that is collected is then stored in databases which are operated and managed carefully because they are the backbone of analysis and the activity of decision making. The creation of a database management system (DBMS) allowed the multi-user access of a specific set of data. This necessitated the improvement of security and transaction access (Longley, Goodchild, Maguire & Rhind, 2010 p.229). Data is analysed through the use three functions: attribute data queries, spatial queries and set queries. This analysis can be carried out in all type of spatial da including points, areas, lines, nodes, edges and faces. The result of analysis is called a query set. It is a group or elements of features that meet a certain criterion. Reference Anon, Types of Maps. (Online) Available at https://www.e-education.psu.edu/geog863/book/export/html/1914 [Accessed 9 January 2012]. Elangovan, K., 2006. GIS: Fundermentals, applications and implementations. New Delhi: New India Publishing. Korte, B. G. & Korte, G,. 200. The GIS Book. Albany: Centage Learning. Longley, P. A., Goodchild, M.F., Maguire, D. J., & Rhind, D.W., 2010. Geographical Information System and Science. Chichister Wiley: John Wiley and Sons. Peng, Z., & Tsou, M., 2003. Internet GIS: distributed geographical information services for the internet and wireless network. Hoboken: John Wiley and Sons. Read More