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GIS, Geographic Information System, is a computer-based tool for mapping
and analyzing things that exist and events that happen on Earth. Examples
are natural disasters, overpopulation, pollution, war, and all other
major challenges in the world today all that have a critical
geographic dimension. With GIS, we can perform better and faster tasks
of creating maps, integrating information, visualizing scenarios, solving
complicated problems, presenting powerful ideas, and developing effective
solutions. Today, GIS is widely used by individuals, private and public
organizations, schools, governments, and businesses. For instance, GIS
is used by enterprise to locate new businesses sites, explain events,
predict outcomes, and plan strategies. In GIS technology, common database
operations such as query and statistical analysis are integrated with
the unique visualization and geographic analysis benefits offered by
maps.
GIS stores information about the world as a collection
of thematic layers that can be linked together by geography.
Geographic
Reference of Geographic Information
- Explicit: Latitude, longitude, or national grid coordinate
- Implicit: Address, postal code, census tract name, forest
stand identifier, and/or road name
Geocoding is a process used to create an explicit geographic
reference (multiple locations) from implicit references (descriptions
such as addresses). This is used to locate features such as a
business, event, or a natural disaster (flood) for analysis.
Models
of Geographic Information (for Storing Data)
- Vector Model: Encodes and stores information about points
as a single x, y coordinate, lines (roads and rivers) as a collection
of point coordinates, and polygonal features (sales territories) as
a closed loop of coordinates. It is more useful to describe discrete
features than to describe continuously varying features (soil type
as opposed to accessibility costs for hospitals).
- Raster Model: Used to model continuous features. It consists
of a collection of grid cells (like a scanned map).
Components
of GIS
GIS integrates the following components: hardware, software, data,
human resources, and methods.
- Hardware
- Computer on which GIS operates. Includes monitor, input devices,
and printer.
- Software
- Provides functions and tools needed to store, analyze, and display
geographic information.
Example: ArcView 3.1 and ARC/INFO 7.2.1. Key software components:
Tools for the input and manipulation of geographic information, a
database management system (DBMS), and tools that support geographic
queries, analysis, and visualization.
- Data
- The most important component. Geographic data and related tabular
data can be collected in-house or purchased from a commercial data
provider. GIS will integrate spatial data with other data resources
and can even use a DBMS used by most organizations to organize
and maintain their data to manage spatial data.
- Human Resources
- GIS technology is of limited value without the people who manage
the system and develop plans for applying it to real-world problems.
GIS users range from technical specialists who design and maintain
the system to those who use it to help them perform their everyday
work.
- Methods
- A successful GIS operates according to a well-designed plan and
business rules, which are the models and operating practices unique
to each organization.
Five
Processes Performed by GIS
- Input
- Data has to be converted from paper maps into digital format in
a process called digitizing. This can be done either manually or with
a scanning technology. Some data is available in digital format and
can be obtained from data suppliers.
- Manipulation
- Data must be transformed to the same scale (degree of detail or
accuracy) before integrating it.
- Management
- Large collections of data are stored, organized, and managed in
a database management system (DBMS). GIS uses relational design, in
which data is stored as a collection of tables. Common fields link
these tables.
- Query and Analysis
- Query questions like "How far is it between two places?" "Where
is land zoned for industrial use?" Analytical questions like "If
I build a new highway here, how will traffic be affected?" "Where
are all the sites suitable for building new houses?" GIS uses
buffering to determine the proximity relationship between features.
Example: What is the total number of customers within 20 kilometers
of this store? An overlay, or spatial join, can integrate data on
soils, slope, and land ownership with tax assessment. Different data
layers are integrated together.
- Visualization
- Maps are very efficient at storing and communicating geographic
information. In GIS, the results and map are integrated with three-dimensional
views, reports, photographic images, and other output (multimedia).
Advantage
of Using GIS
- GIS allows the user to bring all types of data together based on
the geographic and locational component of data
- GIS maps display many layers of useful information
- Visualizes scenarios and manages data
- Relationships between data become more apparent and data becomes
more valuable
- Reduced costs to businesses
- Aids in decision-making (location of new housing: low-risk area
or close to population center)
- Presents powerful ideas
Global
Positioning System (GPS)
The Global Positioning System uses satellites and computers to compute
positions anywhere on earth. It is a system of satellites that allow
a user with a receiver to decode time signals and convert the signals
from several satellites to a position on the Earth's surface For this
project, GPS was used to connect an inventory of housing conditions
with a GIS map. GPS data will be gathered directly from locations (cities
in Kosovo). A person will go around a house and GPS will help them to
know where the house is located. The information will be used in GIS
Kosovo map. Separate data with information on the inventory of housing
conditions will be collected and stored in a database. This is not a
major goal of the project however.
Layers/Themes
of a GIS Kosovo Map
The following are layers/themes that might be considered to create
the map:
- Cities: Gives us information about cities in Kosovo and cities
of neighboring countries.
- Political Boundaries: To see where each city in Kosovo is
separated either with another country or city. This layer will also
give us information on how large or small a city is.
- Population: Provides information on the most or least populated
cities of Kosovo.
- Total Number of War Crimes Plotted Across a Region: Provides
information on the region in which crimes were committed as well as
which regions have high crimes totals.
- Military Units: Provide information where military bases
were located.
- Mass grave sites: Where people were buried. A massacre might
have been committed at that region.
- Events Plotted Through Time: Provides information on what
types of crimes or events occurred through time
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