The LTER Network Unit Registry is a web service-enabled database of standardized scientific units in use at different levels of the LTER research community. The goal of the Unit Registry project is to provide a central tool that is useful to distributed end users as well as application developers. The search interface you are currently using is a client built over the Unit Registry web service - one of many ways that users and applications can interact with the Unit Registry. By creating a database that can be accessed by users and also incorporated into site- and network-level data systems, we aim to support current and future scientific projects through data comparability, integration, and synthesis.

Using the Query Interface

The query interface on this site provides a simple way to browse and search for units, view them, and download them in multiple common formats. To begin your search, choose the Basic Search or Advanced Search tab. The Basic Search will take any text input and compare it to all unit names, descriptions, quantities, and scopes. The Advanced Search allows you to specify text to search for in the name and/or description, as well as the option to limit the results by scientific quantity (i.e. type of unit) and scope.

After submitting a search, a list of units with their abbreviations and descriptions will appear. Clicking on a unit will show you more information. This includes the scientific quantity represented by the unit, information on the unit's conversion to an International System of Units (SI) base unit, and groups within the LTER community currently using the unit (scope). Also, units flagged with a alert symbol have been deprecated, and information on the accepted and preferred replacement is included in the unit definition.

After searching, a list of units can be saved by using the Export Current Results option at the bottom of the page. The format of the saved file is determined by the drop-down box to the left of the button. This option will create a file in the requested format containing the current result set, as well as related information on quantities and scopes (where permitted by the output format).

The Unit Registry for Developers

The Unit Registry web service can be accessed not only through this query interface but from other applications as well. The web service uses a REST model over the HTTP protocol - the same protocol web browsers use for viewing pages. This means that any web browser can be used to send requests to the service and view the results. For other applications to use the Unit Registry web service, they need to be able to open a file over the HTTP protocol. Our web service examples page shows methods for doing this in several popular languages.

As a developer, you'll also need to understand the syntax for making calls to the Unit Registry web service. The complete syntax is detailed in the Unit Registry Developer's Guide. The REST Request tab on the query interface gives you a quick look at the syntax of the last query made through the interface. You can open this URL in your web browser to see what the response from the server looks like before it gets formatted into a neat HTML table.

Note that the web service will automatically determine what type of response to send (XML, JSON, or text) based on the 'Accept' header sent by your browser, so different browsers may give different responses. However, these responses differ in formatting only - the content of a response will always be the same for a given request, regardless of format./

There are many possibilities for using the Unit Registry web service. If you're interested in developing with the Unit Registry, you can read the Technical Documents page or get involved with the Unit Working Group.