DLG Digital Line Graph

Specifications

Digital Line Graph (DLG) is a map format that provides greater convenience for zooming, panning, querying, checking, measuring, and overlaying. With a small data volume and easy layer management, it can rapidly generate thematic maps, and is thus also known as Digital Thematic Information (DTI). This data meets various spatial analysis requirements of Geographic Information Systems (GIS) and is regarded as intelligent data. It allows arbitrary data selection and display, and can be overlaid with other geospatial products to facilitate analysis and decision-making. The technical characteristics of Digital Line Graphs (DLG) include: geographic content, sheet partitioning, map projection, accuracy, and coordinate systems that are consistent with topographic maps of the same scale. Graphic output is in vector format, remaining distortion-free at any zoom level.

DLG is a vector dataset containing core topographic features (including settlements, transportation, hydrography, independent landmarks, pipelines, boundaries, etc.). It stores various features in categorized layers while preserving spatial relationships and associated attribute information between features. Primary acquisition methods include plane table surveying, full-field digital surveying, GPS surveying, map digitization, and photogrammetry. DLG satisfies various spatial analysis requirements of Geographic Information Systems (GIS) and is regarded as intelligent data. It allows arbitrary data selection and display, and can be overlaid with other products to facilitate analysis and decision-making.