overlaid

Overlaid is the past participle of the verb overlay, meaning to place something on top of something else, often partially or completely covering it. The verb can be transitive, as in overlaying an image with another or overlaying patterns on fabric. The spelling overlayed is also used, but overlaid is the standard form in contemporary English.

In graphic design and image processing, overlaid elements are common for composing images, text, or graphics on top of a base layer. Compositing often employs alpha channels and masks to control transparency and blending between layers, producing effects such as captions, highlights, or visual textures.

In cartography and geographic information systems, multiple data layers are overlaid to create a single, informative map. Examples include overlaying roads on satellite imagery, or layering demographic data over terrain. The technique helps users compare spatial relationships and extract integrated information.

In data visualization, overlaid charts and graphs display multiple data series on the same axes. This allows direct comparison and can reveal correlations or trends that are not evident when data series are shown separately.

In computing, overlaying refers to techniques where code or data is loaded into the same memory space at different times to conserve memory. Although less common in modern systems, historical and specialized software used overlaid segments to optimize resource use.

Overall, overlaid conveys the notion of adding a surface, layer, or element atop another to enrich context, convey information, or achieve a visual or functional composite.