I am having a lighting issue with my material. When I shine a light on it in one direction its black, and in the other direction it looks normal.
Its hard to explain so I included screenshots (I am unable to upload pic to the forums so i needed to use imugr. I hope this is ok)
://imgur/a/WNaYg
Any help would be greatly appreciated.
-what happens when you disconnect the normal map?
-replace the landscape coord with a texture coordinate node
-do you get the same effect when you just have one of those meshes in your scene? 
Looks like the issue is in fact with my normal map. Things look fine without it.
I an very new to this, So do you know what I would need to do with the normal map to fix this issue?
Do you use the “normal map” texture compression in the texture settings + in the texture sample node in the material?
What happens when you flip the green channel of your normal map (in the texture settings)
Oh sweet, Did not know there were such options for the textures. changing the compression to “normal map” fixed the issue. Thank you for you assistance, I learned a lot. Applying what I learned here as improved the look of all my textures.
Thanks again