All articles A–Z
519,064 articles
Spathoglottis plicata
Spathoglottis plicata (Philippine ground orchid, anggrek tanah) is a terrestrial Orchidaceae species described by Blume in 1825, native from tropical Asia to the Pacific, cultivated as an ornamental, and rated invasive in Florida by UF/IFAS.
Spathognathodus
Spathognathodus (Branson & Mehl, 1941) is an extinct conodont genus of bladelike chordate fossil elements with a mid-unit basal cavity, ranging Devonian to Pennsylvanian and ancestral to platform genera like Pseudopolygnathus.
Spatial ability
Spatial ability: the capacity to generate, retain, and manipulate visual-spatial imagery; the CHC Gv factor with 11 first-order factors. Key facts: sex differences (d = 0.155 in visual-spatial working memory), STEM prediction, trainability, and tests like the Mental Rotations Test.
Spatial analysis
Spatial analysis, also called spatial data analysis, examines the locations, patterns, and relationships of features in geographic data; its statistics incorporate space directly, unlike traditional statistics.
Spatial atomic layer deposition
Spatial atomic layer deposition (spatial ALD) is a thin-film deposition method that separates ALD's two half-reactions in space rather than time, raising throughput while keeping subnanometer thickness control.
Spatial audio
Spatial audio is a family of recording and playback techniques that let listeners perceive sound sources in three-dimensional space, most commonly on headphones using head-related transfer functions.
Spatial autocorrelation
Spatial autocorrelation is the positive or negative correlation of a variable with itself across geographic space, so similar values cluster on a map; it is measured by Moran's I and matters for regional economic data.
Spatial autoregressive model
The spatial autoregressive (SAR) model is a regression model where each location's outcome depends partly on neighboring outcomes through a spatial weights matrix, used for property values.
Spatial capture-recapture
Spatial capture-recapture, also called spatially explicit capture-recapture (SECR), is a statistical method in ecology that estimates animal density and abundance from capture histories and detector coordinates.
Spatial clustering
Spatial clustering is a family of data-analysis methods that groups observations so points close together in geographic location, and often similar in attributes, fall into the same cluster.
Spatial coherence
Spatial coherence is the phase correlation between a light wave's field at two transversely separated points, measured by fringe visibility and set by the source's angular size.
Spatial competition
Spatial competition is a branch of economics in which firms and consumers occupy a space, so distance gives firms localized market power and location becomes strategic.
Spatial database
A spatial database is a database management system extended with types, functions, and indexes for storing and querying geometric objects such as points, lines, and polygons.
Spatial disorientation
Spatial disorientation is an erroneous perception of one's position and motion relative to the earth, common in flight and a leading cause of fatal aviation accidents.
Spatial disorientation in aviation
Spatial disorientation in aviation is a pilot's inability to correctly interpret an aircraft's attitude, altitude, or airspeed when vision and the inner ear give misleading cues in flight.
Spatial Durbin model
The spatial Durbin model (SDM) is a spatial econometric regression in which the outcome depends on neighbors' outcomes and neighbors' covariates, nesting the SAR, SLX, and SEM models.
Spatial econometrics
Spatial econometrics is the subfield of econometrics that handles spatial dependence and spatial heterogeneity in regression models for cross-sectional and panel data, traced to Paelinck and Klaassen (1979) and Anselin (1988).
Spatial epidemiology
Spatial epidemiology is the subfield of epidemiology that studies where disease risk is elevated, combining disease mapping, spatial statistics, and disease modeling to find patterns and clusters.
Spatial error model
The spatial error model is a spatial regression model where spatial dependence enters through autocorrelated errors, introduced by Ord in 1975 and popularized by Cliff and Ord in 1981.
Spatial filter
A spatial filter modifies a two-dimensional signal by its spatial frequency content, as in digital image processing or as a lens-and-pinhole assembly cleaning laser beams.
Spatial frequency
Spatial frequency is the number of cycles of a periodic pattern per unit distance, the spatial analog of temporal frequency, used in optics, imaging, and vision science.
Spatial frequency domain imaging
Spatial frequency domain imaging (SFDI) is a noncontact, wide-field optical technique that projects sinusoidal light patterns onto tissue to map absorption, scattering, hemoglobin, and oxygen saturation, reported in 2005.
Spatial intelligence
Spatial intelligence, in Fei-Fei Li's usage, is AI that understands, generates, and interacts with complex 3D worlds, driving World Labs and a 2024–2026 wave of world-model companies.
Spatial intelligence (psychology)
Spatial intelligence (spatial ability) in psychology: the capacity to generate, retain, and manipulate mental images, studied via tests like the Vandenberg Mental Rotations Test and PSVT:R; a CHC-theory factor (Gv) predicting STEM achievement and trainable through interventions.
Spatial interaction model
A spatial interaction model is a mathematical model predicting flows of people, goods, or information between locations, used in transport planning, economics, and epidemic modeling.
Spatial light modulator
A spatial light modulator (SLM) is a device that controls the intensity, phase, or polarization of light pixel by pixel, used in wavefront correction and imaging.
Spatial memory
Spatial memory: memory for locations, landmarks, and routes, based on hippocampal place cells, entorhinal grid cells, and primate spatial view cells; supports navigation and episodic memory, and is an early marker in Alzheimer's disease.
Spatial modulation
Spatial modulation is a MIMO wireless technique where information bits are carried both by a signal symbol and by the index of the one active transmit antenna.
Spatial normalization (neuroimaging)
Spatial normalization is a neuroimaging preprocessing method that warps brain scans from different subjects into a common reference space, underpinning voxel-based morphometry and fMRI group analysis.
Spatial pyramid matching
Spatial pyramid matching (SPM) is a computer vision technique that compares images by matching histograms of local features over increasingly fine sub-regions, introduced at CVPR 2006.