Bitmap
A bitmap is a representation that stores information as a grid or set of bits, such as pixel values or selected storage locations.
Just Use Postgres!
A bitmap is a compact structure that records table-row or table-page locations selected by an index condition.
- How it is used
- Coordinates bitmap index and heap scans to batch table-row retrieval for indexed conditions.
- How deep it goes
- Explains two-phase execution and exact versus lossy locations, without developing bitmap storage internals.
- Examples
- Uses PostgreSQL EXPLAIN plans for hash-index lookups, multi-value IN queries, and GIN-backed full-text searches.
- What you can do after
- Diagnose/debug with it by reading Bitmap Index Scan, Bitmap Heap Scan, heap-block, and recheck-plan details.
Geometry for Programmers
A bitmap is a digital image represented as a grid of individually addressable pixels.
- How it is used
- Uses pixel grids as inputs for image upscaling, smoothing, and extracting continuous geometric boundaries.
- How deep it goes
- Defines pixels, derives localized interpolation, and implements smoothing and contour fitting, but does not develop bitmap storage formats.
- Examples
- Uses a cat-eye upscale and a 16×16 grayscale image converted into a smooth threshold contour.
- What you can do after
- Build it from scratch using localized interpolation to smooth a bitmap and iterative geometry to extract a curved contour.
Related concepts
- bitmap heap scanused by · A bitmap heap scan reads table rows identified by a bitmap produced by an index scan and may recheck conditions for lossy pages.
- continuous color functionproduces · A continuous color function maps spatial coordinates to color values while varying continuously across the image domain.
- pixelhas part · A pixel is either a discrete sample carrying visual information at a position in a digital image or a reference unit used to express rendered dimensions.
- bitmap index scanproduced by · A bitmap index scan is a query-plan operation that uses an index to build a bitmap of matching row locations before retrieving the corresponding table rows.
- normal mappingused by · Normal mapping is a rendering technique that uses a texture to perturb surface normals without changing the underlying geometry.
- vectorproduces · A vector is an ordered collection of components representing an element of a vector space.
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