Overview
In GIS, we primarily work with two types of data models: vector data and raster data. This page will provide you with an overview of both types, as well as discuss information about other sources and types of data that are commonly encountered in GIS.
Vector Data
Vector data represent discrete data values, or data values that have seperate, distinct units that we can count. In GIS, we store vector data using:
- Points, which represent distinct locations in space.
- Lines, which represent connected linear values.
- Polygons, which represent connected and bounded areas.
Some examples of data stored as vector values include:
- Points representing the location of hospitals.
- Lines representing a river.
- Lines representing a highway.
- Polygons representing town boundaries.
From: https://id.land/blog/raster-vs-vector-data-the-ultimate-guide
Raster Data
Raster data can represent discrete values, as well as continuous data values, or values that fall within an infinite spectrum of numbers that can be measured to any decimal place. In GIS, we store raster data using cells/pixels organized into a grid, and each cell represents a data value.
Some examples of data that are stored as rasters include:
- Temperature
- Elevation
- Aerial Images
- Soil types
- Satelite imagery
From: https://www.researchgate.net/figure/The-pixels-in-a-raster-layer_fig4_352709886
Imagery and Remote Sensing
Imagery is a type of raster data captured by cameras, drones, planes, and satellites of our world. This includes aerial imagery, digital elevation models (DEMs), and satellite imagery such as LandSat. A significant amount of this data is collected via Remote Sensing, which is the process by which satelites and other aircraft collect data and information about our world from a distance using sensors that can meaure the electromagnetic spectrum.
The use of imagery and remote sensing in GIS is a powerful way to meaure and monitor changes in the world around us, including climate, land use, weather, migration, and sea-levels.
Digitized Images
Another type of raster imagery includes digitized and georeferenced maps, or paper maps that have been scanned and referenced to their real-world location using GIS tools and reference points. Using this process, historical maps can be included in projects, visualizations, and even analysis. This process allows modern-day GIS users to expand their projects to include historical data that existed before the widespread use of GIS, and opens up many possibilities for applying GIS methods to the humanities.
Time and Temporal Data
Many GIS systems have the capacity to store temporal data values, such as times, days, months, weeks, and years. These can be represented and visualizaed in several ways:
- Statically, using seperate maps to represent your data at specific points in time.
- Using a slider on a computer-based mapping application.
- Using animation.
Learn more about storing and including temporal values in GIS:
- Tutorial on Visualizing Temporal Data in ArcGIS ProLearn how to visualize temporal data on tourism in New Zealand using a time-slider.
