What is Spatial Data Model ?

GIS data is spatial data control. Any functionality that makes environmental GIS analysis is distinguished from others is that rooted in the authenticityographic phe of spatial data. Spatial data describe genomena associated with location relative to the Earth's surface (georeferenced), the digital format of the sightings map, the shape coordinate points, and symbols that define the elements of delineation (cartography), and linked to attribute data stored in tables -table as an explanation of the data spatial (georelational data structure).There are 2 models of spatial data, vector data models and raster data models.

• Vector data models

Vector data model represents each feature into a row in the table and shape features are defined by the point x, y in space. There are 3 types of vector data model :

1. The point is the simplest graphical representation for an object. This representation does not have the dimensions but can be identified on maps and can be displayed on the monitor screen using symbols.
2. The line is a linear form that will connect at least two points and used to present the two-dimensional objects. Object or entity can be represented with lines such as roads, rivers, electricity, drainage.
3. Polygons used to represent two-dimensional objects, for example: Islands, administrative areas, boundaries of land parcels is the entity which is generally represented as a polygon. At least one polygon bounded by three lines between the three points which converge to form the field. Polygons have a broad spatial properties, around isolated or connected with the other, incised (intended), and overlapping.

• Raster data models

This spatial data model represents the features into a sustainable form of matrix. Each layer represents one attribute (although other attributes can be included into the cell matrix). Raster spatial entities are stored in the layer of functionality that are related with elements of maps. Examples of sources of spatial entities are raster images (example :Ikonos).

What is Geographic Information Systems

GIS (Geographic Information System), after referred to as GIS (Geographic Information System) is a technology that serves as an essential tool in the store, manipulate, analyze and display the return of natural conditions with the help of attribute and spatial data.
Represent real-world model in GIS is twofold. First is the type of spatial data that represent spatial aspects of the so-called position data, space coordinates. Second is the type of data that represents a descriptive aspect of the phenomenon being modeled is called non-spatial data or attribute data.