Not an exact match on Petrie Triangulation Plan but (could) be something to this! If before the 3rd pyramid (G3) was built they could of used line of sight from the SE corners of G1 and G2 to establish the corner point for the wall.

It looks like Petrie (might?) of choose survey points J and H to use for his triangulation mapping with the wall corner in mind. It’s possible Petrie choose survey point H because it was due east of the wall corner and survey point J because it was due south of the east side of G1.




Did you notice this? If you take the square formed by the south side of G1 and the wall corner.




And moved it up to the north side of G1 then the south side of the square meets the center of G3.





In other words the wall corner should be about 440 cubits south of the center of G3.


RLH