GPS to LRM: Integration of Spatial Point Features with Linear Referencing Methods, 2001

(2001) GPS to LRM: Integration of Spatial Point Features with Linear Referencing Methods, 2001. Transportation, Department of

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Abstract

Global positioning systems (GPS) offer a cost-effective and efficient method to input and update transportation data. The spatial location of objects provided by GPS is easily integrated into geographic information systems (GIS). The storage, manipulation, and analysis of spatial data are also relatively simple in a GIS. However, many data storage and reporting methods at transportation agencies rely on linear referencing methods (LRMs); consequently, GPS data must be able to link with linear referencing. Unfortunately, the two systems are fundamentally incompatible in the way data are collected, integrated, and manipulated. In order for the spatial data collected using GPS to be integrated into a linear referencing system or shared among LRMs, a number of issues need to be addressed. This report documents and evaluates several of those issues and offers recommendations. In order to evaluate the issues associated with integrating GPS data with a LRM, a pilot study was created. To perform the pilot study, point features, a linear datum, and a spatial representation of a LRM were created for six test roadway segments that were located within the boundaries of the pilot study conducted by the Iowa Department of Transportation linear referencing system project team. Various issues in integrating point features with a LRM or between LRMs are discussed and recommendations provided. The accuracy of the GPS is discussed, including issues such as point features mapping to the wrong segment. Another topic is the loss of spatial information that occurs when a three-dimensional or two-dimensional spatial point feature is converted to a one-dimensional representation on a LRM. Recommendations such as storing point features as spatial objects if necessary or preserving information such as coordinates and elevation are suggested. The lack of spatial accuracy characteristic of most cartography, on which LRM are often based, is another topic discussed. The associated issues include linear and horizontal offset error. The final topic discussed is some of the issues in transferring point feature data between LRMs.

Item Type: Departmental Report
Keywords: Accuracy, Cartography, Coordinates, Data collection, Data storage, Geographic information systems, Global Positioning System, Linear systems, Mapping, Referencing
Subjects: Transportation
Transportation > Research
Transportation > Data and Information Technology
Transportation > Data and Information Technology > Intelligent transportation systems
ID Code: 21323
Deposited By: Iowa DOT Library
Deposited On: 07 Jan 2016 12:50
Last Modified: 07 Jan 2016 12:50
URI: https://publications.iowa.gov/id/eprint/21323