Gis Data Types

A geographical Information System has the capability to handle a wide rage of data e.g. roads, rivers, heights, lakes, rainfall, temperature e.t.c

For effective analysis and manipulation the data above is grouped into two categories i.e Vector and Raster data.

Vector Data

It can be categorized into 3 main types i.e. points, lines, and polygons

Trees, River and lake represented as points, line and polygon respectively

Points

Points are zero-dimensional objects that contain only a single coordinate pair.
They are used to model singular, discrete features such as trees, houses, sample data e.t.c
When features are too small to be represented as polygons, points are used. e.g towns on a country map.


Lines 
These are one dimensional features which are formed by  connecting points. 
Lines are used to represent linear features such as roads, streams, rivers, boundaries etc.

Polygons
Polygons are two dimensional features created by joining lines to form a closed area feature.
They are used to represent features such as  property boundaries,regions,lakes, zones e.t.c

RASTER DATA

Raster data is used in a GIS applications to represent continuous information that cannot easily be divided into vector features. 
The  real world phenomena is divided into cells which can either be rectangular or triangular.
This data model is used to represent phenomena for which each point has a value on earth.(continuous fields)
Such data that may be represented in this form includes aerial photography, elevation data, satellite imagery,temperature e.t.c.

Satellite imagery acquired from optical remote sensing