Transforms provide control over the texture map placement on object surfaces. Most Projection and Generator nodes offer similar controls, but the Transform nodes provide an additional level of control for texture placement. The values in a Transform node are multiplied by the identical values in a Projection or Generator node. Note that you can also use the Transform nodes to control geometry object placement in a scene.
Transforms are usually paired with a Projection node in order to place a texture map on an object's surface.