Glimpse of GIS (1)

Before the 1940s, geographical analysis was done by overlapping (overlay) several types of maps in certain areas. But since the 1950's developed a digital system to perform the analysis in solving spatial problems. Until now, the various roles of Geographic Information Systems have been developed that can be used to address various aspects of the problems related to space.
Developments in the field of computer technology has brought enormous benefits for the dissemination of information. With the internet, for example, we can see the beautiful places in all corners of the world when it looks utilizing geographic information systems. Geograft information system (GIS) are happier than the information system applied to geographic data or data base tools for analysis and mapping, and there is something that happens on earth. GIS is becoming known in the 1950s.
In the first studies in the field of GIS among the researchers limited the field of Botany, Meteorology and transportation. They started making maps yanng automatic and tried to present cartografl computing.
Geographic Information System (Geographic Information Systems) is a computer based information system used to present and analyze digital geographic sightings and events that exist in the earth's surface. The presentation of the digital means to change things into digital form. Any object that is in the earth's surface is a "geo-referenced", which is the framework of the relationship to the GIS database. Database is a collection of information about something and its relationship to one another, while "georeferenced" indicates the location of an object in space is determined by the coordinate system.
All maps have the same boundaries with the location coordinates are the same on all maps. This is a way to analyze the thematic maps and the characteristics of space to gain a better knowledge in this area. SIG is currently one of rapidly evolving technology. This technology consists of software and hardware designed to organize data related to the earth to analyze, estimate and description of cartography. Information about the Earth's space is very complex, but the geographic data are generally contains 4 important aspects, namely (Zhou, 1998):
The locations related to space, the space objects that are characteristic of the coordinate system (projection of a map). Attributes, which describe information about the objects needed space.  Space relationships, logical or quantitative relationship between space objects. Time, the time for data acquisition, data attributes and space
Geographic analysis and mapping is not a new thing, but the SIG provides various facilities to help accomplish the tasks for a better, more efficient and more precise results. GIS is a system consisting of computers, software, data, human, organizational and institutional rules for the collection, storage, analyzer, and dissemination of information about places on earth (Dueker and Kjeme 1989) sutu SIG is working on the design of information systems for the had a data element space or geographic coordinates. GIS technology integrates database operations like data search and statistical analysis and geographic analysis are presented in map form. This unique capability makes GIS widely used for example to explain events, predict outcomes and strategic planning.
Simply SIG is:
    Computer-based tool for mapping and analysis of something that is there and the events that happen on earth.
    A set of tools for collecting, storing, repairing, modifying and displaying the data space is actually the earth's surface for a particular purpose.
    Computer-based system equipped with four spatial ability to handle data, namely:
~ Entering data (input data).
~ Save and fix the data (the data store and retrive).
* Manipulate and analysis (manipulation and analysis).
* Generate the data (data output).

Geospatial data can be distinguished on the entity and attribute. Entity is an object that can be distinguished from other objects based on attributes. Data to be obtained from the application of GIS, digitized and scanned maps, databases on a variety of formats (dBaseIV or text), GPS, remote sensing and aerial photography. Appearance of digital maps of spatial data has many advantages over conventional maps.
GIS has the ability to answer questions about, location, condition, trends, patterns, models, questions nonspasial and spatial questions.
 
    Location, What's on ... ?
The initial question is to find what lies at the particular location. Location can be a place name, postcode, and spatial references such as latitude and longitude coordinates x, y. For example, at one million points N and 550,000 E type of soil or land uses are there?
 
    Condition, Where is ...?
This question requires an answer spatial data. This question is to find a site with certain conditions, for example, where the forest land area of ​​20 ha at least that is open, the zone located 100 meters from the road and the land suitable for building, where is the location that has curh 2500 mm of rain per year?, Where is the field located, or where there is
Inceptisol soil type?
 
    Trends, since changes what ...?
This question involves two questions above to find the differences, such as changes in land use or the height at one time. An intriguing question in agriculture for example, how extensive land conversion to non-paddy fields, what percentage of conversions that happen?
 
    Pattern, pattern space ... what happened?
This question is the prediction of events in time or under certain conditions. For example, to determine whether landslides mostly occur near the river or to find out how much weirdness going on and where it is located, how far changes in the coast line of this dive five years, changes in land use and development of the area of ​​crop fields, is there any relationship between the type of soil in land productivity, relationship between the road surface to the level of accidents, flooding the area with the productivity and shading with plant growth.
 
    Model, If ... then ...?
This question is intended to determine what happened, for example, when new roads are added or if the spread of toxic substances into ground water, what happens when land use changes, when the air temperature increased by 50C?
The answer to this question contain elements of geographical and other information in accordance with the model.
 
    Non-spatial questions
GIS can also answer the question that is not referenced spatial, such as how the average number of unemployed in each county? The answer does not require spatial value, also does not explain where it is located.
 
    The question of spatial
Questions to answer the question of spatial both one-dimensional to three. For example, where the nearest road to the city center and where the city center. The answer to this question requires data of latitude and longitude and some other information such as distance. How large an area or how much volume to be supplied to a basin to be a flat surface.