---
type: "operation"
title: "StructureMap $transform"
resource: "StructureMap"
operation: "transform"
---
# structuremap $transform

Model Instance Transformation

**Description:** The transform operation takes input content, applies a structure map transform, and then returns the output.

**Comments:** The input and return are specified as 'Resources'. In most usage of the $transform operation, either the input or return content is not a valid FHIR resource. In these cases, the return type is actually a [Binary](binary.html) resource. For this operation, the Binary resources may be encoded directly, using a mime-type, as shown in the example. Note: this specification does not yet address the means by which the servers may know the correct mime types for the various content involved

**Affects State:** false

**System:** false

**Type:** true

**Instance:** true

**URL:** http://hl7.org/fhir/build/OperationDefinition/StructureMap-transform


## Parameters

- **source** [in] 0..1 uri — The structure map to apply. This is only needed if the operation is invoked at the resource level and no structureMap has been provided. If the $transform operation is invoked on a particular structure map, this will be ignored by the server
- **sourceMap** [in] 0..1 StructureMap — The structure map to apply. This is only needed when the operation is invoked at the resource level and no URI has been provided.
- **supportingMap** [in] 0..* StructureMap — StructureMap resources that support the source map. If a source URL is provided, the map can be provided in this parameter (or it can be provided as sourceMap).
- **srcMap** [in] 0..* string — The same as structureMap, but the resource is provided in the mapping language rather than as a structureMap.
- **content** [in] 1..1 Resource — The logical content to transform
- **return** [out] 1..1 Resource — The result of the transform