horizontal measurement?

[perfectera]

I am writing a small manual and need a short phrase which describes a measuring operation to determine if a surface is flat or not by using a level. For example, can we say horizontal measurement?
Please give me some alternatives.
Thanks!

[Tdol]

If it is horizontal, it is level. I would use something like to check whether it's level. (Not an engineer, carpenter, etc)

[emsr2d2]

Now use a spirit level to check the surface is level.

[perfectera]

Thanks for your responses.
I actually need a short one to use as the title of the operation instead of a long sentence.
How about check the levelness of something?

[emsr2d2]

Check it is level.

[perfectera]

How about horizontal survey?

[Rover_KE]

Definitely not.

[perfectera]

Why is horizontal survey wrong?

[5jj]

Why is horizontal survey wrong?

Because it simply does not mean checking that something is level. Checking that something is level is not 'measuring' or 'surveying'. You have to use the word 'level' somehow.

'Checking that X is level' may not be very literary, but it's what you are trying to do.

[SoothingDave]

GDT: Parallelism vs. Flatness

There are measurements and specifications for "flatness."