Document ID: chunk:federal_register_of_legislation:F2023L00159:reg:2
Version: federal_register_of_legislation:F2023L00159
Segment Type: reg
Provision Reference: reg 2
Character Range: 24249–25227

2  Average ground height
 (1) The average ground height at the mth increment on the nth radial is calculated as follows:
         Step 1: Determine the associated latitude and longitude of the mth increment on the nth radial (lmn, Lmn) as calculated in item 3 of this Schedule.
         Step 2: Identify the DEM-3S cell represented by (lmn, Lmn).
Note: See subitem (2) below for identifying the DEM-3S cell in a particular case.
         Step 3: Bound the identified DEM-3S cell with the 8 adjacent DEM-3S cells in a 3 x 3 matrix and obtain each DEM-3S cell height attribute (as shown in Diagram 2).
         Step 4: Determine the average value of the 9 DEM-3S cell heights for each cell in the the 3 x 3 matrix.

Diagram 2 Calculating average ground height
 (2) If the seconds component of (lmn, Lmn) has a modulus of zero when divided by 0.0025, then the corresponding DEM-3S cell, for the purposes Step 2 in subitem (1), is the adjacent DEM-3S cell with the minimum height.