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Timestamp Fields

PTAGIS reports all times in Pacific Standard time (PST) in order to be able to compare times from a fish released in a tributary in Idaho to a detection of that same fish on the Lower Columbia River in Oregon.


Timestamp fields in legacy file formats (P3 and earlier tag file formats; Minimon and earlier interrogation file formats) did not have any way to indicate what time zone they were collected in. Data contributors were instructed to set the computer systems used to collect the data with those software programs to PST, but there was no method to ensure that times were actually collected in PST.


Data fields in P4, M4, and M5 files identified as timestamps follow the RFC 3339 profile of the IS0 8601 date format (also known as Date Time Offset), which allow for the use of an offset to Coordinated Universal Time (UTC) to describe an unambiguous moment when a field event occurred. Optionally, the format allows for fraction of seconds to be included which is useful for measuring the latency of real-time operations in the field. PTAGIS converts all timestamps using the offset to PST when loading into the database and rounds to the nearest second for reporting.


Commonly used offset values in the Columbia Basin:

Time Zone Setting



Pacific Standard Time



Pacific Daylight Time



Mountain Standard Time



Mountain Daylight Time




Examples of acceptable ISO 8601 timestamps collected on a system where the clock was set to Pacific Daylight Time:






NOTE: A timestamp with no offset is also technically valid in M5 files, however if no offset is provided, PTAGIS will assume the timestamp is in Coordinated Universal Time (UTC, 00:00). It is recommended that all timestamp values in modern files include the offset to provide precise times for comparison across time zones.

Version: 1.06

Published: 9/28/2022