All articles starting with S

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.

Oct 10, 2026

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 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.

Spatial sampling design

Spatial sampling design is the set of procedures for choosing which locations to observe in a geographically distributed population, organized around design-based and model-based inference.

Spatial transcriptomics

Spatial transcriptomics is a family of molecular biology methods that maps gene expression across intact tissue while recording each transcript's position, introduced by Patrik Ståhl in 2016.

Spatially fractionated radiation therapy

Spatially fractionated radiation therapy (SFRT) is a radiotherapy technique delivering high-dose peaks separated by low-dose valleys to shrink bulky tumors, including 2D GRID therapy and 3D lattice radiotherapy.

Spatially offset Raman spectroscopy

Spatially offset Raman spectroscopy (SORS) is a technique that collects Raman light away from the laser spot, chemically analyzing buried layers and sealed containers without sample preparation.

Spatially resolved spectroscopy

Spatially resolved spectroscopy records a spectrum at every location across a sample, turning variation in composition or structure into an image rather than a bulk average.

Spatio-temporal clustering

Spatio-temporal clustering is a data mining method that groups points close in both space and time, applied to GPS tracks, crime hotspots, and Twitter event detection.

Spatio-temporal data mining

Spatio-temporal data mining (STDM) extracts useful patterns from large datasets where every measurement carries a location and a timestamp, such as GPS trajectories, sensor readings, and evolving weather maps.