Question

Discuss raster data formats. Give an example.

Answer 1

The raster data format represents geographical objects as a continuous grid of cells organised into rows and columns. Instead of tracking precise coordinate boundaries, it divides the entire map space into a matrix of small, equal-sized squares called pixels. Each cell contains a single numerical value representing a particular geographical attribute.

1. Grid Matrix: The entire geographic area is covered by a uniform mathematical layout of interlocking horizontal rows and vertical columns.
   Example: A scanned topographic sheet of a district represents the entire landscape using a uniform mathematical layout of interlocking rows and columns.
   
2. Pixel/Cell Value: Every single cell acts as an independent unit that holds a specific numeric code representing the ground feature or characteristic found at that spot.
   Example: A land cover map uses a single grid cell with a specific numeric code to represent a ground feature, such as a forest patch or a water body, at that location.
3. Spatial Resolution: The actual size of the ground area represented by a single square cell determines the clarity and detail of the entire data layer.
   Example: A digital elevation model utilises a single square pixel cell containing a specific altitude value to determine the exact height of that ground section above sea level.