# Routing Units Routing Units are the spatial units in SWAT+ that allow us to lump outputs and route them to any other spatial object. Routing Units do not have a lot of properties as they mostly serve the purpose of collecting hydrographs. The simulation of the processes generating those hydrographs is controlled by the properties of the individual elements within a routing unit. * [**rout\_unit.rtu**](/io-docs/introduction-1/routing-units/untitled.md) references other files specifying the elements that are part of a Routing Unit and its topographic and field properties. * [**rout\_unit.def**](/io-docs/introduction-1/routing-units/untitled-1.md) specifies which elements a Routing Unit contains. * [**rout\_unit.ele**](/io-docs/introduction-1/routing-units/untitled-2.md) lists all elements that are part of a Routing Unit. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://swatplus.gitbook.io/io-docs/introduction-1/routing-units.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.