Alongline

Alongline is a term used in various technical fields to describe data, measurements, or features that lie along a defined line or path. It is often encountered in geospatial science, surveying, and related disciplines, where the focus is on information collected or modeled along a linear feature rather than across an area.

In surveying and cartography, alongline data are collected or constructed along a centerline or another preselected line, such as a road, pipeline, coast, or railway. This enables the creation of longitudinal profiles, gradient analyses, or cross-sectional studies that reflect how properties change along the route or alignment. Alongline representations can support infrastructure planning, monitoring, and impact assessments by concentrating phenomena along a specific trajectory.

In geographic information systems and remote sensing, alongline processing involves extracting or aggregating information along a polyline. Examples include sampling raster values along a line to generate a value profile, projecting point measurements onto a line, or deriving attributes that vary along the feature’s length. This approach is useful for analyzing spatially varying phenomena that are best understood in relation to a linear feature.

Etymology notes: alongline is typically written as a compound referring to data "along" a "line"; it may also appear as along-line in some sources. Its exact usage can vary by discipline, and it is not always standardized.