Data Conversion

Conversion of data format –

The conversion of vector data to raster data is called as rasterization. For ex. coverage to grid..



The conversion of raster data to vector data is called as vectorization. For ex. A grid to a polygon coverage.



Both type of conversions require the use of computer algorithms.

Steps involved in rasterization

Rasterization involves three basic steps.

1. The first steps is to set up a grid with a specified cell size to cover the area extent of the coverage and to assign initially all cell values as zeros.
   
   
2. The second step is to change the values of those cells that corresponds to points, lines or polygon boundaries. The cell value is set to one for a point, the line’s value for a line and the polygon’s value for a polygon value.
   
   
3. The third step is to fill the interior of the polygon outline with the polygon value.

Errors form rasterization depend on the computer algorithms and the size of raster cell .

Steps involved in vectorization

This process involves conversion of raster data into vector data. In short the process involves the following steps

1. Raster line thinning,
   
   
2. Vector line extraction,
   
   
3. Topological reconstruction,
   
   
4. Line smoothing.