Editing Gravity anomaly (section)

===Bouguer plate correction===
{{main|Bouguer anomaly}}
The free-air anomaly does not take into account the layer of material (after terrain leveling) outside the reference ellipsoid. The gravitational attraction of this layer or plate is taken into account by the Bouguer plate correction, which is {{val|−0.0419|e=-3}} ρ ''h'' mgal m<sup>2</sup> kg<sup>−1</sup>. The density of crustal rock, ρ, is usually taken to be 2670&nbsp;kg m<sup>−3</sup> so the Bouguer plate correction is usually taken as −0.1119 mgal m<sup>−1</sup> ''h''. Here ''h'' is the elevation above the reference ellipsoid.{{sfn|Lowrie|2007|p=80}}

The remaining gravity anomaly at this point in the reduction is called the ''Bouguer anomaly''. That is, the Bouguer anomaly is:{{sfn|Lowrie|2007|pp=83–84}}
<math display="block">\Delta g_B = g_m + (\Delta g_{BP} + \Delta g_{FA} + \Delta g_T + \Delta g_\text{tide}) - g_n</math>