In this video, I can show the effect (Quality of the image) of the “pyramid layer” on an image in ERDAS Imagine Software (9.2).
Pyramids are used to improve display performance. They are a downsampled version of the original raster dataset and can contain many downsampled layers. Each successive layer of the pyramid is downsampled at a scale of 2:1.
Pyramids can speed up the display of raster data by retrieving only the data at a specified resolution that is required for the display. With pyramids, a lower-resolution copy of the data displays quickly when drawing the entire dataset. As you zoom in, levels with finer resolutions are drawn and performance is maintained because you're drawing successively smaller areas. The database server automatically chooses the most appropriate pyramid level based on the user's display scale. Without pyramids, the entire dataset must be read from disk and resampled to a smaller size. This is called display resampling and occurs when the display is refreshed.
Pyramids only need to be built once per raster dataset. After that, they are accessed each time the raster dataset is viewed. The larger the raster dataset, the longer it takes to create the set of pyramids, but the display will be faster and you will save time in the long run.
Although you are not able to build pyramids on raster catalogs, it is possible to build pyramids for each raster dataset within a raster catalog. Mosaic datasets are similar to raster catalogs. You can build pyramids for each raster dataset within a mosaic dataset, and you can build overviews for a mosaic dataset using tools in the Mosaic Dataset toolset
Reference: 1) community.hexagongeospatial.com/t5/IMAGINE-Q-A/Why-do-I-have-to-calculate-pyramid-layers-again-in-IMAGINE/ta-p/6520
2) desktop.arcgis.com/en/arcmap/latest/manage-data/raster-and-images/raster-pyramids.htm
3) bynder.hexagon.com/m/4cce2965b2270e54/original/Hexagon_GSP_ERDAS_IMAGINE_2020_Release_Guide.pdf
This video can help you to understand the impact of the “Pyramid Layer” on an image in ERDAS Imagine Software (9.2).
Thank You,……………..