GIS:

Geographic Information System (GIS) is defined as an information system that is used to input, 
store, retrieve, manipulate, analyze and output geographically referenced data or geospatial data, 
in order to support decision making for planning and management of land use, 
natural resources, environment, transportation, urban facilities, and other administrative records.

The sources of geospatial data are digitized maps, aerial photographs, satellite images, statistical 
tables and other related documents

GIS is a collection of methods to visualize,  manipulate, analyze, and display spatial data. GIS enables smart maps, 
these maps links databases to the maps. GIS is used lots of different areas suc as industry, government, education, 
business, environmental and emergency services. Simply put, a GIS combines layers of information about a place to 
give you a better understanding of that place. What layers of information you combine depends on your purpose—finding
 the best location for a new store, analyzing environmental damage, viewing similar crimes in a city to detect a 
pattern, and so on.



SPATIAL DATA:
Data that pertains to the space occupied by objects
Conceptually, points, lines, rectangles,surfaces, volumes and etc.

Physically, cities, rivers, roads, states,crop coverage, mountain ranges etc.

Applications include environmental monitoring, geographic information systems, earthquake research etc.


Geometric and varied Naturally high dimensional
Can be either discrete or continuous
May associate with non-spatial attributes


GEOSPATIAL DATA:
Geospatial data are spatial data associated with a location relative to the Earth.


GEOGRAPHIC FEATURE OR FEATURE:
A feature is an abstraction of a real world phenomenon. A geographic feature is a feature associated with a 
location relative to the Earth. A digital representation of the real world can be thought of as a set of features.



Historically, geographic information has been treated in terms of two fundamental types called vector data and raster data.

VECTOR DATA:
“Vector data” deals with discrete phenomena, each of which is conceived of as a feature. The spatial characteristics of 
a discrete real world phenomenon are represented by a set of one or more geometric primitives (points, curves, surfaces, 
or solids). Other characteristics of the phenomenon are recorded as feature attributes. Usually, a single feature is 
associated with a single set of attribute values.


RASTER DATA:
Raster data”, on the other hand, deals with real world phenomena that vary continuously over space. It contains a set of 
values, each associated with one of the elements in a regular array of points or cells. It is usually associated with a 
method for interpolating values at spatial positions between the points or within the cells. Since this data structure 
is not the only one that can be used to represent phenomena that vary continuously over space, OGC uses the term 
“coverage” to refer to any data representation that assigns values directly to spatial position. A coverage is a 
function from a spatiotemporal domain to an attribute domain. A coverage associates a position within a spatiotemporal 
domain to a record of values of defined data types.