Raster

Raster can also be referred to as a grid (or cell-based) data structure. Space is divided into regular cells (usually square) so information is stored as a grid or cells/pixels.

Raster DEM 18kb

• The location of each object is defined by the row and column position of the cells that they occupy.
  
  
• The area of each cell defines the spatial resolution of the data set.
  
  
• The value for each cell defines the type of object present at that location. Each grid cell has attribute values.
  

The two-dimensional array of cells for a particular theme is called a coverage.

Both vector and raster approaches represent spatial information as homogeneous units. In the case of the vector approach, homogeneous units are points, lines and polygons. In the case of the raster approach, homogeneous units are cells.

Advantages and disadvantages of vector data structures