DOC/grdgradient.rst: Update URL link to "Hill-Shading and the Reflect…

…ance Map" by Horn (1981) (#8583)
GenericMappingTools · Sep 22, 2024 · 7809736 · 7809736
1 parent 9242e57
commit 7809736
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/doc/rst/source/grdgradient.rst b/doc/rst/source/grdgradient.rst
@@ -265,7 +265,7 @@ References
 
 Horn, B.K.P., Hill-Shading and the Reflectance Map, Proceedings of the
 IEEE, Vol. 69, No. 1, January 1981, pp. 14-47.
-(http://people.csail.mit.edu/bkph/papers/Hill-Shading.pdf)
+(https://www.researchgate.net/publication/2996084_Hill_shading_and_the_reflectance_map)
 
 See Also
 --------