New date-time columns added to sensor positions file in Instrument System downloads

Two new columns will soon be added to the sensor_positions metadata file included in Terrestrial Instrument System (TIS) and Aquatic Instrument System (AIS) download packages. The new columns, effectiveStartDateTime and effectiveEndDateTime, specify the beginning and ending date-times for which the geolocation information provided in each record (row) is valid for both the sensor and its associated reference location.

Each Instrument Systems (TIS and AIS) data product download package includes a metadata file containing sensor_positions in the filename. This file provides the geolocation history for every sensor used to collect data for the product. Each record includes geolocation information for a sensor location and its associated reference location, from which sensor positional offsets are defined. 

The geolocation metadata for the sensor and its reference location can change independently over time, resulting in one record for each period during which their date ranges overlap. The date range for the sensor location is defined by the positionStartDateTime and positionEndDateTime columns, while the date range for the reference location is defined by the referenceLocationIDStartDateTime and referenceLocationIDEndDateTime columns. Previously, users had to combine these date ranges to determine the effective date range represented by each record. With this update, the effective date range is provided directly through the new effectiveStartDateTime and effectiveEndDateTime columns.

The new effectiveStartDateTime and effectiveEndDateTime columns will be included in the sensor_positions file of all newly published download packages as of this data notification. These columns will also be added to the full historical record for all Instrument Systems data products as part of the 2027 NEON Data Release, scheduled for publication in late January 2027.

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