This page defines the key terms used in Raster SQL. Each term is tagged with its knowledge domain to help you orient quickly — whether you are coming from a GIS background, a database background, or a remote sensing background.
| Term | Domain | Definition |
|---|---|---|
| raster object | [data model] | A regular grid that represents a space. Each cell in the grid is assigned an attribute value to model a real-world entity. Common examples include satellite images, digital elevation models (DEMs), and pictures. See also: *cell/pixel*, *band*. |
| cell/pixel | [data model] | The smallest unit of a raster object, also called a pixel. The data type of a cell varies by raster object: byte, short, integer, or double. See also: *raster object*, *band*. |
| band | [data model] | A single characteristic of a raster object, represented as a matrix of cell values. A raster object can have one or more bands. See also: *cell/pixel*, *interleaving*. |
| chunk | [storage] | A portion of a raster object. The chunk size is configurable — for example, 256 × 256 × 3. |
| pyramid | [performance] | A set of downsampled versions of a raster object. A pyramid can contain one or more downsampled layers. Consecutive pyramid layers are downsampled at a scale of 2:1. Layer 0 stores the raw data. See also: *pyramid level*. |
| pyramid level | [performance] | A single layer within a pyramid. See also: *pyramid*. |
| mosaic | [operation] | The operation that integrates one or more raster objects into an existing raster dataset. |
| interleaving | [storage] | The arrangement of pixel data within a raster object. The interleaving types include band sequential (BSQ), band interleaved by pixel (BIP), and band interleaved by line (BIL). See also: *band*. |
| world space | [coordinate system] | The geographic coordinates of a raster object. See also: *raster space*. |
| raster space | [coordinate system] | The pixel coordinate system of a raster object. The top-left corner of the raster object is used as the starting point. See also: *world space*. |
| metadata | [data model] | The descriptive properties of a raster object, including its spatial range, projection type, and pixel type. Remote sensing platform metadata is not included. |