User-manual/Image-orthorectification.md

@@ -229,7 +229,7 @@ There are three methods for positioning reference points:
    - Click on the pixel in the image to locate the Ground Reference Point (GRP); the image coordinates **_I_** and **_J_** will then be populated.
 > :thumbsup: You can zoom in for better visibility of a point. You can also delete or reorder reference points, as well as modify, copy, or paste the coordinates of reference points in the input table.
 
-Repeat this operation for all reference points (at least 4 for 2D orthorectification (ideal: 15-25 points); at least 6 for 3D orthorectification (ideal: 20-35 points); see [principles of orthorectification](#approfondissements) for more details).
+Repeat this operation for all reference points (at least 4 for 2D orthorectification (ideal: 15-25 points); at least 6 for 3D orthorectification (ideal: 20-35 points); see [principles of orthorectification](#mag-the-pinhole-camera-model-and-its-solution-general-3d-case) for more details).
 
 The **_End Entry_** button finalizes the operation and creates a file in the project directory: **_outputs.dir\\GRP.dat_**.