Raster vs Vector
EquatorStudios | Feb 1, 2022
494 words | 2 min read
The Great Debate
Ah yes… Raster vs Vector? A question that has divided the GIS community for years, with one side proclaiming Raster as “the master” and the other insisting Vector as “more corrector”. Ultimately, the answer to this question may never be indefinite. Depending on the project demands, you might find yourself using the Vector data format, or the Raster data format, or even both. In this blog, we’ll walk you through what Raster and Vector are, as well as the various advantages and disadvantages they can respectively bring to your GIS project.
What are Data Models in GIS?
Spatial data models in GIS are understood as a set of mathematical and other constructs that are used to generate a computer-based representation of geographical entities, phenomena, and processes, within the real world. The two basic data models in GIS would be – as you might have guessed – the Raster and Vector data models.
Raster Model Projecting Crops
Raster Data Model
The Raster Data model is most often associated with continuous data – a phenomenon with no defined boundary. This is because Raster goes about projecting data by dividing the site into even square cells (a grid or a DEM). Every grid possesses a unique value and is rooted to the Earth’s surface, with its corners conforming to their geographic coordinates in the real-world. Whilst the Raster model is identified with continuous data, it can also represent discrete data, through a collation of various cells or a single cell. Three sources of Raster data are satellite imagery, aerial photos, and scanned maps.
Vector Model with Points, Lines, and Polygons (Source: wikimedia.org)
Vector Data Model
The Vector data model is most suited to representing data possessing discrete boundaries (discrete objects). There are three recognized categories of Vectors by which features are projected: points, lines, and polygons. Every feature in the Vector data model must have a clearly defined geographical position. Given the nature of the projection, the Vector data model tends to have quite a few empty spaces – as opposed to its raster counterpart where data is continuous.
So… Raster or Vector?
Each data model has its uses. Depending on the project needs, you may find yourself using one exclusively, or both interchangeably. We have outlined below some of the advantages and disadvantages of both so you can decide for yourself:
|Raster – Advantages||Vector – Advantages|
|Raster – Disadvantages||Vector – Disadvantages|