How do I extract a texture map from a terrain?

I used the Export Terrain script to generate a .obj and opened it in Maya.

I'd also like to get my procedurally generated texture map out (I was using TerrainToolkit) so I can work with it in Maya and Photoshop.

Is there a way to do this?

As far as I know, there is no complete "procedurally created terrain texture" in Unity, because as a single map it would have to be an enormous file. Instead, the terrain texture is a result of the tiled terrain textures you assigned via the inspector and a splat map.

To get the best quality in Maya, I'd suggest you export the splat map and use the HyperShade to recreate the procedural map from Unity. I did a similar thing some time ago, and it worked fine (If you want, I could explain the Maya shader-setup).

You can view your splat map in the project panel: it is a child of your terrain object. Select the splat map in the project panel and convert it via this script into a PNG:

// For saving splat map as PNG file. 
import System.IO; 

@MenuItem("Assets/Export Texture") 
static function Apply () { 
   var texture : Texture2D = Selection.activeObject as Texture2D; 
   if (texture == null) { 
      EditorUtility.DisplayDialog("Select Texture", "You Must Select a Texture first!", "Ok"); 
      return; 
   } 

   var bytes = texture.EncodeToPNG(); 
   File.WriteAllBytes(Application.dataPath + "/exported_texture.png", bytes); 
} 

Source: The script is mentioned in this forum thread.

Alternatively, I'm sure you could find a script to export a scaled down version of the terrain map.. (or the quick and dirty method: just take a screenshot from the top view) ;)