For example, in a cemetery built on a mountain, the sitting direction of the tomb should conform to the mountain situation, and then the sitting direction is not the most important. Sometimes a river flows through the flat land, depending on the direction of the river. All plains also depend on the surrounding roads.
In reality, there are many east-west cemeteries, such as Fushou Garden in Henan. Although they are all flat, the tombs in the cemetery are basically east-west, but they also feel very harmonious.
As long as it does not violate the general principles and conforms to the natural environment, it is a good reason to choose the tomb site.