GIS:Spatial Data

In a GIS, the Locational information is provided in maps by using Points, Lines and Polygons. These geometric descriptions are
the basic data elements of a map.

1. Points:
They are represented as a single ‘Dot ‘on the map.

o Points are used to indicate discrete locations.
o They have no length or area at the given scale.
o They usually have a single X, Y coordinate.
o Used to represent a feature that is too small to be displayed as a line or area.

(An example of Points)

2. Arcs / Lines:
Arcs are ordered sets of Points that have the look of a straight line or a curved arc depending upon the feature it describes.

o They have a length but no width.
o They are accompanied by a set of coordinates.
o They are used to represent a geographical feature that is too narrow to have area, such as a stream or a road.

(An example of Lines)

3. Polygons:
They are closed features whose boundary encloses a homogenous area.
o They have an area that is given by the arcs/lines that make the boundary.
o They are used to represent features that have area (e.g. lakes, large cities and islands)

(An example of Polygons)


About Rashid Faridi

I am Rashid Aziz Faridi ,Writer, Teacher and a Voracious Reader.
This entry was posted in GIS, Remote Sensing 101, Statistical Techniques. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.