Where does grid collide?

A regular arrangement of discrete points or cells laid over a continuous domain so that a differential equation can be solved by approximating it at those points, also called a mesh or coordinate grid. Thompson's survey of grid generation in computational fluid dynamics describes how such a grid is built to fit a region and to control the spacing of its nodes. Here the referent is a mathematical construction, a set of sample locations with coordinates, and the unit is the point set covering the domain. The lines are grid lines that carry nothing physical; they only index where the solution is computed. It shares the word and the look of regular crossing lines with the power network and the street plan, but nothing travels along it.[1]

Unit

A set of discrete points or cells covering a domain

Recovery means

Not applicable

Measured by

Node spacing, cell count, and mesh quality over the computational domain

A street layout of roughly perpendicular, intersecting streets forming rectangular blocks, the plan a city adopts by design rather than letting streets grow organically. Southworth and Ben-Joseph trace how street standards, including the move toward and away from the grid, shaped the form of American suburbs. The referent is a real city's network of roadways, and the unit is the street layout with its blocks and intersections; the lines are streets that people and vehicles travel. What marks this meaning is that the regularity is a planning choice with consequences for connectivity, walking, and traffic, not a computational convenience and not an electricity network.[2]

Unit

A city's street layout of intersecting streets and blocks

Recovery means

Not applicable

Measured by

Block size, intersection density, and connectivity of the street network

An imaginary overlay that divides a frame into thirds horizontally and vertically, giving two lines each way and four intersections, used as a guideline for placing subjects in a photograph or painting. Amirshahi and colleagues tested whether images actually follow this rule and how it relates to judged aesthetics, treating the grid as a compositional heuristic rather than a law. The referent is a rule applied to a single image, and the unit is the overlay on one frame; the lines mark suggested placements and carry nothing and connect to nothing. It is the faintest grid of the four: no current, no computation, no roads, only a convention for where the eye is guided.[3]

Unit

A compositional overlay on a single frame

Recovery means

Not applicable

Measured by

Placement of salient content near the lines and intersections that split the frame in thirds

In art history, grid refers to the grid as an emblem of modernist art's claim to autonomy, flat and turned away from nature and narrative. This meaning comes from Krauss (1979) in October.[4]

Unit

Recovery means

Measured by