Yardswithin

Yardswithin is a term used in geospatial computing to describe a proximity query in which distances are expressed in yards. It denotes the operation of identifying features that lie within a given radius from a reference geometry. Although not a formal standard, the concept appears in software documentation, tutorials, and discussions about unit-aware spatial queries in GIS and mapping APIs. The term emphasizes the use of yards as the measurement unit rather than meters or miles.

Mechanics: A yardswithin query accepts a source geometry (such as a point representing a location), a distance in yards, and an optional reference geometry. It returns the subset of features whose distance from the reference geometry does not exceed the specified value. Depending on the data and engine, the distance may be computed in a projected coordinate system or on the ellipsoid, and unit handling may require converting yards to meters (1 yard = 0.9144 meters).

Applications: It is used in retail site selection, service-area analysis, emergency response planning, and location-based search to find nearby resources or features within a defined yard radius. The approach supports various feature types, including points of interest, addresses, or parcels.

Implementation and variants: Many GIS platforms implement similar functionality under different names, such as withinDistance, isWithin, or ST_DWithin. A yardswithin implementation might be realized by converting the distance to meters and using a standard distance function, then filtering results. Some workflows combine yardswithin with spatial indexes for performance.

Limitations: Accuracy depends on the underlying geometry and coordinate system; large distances may require ellipsoidal calculations. Unit conversions can introduce rounding errors. Performance relies on spatial indexes and query optimization.

See also: within, distance, ST_DWithin, isWithin, buffer, spatial index.