Raster Data Models: Examples and Uses (Especially for GATE-Geospatial 2022)

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Raster models are useful for storing data that varies continuously, as in an aerial photograph, a satellite image, a surface of chemical concentrations, or an elevation surface.

This Image Shows Data Stored in a Raster Format

Examples of Raster Data

Data stored in a raster format represents real-world phenomena:

  • Thematic data represents features such as land-use of soils data
  • Continuous data represents phenomena such as temperature, elevation, or spectral data such as satellite images and aerial photographs.
  • Pictures include scanned maps or drawings and building photographs.
  • A cellular based data structure composed of rows and columns for storing images. Homogenous units are called cells or pixels. Mainly used for representing continuous surface e. g. reflectivity of EMR, elevation, rainfall, soil/land use etc.

The raster data model consists of rows and columns of equally sized pixels interconnected to form a planar surface.

Uses of Raster Data Models

  • Geographical variation in the real world is infinitely complex.
  • It would take an infinitely large database to capture the real world precisely.
  • Raster grid cells allow us to approximate the variation over a landscape.
  • Data must somehow be reduced to a finite and manageable quantity by a process of generalization or abstraction.
  • Geographical variation must be represented in terms of discrete elements or objects.
Figure Shows GIS Raster Map Structure

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