## Coordinate Systems Self Study

### Question (2)

A survey in southwestern Missouri was referenced to the state's West SPC zone. The adjusted coordinates and scaled elevations of two surveyed points are shown in the following table.

Point |
North (m) |
East (m) |
Elev (m) |

Bobo |
63,690.932 | 916,159.330 | 445 |

Nancy |
64,097.181 | 915,857.743 | 470 |

Geoid height in the project area is -28.7 meters.

What is the horizontal ground distance between the points?

**Solution**

** **Steps

*(1) Compute grid distance from coordinates*

*(2) Convert grid distance to geodetic*

Use NAD83 Coord Conversion workbook to determine SPC grid scale at both points.

Divide grid distance by average scale to get geodetic distance.

(*3) Convert geodetic distance to ground*

Use average elevation to compute EF.

Divide geodetic distance by EF to get ground.