VECTOR MODEL

Vector data are discrete. It store information in x, y coordinate format. There are three types of
Vector data: Lines, Points and Area

Advantages of the vector model :

٠ Need a small space or place for storage data (disc).

* One layer can be connected with or many attribute for saving the space of storage data.
* Easily makes connection between topology and network.

* Have a high spatial resolution.

* Graphic representation spasial data closely likes man-handed map.

«Very good in correction limits, apparent and clear for making administration maps and
ownedlands.

* Easily for making projection and coordinates transformation.
Disadvantages of the vector model :

* Have a complex data structures.

* Data not easily for manipulates.

° Users cannot created owned programs for applications needed. In this case, a complex of the
vector data structure and analysis and function procedures needs high capability because its more
difficult and complicated— users must buy a software because of expensive technology.

* Needs a long time only for all the process. Vector data often out-of-date.

* Not compatible with remote sensing images data.

* Needs more an expensive software and hardware.

* Overlay vector layers with simultant needs a long time

9.a) (Explain any 10, 10x1= 10)

Sources of error into three main categories:
1. Obvious sources of error.
2. Errors resulting from natural variations or from original measurements.
3. Errors arising through processing 1 Obvious Sources of Error

a. Age of data

Data sources may simply be to old to be useful or relevant to current GIS projects. Past
collection standards may be unknown, non-existent, or not currently acceptable. For instance,
John Wesley Powell's nineteenth century survey data of the Grand Canyon lacks the precision
of data that can be developed and used today. Additionally, much of the information base may