Geostamp for Legal Time Traceability and 4D GIS Applications

Brooks Harris, Cambrea Ezell, and Son VoBa

Abstract: "Transcript of Video Presentation" Legal time and traceability to official time sources are becoming increasingly important. Engineering for civil timekeeping purposes demands timestamps with sufficient metadata to accurately represent local time. Spatial-temporal geographic information systems (GIS), or 4D GIS, provide three dimensions of geographic coordinates to identify a physical space and the fourth dimension referring to time. Geographic location information significantly enhances the provenance of local timestamps. “Traceability” has different meanings. One is of markers for abstract elements such as data, intellectual properties, or events stating when and where those were recorded or taken place. The other is of evidence attached to physical assets attesting to their origin, their transit between locations, and chain of custody. These applications of traceability share universal ground-truths of earth-bound locations and UTC timekeeping. This paper describes an aggregate of two efforts that were presented at past PTTI conferences in 2019 and 2020: Common Calendar Timestamp system (CCT) by EdlMax and modern timekeeping for IT solutions by Sync-n-Scale. This collaboration introduces “geostamping” as a tool for meeting traceability needs across multitude of industry segments. A geostamp is an atomic data element consisting of a geographic location (e.g. cartesian latitude, longitude, and altitude) and CCT timestamp. Its authenticity is established by combining a demonstrably trusted geographic coordinate and a UTC-traceable accurate timestamp. A geostamp is human readable and technically accurate for interpretive and forensic purposes. It can be examined afterwards and away from its issuing system for determination of where and when it was recorded. This characteristic makes it suitable for general and legal purposes where time recording is used for tracking and auditing. Trusted geostamps are also suitable for a wide range of 4D GIS applications in machine learning, artificial intelligence, data analytics and Blockchain distributed ledgers. The CCT specification has been extended to include geographic coordinates to support geostamp. Organization of its code base has been refined to provide clear guidance on the interpretation of IERS Leap Seconds, IANA Time Zone Database and geographic information, algorithms for UTC calculation, binary and character timestamp formats, methods for populating and reading the two formats, and a high-level API for convenient manipulation and calculation of calendaring operations. The C/C++ reference implementation has been updated to accommodate the full breadth of civil time data provided by Tz database. It is now also available to the community on GitHub. The authors hope these improvements will find support in general adoption and look forward to engaging with the community for future features.
Published in: Proceedings of the 52nd Annual Precise Time and Time Interval Systems and Applications Meeting
January 25 - 28, 2021
Pages: 167 - 184
Cite this article: Harris, Brooks, Ezell, Cambrea, VoBa, Son, "Geostamp for Legal Time Traceability and 4D GIS Applications," Proceedings of the 52nd Annual Precise Time and Time Interval Systems and Applications Meeting, January 2021, pp. 167-184.
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