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### 2. Ground Distance to Grid

#### a. Ground to Ellipsoid

Figure L-2 Ground to Geodetic |

We computed geodetic distances in Chapter K - those can be converted to meters to use here.

However, we'll do the computations from scratch using Equation H-2 to.

Equation H-2 Jerry's -33.902 meter geoid height will be used as a project average.

##### (1) Geodetic distance *Jerry-A1*

##### (2) Geodetic distance *Jerry-B7*

#### b. Ellipsoid to Grid

Figure L-3 Geodetic to Grid |

We'll use and compare the same reductions for UTM as we did for SPC. Table L-2 shows the grid scale at each point and how they were obtained.

Table L-2 Grid Scales |
||

Point |
Scale |
Source |

A1 |
1.00020 6404 | software |

Jerry-A1 midpoint |
1.00020 9086 | Equation H-4 |

Jerry |
1.00021 177 | datasheet |

Jerry-B7 midpoint |
1.00021 5856 | Equation H-4 |

B7 |
1.00020 8953 | software |

*Jerry*'s CF from the datasheet is 1.00016 082.

Because the process is similar to SPC grid reduction, computations are not shown but results are summarized in Tables L-3 and L-4.

Table L-3LineJerry-A1Grid Reduction ComparisonsD_{E}x kk

Grid Dist, m

Diff, m

Wtd Ave k1.00020 9086 1305.3993

- -

Average k1.00020 9087

1305.3993

0.0000

Jerry's k1.00021 177

1305.4028

+0.0035

Combined FactorD_{H}x CF1.00016 082

1305.4000

+0.0007

Unlike SPC reduction, using

Table L-4LineJerry-B7Grid Reduction ComparisonsD_{E}x kk

Grid Dist, m

Diff, m

Wtd Ave k1.00021 4025

1568.8175

- -

Average k1.00021 0362

1568.8175

0.0000

Jerry's k1.00021 177

1568.8111

-0.0064

Combined FactorD_{H}x CF1.00016 082

1568.8173

-0.0002

Jerry's scale as a project average resulted in the largest differences. Average line scale worked well.Jerry's CF reduction had small (inconsequential?) differences. Using CF reduction could be sufficient if the elevations of pointsA1andB7represent the range across the project.