Answer:
1. Two advantages of the raster data model over vector data are:
- It can handle continuous phenomena or data that varies smoothly over space such as temperature, elevation, or rainfall. Raster data represent the surface or volume of a geographic space as a regular grid of cells or pixels, where each pixel has a value that corresponds to the attribute of interest. This allows for more accurate and detailed analysis and visualization of complex patterns or trends that involve spatial and temporal dimensions.
- It can process large datasets efficiently and quickly, especially when dealing with spatial operations that require overlay, proximity, or aggregation. Raster data can be stored as multi-band images, where each band represents a different attribute or layer, such as vegetation cover, land use, or slope. This allows for the integration and comparison of different types of information in a single format, which facilitates decision-making and monitoring of environmental changes.
2. The two ways digital data can be compressed are:
- Lossless compression: This method reduces the size of the data file without losing any information or quality. It achieves this by eliminating redundant or unnecessary bits or codes in the data stream, using algorithms such as Huffman coding or Lempel-Ziv-Welch. This results in a smaller file size that can be reconstructed to the original data file without any loss or corruption. This type of compression is useful for data that needs to be stored or transmitted efficiently and reliably, such as text files or program code.
- Lossy compression: This method also reduces the size of the data file, but at the cost of some loss or degradation of the information or quality. It achieves this by discarding some of the less important or perceptually significant bits or components in the data stream, using algorithms such as discrete cosine transform or wavelet transform. This results in a smaller file size that may exhibit some artifacts or noise when reconstructed to the original data file. This type of compression is useful for data that can afford some loss or distortion without affecting its usefulness or value, such as audio or video files.
3. The advantage of data compression is:
- It saves storage or transmission space and bandwidth, which can reduce costs, increase efficiency, and facilitate access to information. Compressed data files require less memory or disk space to store, and less time or network resources to transmit or download. This can be especially important for big data, multimedia, or web-based applications that deal with large or complex data sets. Compression can also improve the speed and performance of some operations, such as data transfer and rendering, as the compressed data can be processed more efficiently and quickly.