Digital Raster
A digital raster is a method of representing a digital image, as well as digital terrain, using a matrix of individual pixels. Each pixel holds an individual color or gray scale value, which, when rendered together, forms a complete digital image. Digital raster technology can be used to achieve accurate representation of terrain, imagery and other spatial data.
The most common use of digital raster technology is for making high resolution maps and satellite imagery. Digital raster imagery is widely used in geographic information systems (GIS), remote sensing and for creating other cartographic products such as topographic maps. Digital raster techniques also play a vital role in weather prediction and climate change analysis.
Digital raster images are formed by using a technique called “sampling and quantizing”. In this process, the raster image is divided into pixels, and each pixel is given a specific color or gray scale value based on the sample data. The resolution of the image is determined by the size and number of these pixels. The higher the resolution, the more detailed the image will be. The image can then be saved in various formats, such as Joint Photographic Experts Group (JPEG), Windows bitmap (BMP), and Tagged Image File Format (TIFF).
Digital raster images can be used for many different applications. They may be used as base maps for web-based mapping applications, for processing satellite images, for creating digital elevation models, for identifying landmarks and for interpreting aerial images. Digital raster images may also be used for a variety of other purposes, including surveillance, traffic monitoring, law enforcement, tracking endangered species and auto-steering systems.
When used in a GIS, digital raster images can be used to create a wide range of maps, from basic educational maps to complex 3-D visualizations. Digital raster images may also be used to perform spatial analysis, such as land cover and vegetation change analysis. By combining various datasets, such as topographic maps, aerial photographs, and satellite images, an analyst can create a three-dimensional view of a particular area. This technique is often used in disaster analysis and in other environmental applications.
Digital raster techniques are increasingly used in geospatial analysis and decision-making. These techniques provide a valuable tool for making more informed decisions, while also reducing costs due to the automated processes involved. Digital rasters are also easy to manipulate, store and share, making them an ideal format for transmitting digital data.
