# Calculate the MEF for a STANAG

The Calculate Max Elevation Figures tool computes the maximum elevation figures for a NATO Standardization Agreement (STANAG) based on the type of the highest vertical obstruction in a quadrangle. Two obstruction types influence the calculation: human-made and natural terrain. The calculation differs if one type is higher than the other.

The table below associates the STANAG term with the corresponding Calculate Max Elevation Figures tool.

STANAG termParameter name

Non represented allowance

MEF Vertical Obstruction Allowance

Obstruction elevation accuracy figure

Vertical Obstruction Accuracy Value

Terrain elevation accuracy figure

Terrain Accuracy Value

When a human-made vertical obstruction is higher than the highest natural terrain feature within a designated quadrangle, the Calculate Max Elevation Figures tool follows this process:

1. Determine the elevation of the top of the highest human-made obstruction.
2. Add the obstruction elevation accuracy figure, which takes inaccuracies in measuring the elevation of an obstruction into account.
3. Determine the terrain accuracy figure and add it to the sum.
4. Round the resultant figure up to the next higher 100-foot level, if necessary, to achieve a complete value in even hundreds of feet.

### Example

```Elevation of highest obstruction (above mean sea level)    =  6300
Obstruction elevation accuracy figure                         + 25
Sum elevation + elevation accuracy figure                  =  6325
Add a terrain height accuracy figure to the sum
(assessed as 50 feet)                                      + 50
Sum of terrain height accuracy figure and sum              =  6375

Raise to next higher 100-foot level                        =  6400
Maximum Elevation Figure (MEF)                             =    64```

## Natural terrain feature vertical obstruction

The Calculate Max Elevation Figures tool computes maximum elevation figures following this process if it is a natural terrain feature:

1. Determine the elevation of the top of the highest natural obstruction.
2. Determine the elevation of the highest natural terrain feature at mean sea level, plus the nonrepresented allowance.
3. Determine the terrain accuracy figure and add it to the sum.
4. Round the resultant figure up to the next higher 100-foot level, if necessary, to achieve a complete value in even hundreds of feet.

### Example

```Highest Terrain Elevation above mean sea level         = 1510
Nonrepresented allowance                                + 200
Sum of highest terrain elevation and NRA               = 1710
Add a terrain height accuracy figure to the sum
(assessed as 50 feet)                                 + 50
Sum of terrain height accuracy figure with
highest terrain elevation and NRA                  = 1760

Raise to the next higher 100-foot level                = 1800
Maximum Elevation Figure (MEF)                         =   18```